-zcache-y := tmem.o
+zcache-y := zcache-main.o tmem.o
obj-$(CONFIG_ZCACHE) += zcache.o
--- /dev/null
+/*
+ * zcache.c
+ *
+ * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
+ * Copyright (c) 2010,2011, Nitin Gupta
+ *
+ * Zcache provides an in-kernel "host implementation" for transcendent memory
+ * and, thus indirectly, for cleancache and frontswap. Zcache includes two
+ * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
+ * 1) "compression buddies" ("zbud") is used for ephemeral pages
+ * 2) xvmalloc is used for persistent pages.
+ * Xvmalloc (based on the TLSF allocator) has very low fragmentation
+ * so maximizes space efficiency, while zbud allows pairs (and potentially,
+ * in the future, more than a pair of) compressed pages to be closely linked
+ * so that reclaiming can be done via the kernel's physical-page-oriented
+ * "shrinker" interface.
+ *
+ * [1] For a definition of page-accessible memory (aka PAM), see:
+ * http://marc.info/?l=linux-mm&m=127811271605009
+ */
+
+#include <linux/cpu.h>
+#include <linux/highmem.h>
+#include <linux/list.h>
+#include <linux/lzo.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include "tmem.h"
+
+#include "../zram/xvmalloc.h" /* if built in drivers/staging */
+
+#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
+#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
+#endif
+#ifdef CONFIG_CLEANCACHE
+#include <linux/cleancache.h>
+#endif
+#ifdef CONFIG_FRONTSWAP
+#include <linux/frontswap.h>
+#endif
+
+#if 0
+/* this is more aggressive but may cause other problems? */
+#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
+#else
+#define ZCACHE_GFP_MASK \
+ (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
+#endif
+
+#define MAX_POOLS_PER_CLIENT 16
+
+#define MAX_CLIENTS 16
+#define LOCAL_CLIENT ((uint16_t)-1)
+struct zcache_client {
+ struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
+ struct xv_pool *xvpool;
+ bool allocated;
+ atomic_t refcount;
+};
+
+static struct zcache_client zcache_host;
+static struct zcache_client zcache_clients[MAX_CLIENTS];
+
+static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
+{
+ BUG_ON(cli == NULL);
+ if (cli == &zcache_host)
+ return LOCAL_CLIENT;
+ return cli - &zcache_clients[0];
+}
+
+static inline bool is_local_client(struct zcache_client *cli)
+{
+ return cli == &zcache_host;
+}
+
+/**********
+ * Compression buddies ("zbud") provides for packing two (or, possibly
+ * in the future, more) compressed ephemeral pages into a single "raw"
+ * (physical) page and tracking them with data structures so that
+ * the raw pages can be easily reclaimed.
+ *
+ * A zbud page ("zbpg") is an aligned page containing a list_head,
+ * a lock, and two "zbud headers". The remainder of the physical
+ * page is divided up into aligned 64-byte "chunks" which contain
+ * the compressed data for zero, one, or two zbuds. Each zbpg
+ * resides on: (1) an "unused list" if it has no zbuds; (2) a
+ * "buddied" list if it is fully populated with two zbuds; or
+ * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
+ * the one unbuddied zbud uses. The data inside a zbpg cannot be
+ * read or written unless the zbpg's lock is held.
+ */
+
+#define ZBH_SENTINEL 0x43214321
+#define ZBPG_SENTINEL 0xdeadbeef
+
+#define ZBUD_MAX_BUDS 2
+
+struct zbud_hdr {
+ uint16_t client_id;
+ uint16_t pool_id;
+ struct tmem_oid oid;
+ uint32_t index;
+ uint16_t size; /* compressed size in bytes, zero means unused */
+ DECL_SENTINEL
+};
+
+struct zbud_page {
+ struct list_head bud_list;
+ spinlock_t lock;
+ struct zbud_hdr buddy[ZBUD_MAX_BUDS];
+ DECL_SENTINEL
+ /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
+};
+
+#define CHUNK_SHIFT 6
+#define CHUNK_SIZE (1 << CHUNK_SHIFT)
+#define CHUNK_MASK (~(CHUNK_SIZE-1))
+#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
+ CHUNK_MASK) >> CHUNK_SHIFT)
+#define MAX_CHUNK (NCHUNKS-1)
+
+static struct {
+ struct list_head list;
+ unsigned count;
+} zbud_unbuddied[NCHUNKS];
+/* list N contains pages with N chunks USED and NCHUNKS-N unused */
+/* element 0 is never used but optimizing that isn't worth it */
+static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
+
+struct list_head zbud_buddied_list;
+static unsigned long zcache_zbud_buddied_count;
+
+/* protects the buddied list and all unbuddied lists */
+static DEFINE_SPINLOCK(zbud_budlists_spinlock);
+
+static LIST_HEAD(zbpg_unused_list);
+static unsigned long zcache_zbpg_unused_list_count;
+
+/* protects the unused page list */
+static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
+
+static atomic_t zcache_zbud_curr_raw_pages;
+static atomic_t zcache_zbud_curr_zpages;
+static unsigned long zcache_zbud_curr_zbytes;
+static unsigned long zcache_zbud_cumul_zpages;
+static unsigned long zcache_zbud_cumul_zbytes;
+static unsigned long zcache_compress_poor;
+static unsigned long zcache_mean_compress_poor;
+
+/* forward references */
+static void *zcache_get_free_page(void);
+static void zcache_free_page(void *p);
+
+/*
+ * zbud helper functions
+ */
+
+static inline unsigned zbud_max_buddy_size(void)
+{
+ return MAX_CHUNK << CHUNK_SHIFT;
+}
+
+static inline unsigned zbud_size_to_chunks(unsigned size)
+{
+ BUG_ON(size == 0 || size > zbud_max_buddy_size());
+ return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
+}
+
+static inline int zbud_budnum(struct zbud_hdr *zh)
+{
+ unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
+ struct zbud_page *zbpg = NULL;
+ unsigned budnum = -1U;
+ int i;
+
+ for (i = 0; i < ZBUD_MAX_BUDS; i++)
+ if (offset == offsetof(typeof(*zbpg), buddy[i])) {
+ budnum = i;
+ break;
+ }
+ BUG_ON(budnum == -1U);
+ return budnum;
+}
+
+static char *zbud_data(struct zbud_hdr *zh, unsigned size)
+{
+ struct zbud_page *zbpg;
+ char *p;
+ unsigned budnum;
+
+ ASSERT_SENTINEL(zh, ZBH);
+ budnum = zbud_budnum(zh);
+ BUG_ON(size == 0 || size > zbud_max_buddy_size());
+ zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
+ ASSERT_SPINLOCK(&zbpg->lock);
+ p = (char *)zbpg;
+ if (budnum == 0)
+ p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
+ CHUNK_MASK);
+ else if (budnum == 1)
+ p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
+ return p;
+}
+
+/*
+ * zbud raw page management
+ */
+
+static struct zbud_page *zbud_alloc_raw_page(void)
+{
+ struct zbud_page *zbpg = NULL;
+ struct zbud_hdr *zh0, *zh1;
+ bool recycled = 0;
+
+ /* if any pages on the zbpg list, use one */
+ spin_lock(&zbpg_unused_list_spinlock);
+ if (!list_empty(&zbpg_unused_list)) {
+ zbpg = list_first_entry(&zbpg_unused_list,
+ struct zbud_page, bud_list);
+ list_del_init(&zbpg->bud_list);
+ zcache_zbpg_unused_list_count--;
+ recycled = 1;
+ }
+ spin_unlock(&zbpg_unused_list_spinlock);
+ if (zbpg == NULL)
+ /* none on zbpg list, try to get a kernel page */
+ zbpg = zcache_get_free_page();
+ if (likely(zbpg != NULL)) {
+ INIT_LIST_HEAD(&zbpg->bud_list);
+ zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
+ spin_lock_init(&zbpg->lock);
+ if (recycled) {
+ ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
+ SET_SENTINEL(zbpg, ZBPG);
+ BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
+ BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
+ } else {
+ atomic_inc(&zcache_zbud_curr_raw_pages);
+ INIT_LIST_HEAD(&zbpg->bud_list);
+ SET_SENTINEL(zbpg, ZBPG);
+ zh0->size = 0; zh1->size = 0;
+ tmem_oid_set_invalid(&zh0->oid);
+ tmem_oid_set_invalid(&zh1->oid);
+ }
+ }
+ return zbpg;
+}
+
+static void zbud_free_raw_page(struct zbud_page *zbpg)
+{
+ struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
+
+ ASSERT_SENTINEL(zbpg, ZBPG);
+ BUG_ON(!list_empty(&zbpg->bud_list));
+ ASSERT_SPINLOCK(&zbpg->lock);
+ BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
+ BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
+ INVERT_SENTINEL(zbpg, ZBPG);
+ spin_unlock(&zbpg->lock);
+ spin_lock(&zbpg_unused_list_spinlock);
+ list_add(&zbpg->bud_list, &zbpg_unused_list);
+ zcache_zbpg_unused_list_count++;
+ spin_unlock(&zbpg_unused_list_spinlock);
+}
+
+/*
+ * core zbud handling routines
+ */
+
+static unsigned zbud_free(struct zbud_hdr *zh)
+{
+ unsigned size;
+
+ ASSERT_SENTINEL(zh, ZBH);
+ BUG_ON(!tmem_oid_valid(&zh->oid));
+ size = zh->size;
+ BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
+ zh->size = 0;
+ tmem_oid_set_invalid(&zh->oid);
+ INVERT_SENTINEL(zh, ZBH);
+ zcache_zbud_curr_zbytes -= size;
+ atomic_dec(&zcache_zbud_curr_zpages);
+ return size;
+}
+
+static void zbud_free_and_delist(struct zbud_hdr *zh)
+{
+ unsigned chunks;
+ struct zbud_hdr *zh_other;
+ unsigned budnum = zbud_budnum(zh), size;
+ struct zbud_page *zbpg =
+ container_of(zh, struct zbud_page, buddy[budnum]);
+
+ spin_lock(&zbpg->lock);
+ if (list_empty(&zbpg->bud_list)) {
+ /* ignore zombie page... see zbud_evict_pages() */
+ spin_unlock(&zbpg->lock);
+ return;
+ }
+ size = zbud_free(zh);
+ ASSERT_SPINLOCK(&zbpg->lock);
+ zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
+ if (zh_other->size == 0) { /* was unbuddied: unlist and free */
+ chunks = zbud_size_to_chunks(size) ;
+ spin_lock(&zbud_budlists_spinlock);
+ BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
+ list_del_init(&zbpg->bud_list);
+ zbud_unbuddied[chunks].count--;
+ spin_unlock(&zbud_budlists_spinlock);
+ zbud_free_raw_page(zbpg);
+ } else { /* was buddied: move remaining buddy to unbuddied list */
+ chunks = zbud_size_to_chunks(zh_other->size) ;
+ spin_lock(&zbud_budlists_spinlock);
+ list_del_init(&zbpg->bud_list);
+ zcache_zbud_buddied_count--;
+ list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
+ zbud_unbuddied[chunks].count++;
+ spin_unlock(&zbud_budlists_spinlock);
+ spin_unlock(&zbpg->lock);
+ }
+}
+
+static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
+ struct tmem_oid *oid,
+ uint32_t index, struct page *page,
+ void *cdata, unsigned size)
+{
+ struct zbud_hdr *zh0, *zh1, *zh = NULL;
+ struct zbud_page *zbpg = NULL, *ztmp;
+ unsigned nchunks;
+ char *to;
+ int i, found_good_buddy = 0;
+
+ nchunks = zbud_size_to_chunks(size) ;
+ for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
+ spin_lock(&zbud_budlists_spinlock);
+ if (!list_empty(&zbud_unbuddied[i].list)) {
+ list_for_each_entry_safe(zbpg, ztmp,
+ &zbud_unbuddied[i].list, bud_list) {
+ if (spin_trylock(&zbpg->lock)) {
+ found_good_buddy = i;
+ goto found_unbuddied;
+ }
+ }
+ }
+ spin_unlock(&zbud_budlists_spinlock);
+ }
+ /* didn't find a good buddy, try allocating a new page */
+ zbpg = zbud_alloc_raw_page();
+ if (unlikely(zbpg == NULL))
+ goto out;
+ /* ok, have a page, now compress the data before taking locks */
+ spin_lock(&zbpg->lock);
+ spin_lock(&zbud_budlists_spinlock);
+ list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
+ zbud_unbuddied[nchunks].count++;
+ zh = &zbpg->buddy[0];
+ goto init_zh;
+
+found_unbuddied:
+ ASSERT_SPINLOCK(&zbpg->lock);
+ zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
+ BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
+ if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
+ ASSERT_SENTINEL(zh0, ZBH);
+ zh = zh1;
+ } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
+ ASSERT_SENTINEL(zh1, ZBH);
+ zh = zh0;
+ } else
+ BUG();
+ list_del_init(&zbpg->bud_list);
+ zbud_unbuddied[found_good_buddy].count--;
+ list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
+ zcache_zbud_buddied_count++;
+
+init_zh:
+ SET_SENTINEL(zh, ZBH);
+ zh->size = size;
+ zh->index = index;
+ zh->oid = *oid;
+ zh->pool_id = pool_id;
+ zh->client_id = client_id;
+ /* can wait to copy the data until the list locks are dropped */
+ spin_unlock(&zbud_budlists_spinlock);
+
+ to = zbud_data(zh, size);
+ memcpy(to, cdata, size);
+ spin_unlock(&zbpg->lock);
+ zbud_cumul_chunk_counts[nchunks]++;
+ atomic_inc(&zcache_zbud_curr_zpages);
+ zcache_zbud_cumul_zpages++;
+ zcache_zbud_curr_zbytes += size;
+ zcache_zbud_cumul_zbytes += size;
+out:
+ return zh;
+}
+
+static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
+{
+ struct zbud_page *zbpg;
+ unsigned budnum = zbud_budnum(zh);
+ size_t out_len = PAGE_SIZE;
+ char *to_va, *from_va;
+ unsigned size;
+ int ret = 0;
+
+ zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
+ spin_lock(&zbpg->lock);
+ if (list_empty(&zbpg->bud_list)) {
+ /* ignore zombie page... see zbud_evict_pages() */
+ ret = -EINVAL;
+ goto out;
+ }
+ ASSERT_SENTINEL(zh, ZBH);
+ BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
+ to_va = kmap_atomic(page, KM_USER0);
+ size = zh->size;
+ from_va = zbud_data(zh, size);
+ ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
+ BUG_ON(ret != LZO_E_OK);
+ BUG_ON(out_len != PAGE_SIZE);
+ kunmap_atomic(to_va, KM_USER0);
+out:
+ spin_unlock(&zbpg->lock);
+ return ret;
+}
+
+/*
+ * The following routines handle shrinking of ephemeral pages by evicting
+ * pages "least valuable" first.
+ */
+
+static unsigned long zcache_evicted_raw_pages;
+static unsigned long zcache_evicted_buddied_pages;
+static unsigned long zcache_evicted_unbuddied_pages;
+
+static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
+ uint16_t poolid);
+static void zcache_put_pool(struct tmem_pool *pool);
+
+/*
+ * Flush and free all zbuds in a zbpg, then free the pageframe
+ */
+static void zbud_evict_zbpg(struct zbud_page *zbpg)
+{
+ struct zbud_hdr *zh;
+ int i, j;
+ uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
+ uint32_t index[ZBUD_MAX_BUDS];
+ struct tmem_oid oid[ZBUD_MAX_BUDS];
+ struct tmem_pool *pool;
+
+ ASSERT_SPINLOCK(&zbpg->lock);
+ BUG_ON(!list_empty(&zbpg->bud_list));
+ for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
+ zh = &zbpg->buddy[i];
+ if (zh->size) {
+ client_id[j] = zh->client_id;
+ pool_id[j] = zh->pool_id;
+ oid[j] = zh->oid;
+ index[j] = zh->index;
+ j++;
+ zbud_free(zh);
+ }
+ }
+ spin_unlock(&zbpg->lock);
+ for (i = 0; i < j; i++) {
+ pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
+ if (pool != NULL) {
+ tmem_flush_page(pool, &oid[i], index[i]);
+ zcache_put_pool(pool);
+ }
+ }
+ ASSERT_SENTINEL(zbpg, ZBPG);
+ spin_lock(&zbpg->lock);
+ zbud_free_raw_page(zbpg);
+}
+
+/*
+ * Free nr pages. This code is funky because we want to hold the locks
+ * protecting various lists for as short a time as possible, and in some
+ * circumstances the list may change asynchronously when the list lock is
+ * not held. In some cases we also trylock not only to avoid waiting on a
+ * page in use by another cpu, but also to avoid potential deadlock due to
+ * lock inversion.
+ */
+static void zbud_evict_pages(int nr)
+{
+ struct zbud_page *zbpg;
+ int i;
+
+ /* first try freeing any pages on unused list */
+retry_unused_list:
+ spin_lock_bh(&zbpg_unused_list_spinlock);
+ if (!list_empty(&zbpg_unused_list)) {
+ /* can't walk list here, since it may change when unlocked */
+ zbpg = list_first_entry(&zbpg_unused_list,
+ struct zbud_page, bud_list);
+ list_del_init(&zbpg->bud_list);
+ zcache_zbpg_unused_list_count--;
+ atomic_dec(&zcache_zbud_curr_raw_pages);
+ spin_unlock_bh(&zbpg_unused_list_spinlock);
+ zcache_free_page(zbpg);
+ zcache_evicted_raw_pages++;
+ if (--nr <= 0)
+ goto out;
+ goto retry_unused_list;
+ }
+ spin_unlock_bh(&zbpg_unused_list_spinlock);
+
+ /* now try freeing unbuddied pages, starting with least space avail */
+ for (i = 0; i < MAX_CHUNK; i++) {
+retry_unbud_list_i:
+ spin_lock_bh(&zbud_budlists_spinlock);
+ if (list_empty(&zbud_unbuddied[i].list)) {
+ spin_unlock_bh(&zbud_budlists_spinlock);
+ continue;
+ }
+ list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
+ if (unlikely(!spin_trylock(&zbpg->lock)))
+ continue;
+ list_del_init(&zbpg->bud_list);
+ zbud_unbuddied[i].count--;
+ spin_unlock(&zbud_budlists_spinlock);
+ zcache_evicted_unbuddied_pages++;
+ /* want budlists unlocked when doing zbpg eviction */
+ zbud_evict_zbpg(zbpg);
+ local_bh_enable();
+ if (--nr <= 0)
+ goto out;
+ goto retry_unbud_list_i;
+ }
+ spin_unlock_bh(&zbud_budlists_spinlock);
+ }
+
+ /* as a last resort, free buddied pages */
+retry_bud_list:
+ spin_lock_bh(&zbud_budlists_spinlock);
+ if (list_empty(&zbud_buddied_list)) {
+ spin_unlock_bh(&zbud_budlists_spinlock);
+ goto out;
+ }
+ list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
+ if (unlikely(!spin_trylock(&zbpg->lock)))
+ continue;
+ list_del_init(&zbpg->bud_list);
+ zcache_zbud_buddied_count--;
+ spin_unlock(&zbud_budlists_spinlock);
+ zcache_evicted_buddied_pages++;
+ /* want budlists unlocked when doing zbpg eviction */
+ zbud_evict_zbpg(zbpg);
+ local_bh_enable();
+ if (--nr <= 0)
+ goto out;
+ goto retry_bud_list;
+ }
+ spin_unlock_bh(&zbud_budlists_spinlock);
+out:
+ return;
+}
+
+static void zbud_init(void)
+{
+ int i;
+
+ INIT_LIST_HEAD(&zbud_buddied_list);
+ zcache_zbud_buddied_count = 0;
+ for (i = 0; i < NCHUNKS; i++) {
+ INIT_LIST_HEAD(&zbud_unbuddied[i].list);
+ zbud_unbuddied[i].count = 0;
+ }
+}
+
+#ifdef CONFIG_SYSFS
+/*
+ * These sysfs routines show a nice distribution of how many zbpg's are
+ * currently (and have ever been placed) in each unbuddied list. It's fun
+ * to watch but can probably go away before final merge.
+ */
+static int zbud_show_unbuddied_list_counts(char *buf)
+{
+ int i;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++)
+ p += sprintf(p, "%u ", zbud_unbuddied[i].count);
+ return p - buf;
+}
+
+static int zbud_show_cumul_chunk_counts(char *buf)
+{
+ unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
+ unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
+ unsigned long total_chunks_lte_42 = 0;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++) {
+ p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
+ chunks += zbud_cumul_chunk_counts[i];
+ total_chunks += zbud_cumul_chunk_counts[i];
+ sum_total_chunks += i * zbud_cumul_chunk_counts[i];
+ if (i == 21)
+ total_chunks_lte_21 = total_chunks;
+ if (i == 32)
+ total_chunks_lte_32 = total_chunks;
+ if (i == 42)
+ total_chunks_lte_42 = total_chunks;
+ }
+ p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
+ total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
+ chunks == 0 ? 0 : sum_total_chunks / chunks);
+ return p - buf;
+}
+#endif
+
+/**********
+ * This "zv" PAM implementation combines the TLSF-based xvMalloc
+ * with lzo1x compression to maximize the amount of data that can
+ * be packed into a physical page.
+ *
+ * Zv represents a PAM page with the index and object (plus a "size" value
+ * necessary for decompression) immediately preceding the compressed data.
+ */
+
+#define ZVH_SENTINEL 0x43214321
+
+struct zv_hdr {
+ uint32_t pool_id;
+ struct tmem_oid oid;
+ uint32_t index;
+ DECL_SENTINEL
+};
+
+/* rudimentary policy limits */
+/* total number of persistent pages may not exceed this percentage */
+static unsigned int zv_page_count_policy_percent = 75;
+/*
+ * byte count defining poor compression; pages with greater zsize will be
+ * rejected
+ */
+static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
+/*
+ * byte count defining poor *mean* compression; pages with greater zsize
+ * will be rejected until sufficient better-compressed pages are accepted
+ * driving the man below this threshold
+ */
+static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
+
+static unsigned long zv_curr_dist_counts[NCHUNKS];
+static unsigned long zv_cumul_dist_counts[NCHUNKS];
+
+static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
+ struct tmem_oid *oid, uint32_t index,
+ void *cdata, unsigned clen)
+{
+ struct page *page;
+ struct zv_hdr *zv = NULL;
+ uint32_t offset;
+ int alloc_size = clen + sizeof(struct zv_hdr);
+ int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
+ int ret;
+
+ BUG_ON(!irqs_disabled());
+ BUG_ON(chunks >= NCHUNKS);
+ ret = xv_malloc(xvpool, alloc_size,
+ &page, &offset, ZCACHE_GFP_MASK);
+ if (unlikely(ret))
+ goto out;
+ zv_curr_dist_counts[chunks]++;
+ zv_cumul_dist_counts[chunks]++;
+ zv = kmap_atomic(page, KM_USER0) + offset;
+ zv->index = index;
+ zv->oid = *oid;
+ zv->pool_id = pool_id;
+ SET_SENTINEL(zv, ZVH);
+ memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
+ kunmap_atomic(zv, KM_USER0);
+out:
+ return zv;
+}
+
+static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
+{
+ unsigned long flags;
+ struct page *page;
+ uint32_t offset;
+ uint16_t size = xv_get_object_size(zv);
+ int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
+
+ ASSERT_SENTINEL(zv, ZVH);
+ BUG_ON(chunks >= NCHUNKS);
+ zv_curr_dist_counts[chunks]--;
+ size -= sizeof(*zv);
+ BUG_ON(size == 0);
+ INVERT_SENTINEL(zv, ZVH);
+ page = virt_to_page(zv);
+ offset = (unsigned long)zv & ~PAGE_MASK;
+ local_irq_save(flags);
+ xv_free(xvpool, page, offset);
+ local_irq_restore(flags);
+}
+
+static void zv_decompress(struct page *page, struct zv_hdr *zv)
+{
+ size_t clen = PAGE_SIZE;
+ char *to_va;
+ unsigned size;
+ int ret;
+
+ ASSERT_SENTINEL(zv, ZVH);
+ size = xv_get_object_size(zv) - sizeof(*zv);
+ BUG_ON(size == 0);
+ to_va = kmap_atomic(page, KM_USER0);
+ ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
+ size, to_va, &clen);
+ kunmap_atomic(to_va, KM_USER0);
+ BUG_ON(ret != LZO_E_OK);
+ BUG_ON(clen != PAGE_SIZE);
+}
+
+#ifdef CONFIG_SYSFS
+/*
+ * show a distribution of compression stats for zv pages.
+ */
+
+static int zv_curr_dist_counts_show(char *buf)
+{
+ unsigned long i, n, chunks = 0, sum_total_chunks = 0;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++) {
+ n = zv_curr_dist_counts[i];
+ p += sprintf(p, "%lu ", n);
+ chunks += n;
+ sum_total_chunks += i * n;
+ }
+ p += sprintf(p, "mean:%lu\n",
+ chunks == 0 ? 0 : sum_total_chunks / chunks);
+ return p - buf;
+}
+
+static int zv_cumul_dist_counts_show(char *buf)
+{
+ unsigned long i, n, chunks = 0, sum_total_chunks = 0;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++) {
+ n = zv_cumul_dist_counts[i];
+ p += sprintf(p, "%lu ", n);
+ chunks += n;
+ sum_total_chunks += i * n;
+ }
+ p += sprintf(p, "mean:%lu\n",
+ chunks == 0 ? 0 : sum_total_chunks / chunks);
+ return p - buf;
+}
+
+/*
+ * setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
+ * pages that don't compress to less than this value (including metadata
+ * overhead) to be rejected. We don't allow the value to get too close
+ * to PAGE_SIZE.
+ */
+static ssize_t zv_max_zsize_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", zv_max_zsize);
+}
+
+static ssize_t zv_max_zsize_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
+ return -EINVAL;
+ zv_max_zsize = val;
+ return count;
+}
+
+/*
+ * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
+ * pages that don't compress to less than this value (including metadata
+ * overhead) to be rejected UNLESS the mean compression is also smaller
+ * than this value. In other words, we are load-balancing-by-zsize the
+ * accepted pages. Again, we don't allow the value to get too close
+ * to PAGE_SIZE.
+ */
+static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", zv_max_mean_zsize);
+}
+
+static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
+ return -EINVAL;
+ zv_max_mean_zsize = val;
+ return count;
+}
+
+/*
+ * setting zv_page_count_policy_percent via sysfs sets an upper bound of
+ * persistent (e.g. swap) pages that will be retained according to:
+ * (zv_page_count_policy_percent * totalram_pages) / 100)
+ * when that limit is reached, further puts will be rejected (until
+ * some pages have been flushed). Note that, due to compression,
+ * this number may exceed 100; it defaults to 75 and we set an
+ * arbitary limit of 150. A poor choice will almost certainly result
+ * in OOM's, so this value should only be changed prudently.
+ */
+static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", zv_page_count_policy_percent);
+}
+
+static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err || (val == 0) || (val > 150))
+ return -EINVAL;
+ zv_page_count_policy_percent = val;
+ return count;
+}
+
+static struct kobj_attribute zcache_zv_max_zsize_attr = {
+ .attr = { .name = "zv_max_zsize", .mode = 0644 },
+ .show = zv_max_zsize_show,
+ .store = zv_max_zsize_store,
+};
+
+static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
+ .attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
+ .show = zv_max_mean_zsize_show,
+ .store = zv_max_mean_zsize_store,
+};
+
+static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
+ .attr = { .name = "zv_page_count_policy_percent",
+ .mode = 0644 },
+ .show = zv_page_count_policy_percent_show,
+ .store = zv_page_count_policy_percent_store,
+};
+#endif
+
+/*
+ * zcache core code starts here
+ */
+
+/* useful stats not collected by cleancache or frontswap */
+static unsigned long zcache_flush_total;
+static unsigned long zcache_flush_found;
+static unsigned long zcache_flobj_total;
+static unsigned long zcache_flobj_found;
+static unsigned long zcache_failed_eph_puts;
+static unsigned long zcache_failed_pers_puts;
+
+/*
+ * Tmem operations assume the poolid implies the invoking client.
+ * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
+ * RAMster has each client numbered by cluster node, and a KVM version
+ * of zcache would have one client per guest and each client might
+ * have a poolid==N.
+ */
+static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
+{
+ struct tmem_pool *pool = NULL;
+ struct zcache_client *cli = NULL;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else {
+ if (cli_id >= MAX_CLIENTS)
+ goto out;
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ }
+ if (poolid < MAX_POOLS_PER_CLIENT) {
+ pool = cli->tmem_pools[poolid];
+ if (pool != NULL)
+ atomic_inc(&pool->refcount);
+ }
+out:
+ return pool;
+}
+
+static void zcache_put_pool(struct tmem_pool *pool)
+{
+ struct zcache_client *cli = NULL;
+
+ if (pool == NULL)
+ BUG();
+ cli = pool->client;
+ atomic_dec(&pool->refcount);
+ atomic_dec(&cli->refcount);
+}
+
+int zcache_new_client(uint16_t cli_id)
+{
+ struct zcache_client *cli = NULL;
+ int ret = -1;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ if (cli->allocated)
+ goto out;
+ cli->allocated = 1;
+#ifdef CONFIG_FRONTSWAP
+ cli->xvpool = xv_create_pool();
+ if (cli->xvpool == NULL)
+ goto out;
+#endif
+ ret = 0;
+out:
+ return ret;
+}
+
+/* counters for debugging */
+static unsigned long zcache_failed_get_free_pages;
+static unsigned long zcache_failed_alloc;
+static unsigned long zcache_put_to_flush;
+static unsigned long zcache_aborted_preload;
+static unsigned long zcache_aborted_shrink;
+
+/*
+ * Ensure that memory allocation requests in zcache don't result
+ * in direct reclaim requests via the shrinker, which would cause
+ * an infinite loop. Maybe a GFP flag would be better?
+ */
+static DEFINE_SPINLOCK(zcache_direct_reclaim_lock);
+
+/*
+ * for now, used named slabs so can easily track usage; later can
+ * either just use kmalloc, or perhaps add a slab-like allocator
+ * to more carefully manage total memory utilization
+ */
+static struct kmem_cache *zcache_objnode_cache;
+static struct kmem_cache *zcache_obj_cache;
+static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_obj_count_max;
+static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_objnode_count_max;
+
+/*
+ * to avoid memory allocation recursion (e.g. due to direct reclaim), we
+ * preload all necessary data structures so the hostops callbacks never
+ * actually do a malloc
+ */
+struct zcache_preload {
+ void *page;
+ struct tmem_obj *obj;
+ int nr;
+ struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
+};
+static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
+
+static int zcache_do_preload(struct tmem_pool *pool)
+{
+ struct zcache_preload *kp;
+ struct tmem_objnode *objnode;
+ struct tmem_obj *obj;
+ void *page;
+ int ret = -ENOMEM;
+
+ if (unlikely(zcache_objnode_cache == NULL))
+ goto out;
+ if (unlikely(zcache_obj_cache == NULL))
+ goto out;
+ if (!spin_trylock(&zcache_direct_reclaim_lock)) {
+ zcache_aborted_preload++;
+ goto out;
+ }
+ preempt_disable();
+ kp = &__get_cpu_var(zcache_preloads);
+ while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
+ preempt_enable_no_resched();
+ objnode = kmem_cache_alloc(zcache_objnode_cache,
+ ZCACHE_GFP_MASK);
+ if (unlikely(objnode == NULL)) {
+ zcache_failed_alloc++;
+ goto unlock_out;
+ }
+ preempt_disable();
+ kp = &__get_cpu_var(zcache_preloads);
+ if (kp->nr < ARRAY_SIZE(kp->objnodes))
+ kp->objnodes[kp->nr++] = objnode;
+ else
+ kmem_cache_free(zcache_objnode_cache, objnode);
+ }
+ preempt_enable_no_resched();
+ obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
+ if (unlikely(obj == NULL)) {
+ zcache_failed_alloc++;
+ goto unlock_out;
+ }
+ page = (void *)__get_free_page(ZCACHE_GFP_MASK);
+ if (unlikely(page == NULL)) {
+ zcache_failed_get_free_pages++;
+ kmem_cache_free(zcache_obj_cache, obj);
+ goto unlock_out;
+ }
+ preempt_disable();
+ kp = &__get_cpu_var(zcache_preloads);
+ if (kp->obj == NULL)
+ kp->obj = obj;
+ else
+ kmem_cache_free(zcache_obj_cache, obj);
+ if (kp->page == NULL)
+ kp->page = page;
+ else
+ free_page((unsigned long)page);
+ ret = 0;
+unlock_out:
+ spin_unlock(&zcache_direct_reclaim_lock);
+out:
+ return ret;
+}
+
+static void *zcache_get_free_page(void)
+{
+ struct zcache_preload *kp;
+ void *page;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ page = kp->page;
+ BUG_ON(page == NULL);
+ kp->page = NULL;
+ return page;
+}
+
+static void zcache_free_page(void *p)
+{
+ free_page((unsigned long)p);
+}
+
+/*
+ * zcache implementation for tmem host ops
+ */
+
+static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
+{
+ struct tmem_objnode *objnode = NULL;
+ unsigned long count;
+ struct zcache_preload *kp;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ if (kp->nr <= 0)
+ goto out;
+ objnode = kp->objnodes[kp->nr - 1];
+ BUG_ON(objnode == NULL);
+ kp->objnodes[kp->nr - 1] = NULL;
+ kp->nr--;
+ count = atomic_inc_return(&zcache_curr_objnode_count);
+ if (count > zcache_curr_objnode_count_max)
+ zcache_curr_objnode_count_max = count;
+out:
+ return objnode;
+}
+
+static void zcache_objnode_free(struct tmem_objnode *objnode,
+ struct tmem_pool *pool)
+{
+ atomic_dec(&zcache_curr_objnode_count);
+ BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
+ kmem_cache_free(zcache_objnode_cache, objnode);
+}
+
+static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
+{
+ struct tmem_obj *obj = NULL;
+ unsigned long count;
+ struct zcache_preload *kp;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ obj = kp->obj;
+ BUG_ON(obj == NULL);
+ kp->obj = NULL;
+ count = atomic_inc_return(&zcache_curr_obj_count);
+ if (count > zcache_curr_obj_count_max)
+ zcache_curr_obj_count_max = count;
+ return obj;
+}
+
+static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
+{
+ atomic_dec(&zcache_curr_obj_count);
+ BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
+ kmem_cache_free(zcache_obj_cache, obj);
+}
+
+static struct tmem_hostops zcache_hostops = {
+ .obj_alloc = zcache_obj_alloc,
+ .obj_free = zcache_obj_free,
+ .objnode_alloc = zcache_objnode_alloc,
+ .objnode_free = zcache_objnode_free,
+};
+
+/*
+ * zcache implementations for PAM page descriptor ops
+ */
+
+static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_eph_pampd_count_max;
+static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_pers_pampd_count_max;
+
+/* forward reference */
+static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
+
+static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
+ struct tmem_pool *pool, struct tmem_oid *oid,
+ uint32_t index)
+{
+ void *pampd = NULL, *cdata;
+ size_t clen;
+ int ret;
+ unsigned long count;
+ struct page *page = virt_to_page(data);
+ struct zcache_client *cli = pool->client;
+ uint16_t client_id = get_client_id_from_client(cli);
+ unsigned long zv_mean_zsize;
+ unsigned long curr_pers_pampd_count;
+
+ if (eph) {
+ ret = zcache_compress(page, &cdata, &clen);
+ if (ret == 0)
+ goto out;
+ if (clen == 0 || clen > zbud_max_buddy_size()) {
+ zcache_compress_poor++;
+ goto out;
+ }
+ pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
+ index, page, cdata, clen);
+ if (pampd != NULL) {
+ count = atomic_inc_return(&zcache_curr_eph_pampd_count);
+ if (count > zcache_curr_eph_pampd_count_max)
+ zcache_curr_eph_pampd_count_max = count;
+ }
+ } else {
+ curr_pers_pampd_count =
+ atomic_read(&zcache_curr_pers_pampd_count);
+ if (curr_pers_pampd_count >
+ (zv_page_count_policy_percent * totalram_pages) / 100)
+ goto out;
+ ret = zcache_compress(page, &cdata, &clen);
+ if (ret == 0)
+ goto out;
+ /* reject if compression is too poor */
+ if (clen > zv_max_zsize) {
+ zcache_compress_poor++;
+ goto out;
+ }
+ /* reject if mean compression is too poor */
+ if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
+ zv_mean_zsize = xv_get_total_size_bytes(cli->xvpool) /
+ curr_pers_pampd_count;
+ if (zv_mean_zsize > zv_max_mean_zsize) {
+ zcache_mean_compress_poor++;
+ goto out;
+ }
+ }
+ pampd = (void *)zv_create(cli->xvpool, pool->pool_id,
+ oid, index, cdata, clen);
+ if (pampd == NULL)
+ goto out;
+ count = atomic_inc_return(&zcache_curr_pers_pampd_count);
+ if (count > zcache_curr_pers_pampd_count_max)
+ zcache_curr_pers_pampd_count_max = count;
+ }
+out:
+ return pampd;
+}
+
+/*
+ * fill the pageframe corresponding to the struct page with the data
+ * from the passed pampd
+ */
+static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
+ void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ int ret = 0;
+
+ BUG_ON(is_ephemeral(pool));
+ zv_decompress(virt_to_page(data), pampd);
+ return ret;
+}
+
+/*
+ * fill the pageframe corresponding to the struct page with the data
+ * from the passed pampd
+ */
+static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
+ void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ int ret = 0;
+
+ BUG_ON(!is_ephemeral(pool));
+ zbud_decompress(virt_to_page(data), pampd);
+ zbud_free_and_delist((struct zbud_hdr *)pampd);
+ atomic_dec(&zcache_curr_eph_pampd_count);
+ return ret;
+}
+
+/*
+ * free the pampd and remove it from any zcache lists
+ * pampd must no longer be pointed to from any tmem data structures!
+ */
+static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ struct zcache_client *cli = pool->client;
+
+ if (is_ephemeral(pool)) {
+ zbud_free_and_delist((struct zbud_hdr *)pampd);
+ atomic_dec(&zcache_curr_eph_pampd_count);
+ BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
+ } else {
+ zv_free(cli->xvpool, (struct zv_hdr *)pampd);
+ atomic_dec(&zcache_curr_pers_pampd_count);
+ BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
+ }
+}
+
+static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
+{
+}
+
+static void zcache_pampd_new_obj(struct tmem_obj *obj)
+{
+}
+
+static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
+{
+ return -1;
+}
+
+static bool zcache_pampd_is_remote(void *pampd)
+{
+ return 0;
+}
+
+static struct tmem_pamops zcache_pamops = {
+ .create = zcache_pampd_create,
+ .get_data = zcache_pampd_get_data,
+ .get_data_and_free = zcache_pampd_get_data_and_free,
+ .free = zcache_pampd_free,
+ .free_obj = zcache_pampd_free_obj,
+ .new_obj = zcache_pampd_new_obj,
+ .replace_in_obj = zcache_pampd_replace_in_obj,
+ .is_remote = zcache_pampd_is_remote,
+};
+
+/*
+ * zcache compression/decompression and related per-cpu stuff
+ */
+
+#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
+#define LZO_DSTMEM_PAGE_ORDER 1
+static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
+static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
+
+static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
+{
+ int ret = 0;
+ unsigned char *dmem = __get_cpu_var(zcache_dstmem);
+ unsigned char *wmem = __get_cpu_var(zcache_workmem);
+ char *from_va;
+
+ BUG_ON(!irqs_disabled());
+ if (unlikely(dmem == NULL || wmem == NULL))
+ goto out; /* no buffer, so can't compress */
+ from_va = kmap_atomic(from, KM_USER0);
+ mb();
+ ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
+ BUG_ON(ret != LZO_E_OK);
+ *out_va = dmem;
+ kunmap_atomic(from_va, KM_USER0);
+ ret = 1;
+out:
+ return ret;
+}
+
+
+static int zcache_cpu_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
+{
+ int cpu = (long)pcpu;
+ struct zcache_preload *kp;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
+ GFP_KERNEL | __GFP_REPEAT,
+ LZO_DSTMEM_PAGE_ORDER),
+ per_cpu(zcache_workmem, cpu) =
+ kzalloc(LZO1X_MEM_COMPRESS,
+ GFP_KERNEL | __GFP_REPEAT);
+ break;
+ case CPU_DEAD:
+ case CPU_UP_CANCELED:
+ free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
+ LZO_DSTMEM_PAGE_ORDER);
+ per_cpu(zcache_dstmem, cpu) = NULL;
+ kfree(per_cpu(zcache_workmem, cpu));
+ per_cpu(zcache_workmem, cpu) = NULL;
+ kp = &per_cpu(zcache_preloads, cpu);
+ while (kp->nr) {
+ kmem_cache_free(zcache_objnode_cache,
+ kp->objnodes[kp->nr - 1]);
+ kp->objnodes[kp->nr - 1] = NULL;
+ kp->nr--;
+ }
+ kmem_cache_free(zcache_obj_cache, kp->obj);
+ free_page((unsigned long)kp->page);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block zcache_cpu_notifier_block = {
+ .notifier_call = zcache_cpu_notifier
+};
+
+#ifdef CONFIG_SYSFS
+#define ZCACHE_SYSFS_RO(_name) \
+ static ssize_t zcache_##_name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+ { \
+ return sprintf(buf, "%lu\n", zcache_##_name); \
+ } \
+ static struct kobj_attribute zcache_##_name##_attr = { \
+ .attr = { .name = __stringify(_name), .mode = 0444 }, \
+ .show = zcache_##_name##_show, \
+ }
+
+#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
+ static ssize_t zcache_##_name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+ { \
+ return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
+ } \
+ static struct kobj_attribute zcache_##_name##_attr = { \
+ .attr = { .name = __stringify(_name), .mode = 0444 }, \
+ .show = zcache_##_name##_show, \
+ }
+
+#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
+ static ssize_t zcache_##_name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+ { \
+ return _func(buf); \
+ } \
+ static struct kobj_attribute zcache_##_name##_attr = { \
+ .attr = { .name = __stringify(_name), .mode = 0444 }, \
+ .show = zcache_##_name##_show, \
+ }
+
+ZCACHE_SYSFS_RO(curr_obj_count_max);
+ZCACHE_SYSFS_RO(curr_objnode_count_max);
+ZCACHE_SYSFS_RO(flush_total);
+ZCACHE_SYSFS_RO(flush_found);
+ZCACHE_SYSFS_RO(flobj_total);
+ZCACHE_SYSFS_RO(flobj_found);
+ZCACHE_SYSFS_RO(failed_eph_puts);
+ZCACHE_SYSFS_RO(failed_pers_puts);
+ZCACHE_SYSFS_RO(zbud_curr_zbytes);
+ZCACHE_SYSFS_RO(zbud_cumul_zpages);
+ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
+ZCACHE_SYSFS_RO(zbud_buddied_count);
+ZCACHE_SYSFS_RO(zbpg_unused_list_count);
+ZCACHE_SYSFS_RO(evicted_raw_pages);
+ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
+ZCACHE_SYSFS_RO(evicted_buddied_pages);
+ZCACHE_SYSFS_RO(failed_get_free_pages);
+ZCACHE_SYSFS_RO(failed_alloc);
+ZCACHE_SYSFS_RO(put_to_flush);
+ZCACHE_SYSFS_RO(aborted_preload);
+ZCACHE_SYSFS_RO(aborted_shrink);
+ZCACHE_SYSFS_RO(compress_poor);
+ZCACHE_SYSFS_RO(mean_compress_poor);
+ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
+ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
+ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
+ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
+ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
+ zbud_show_unbuddied_list_counts);
+ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
+ zbud_show_cumul_chunk_counts);
+ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
+ zv_curr_dist_counts_show);
+ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
+ zv_cumul_dist_counts_show);
+
+static struct attribute *zcache_attrs[] = {
+ &zcache_curr_obj_count_attr.attr,
+ &zcache_curr_obj_count_max_attr.attr,
+ &zcache_curr_objnode_count_attr.attr,
+ &zcache_curr_objnode_count_max_attr.attr,
+ &zcache_flush_total_attr.attr,
+ &zcache_flobj_total_attr.attr,
+ &zcache_flush_found_attr.attr,
+ &zcache_flobj_found_attr.attr,
+ &zcache_failed_eph_puts_attr.attr,
+ &zcache_failed_pers_puts_attr.attr,
+ &zcache_compress_poor_attr.attr,
+ &zcache_mean_compress_poor_attr.attr,
+ &zcache_zbud_curr_raw_pages_attr.attr,
+ &zcache_zbud_curr_zpages_attr.attr,
+ &zcache_zbud_curr_zbytes_attr.attr,
+ &zcache_zbud_cumul_zpages_attr.attr,
+ &zcache_zbud_cumul_zbytes_attr.attr,
+ &zcache_zbud_buddied_count_attr.attr,
+ &zcache_zbpg_unused_list_count_attr.attr,
+ &zcache_evicted_raw_pages_attr.attr,
+ &zcache_evicted_unbuddied_pages_attr.attr,
+ &zcache_evicted_buddied_pages_attr.attr,
+ &zcache_failed_get_free_pages_attr.attr,
+ &zcache_failed_alloc_attr.attr,
+ &zcache_put_to_flush_attr.attr,
+ &zcache_aborted_preload_attr.attr,
+ &zcache_aborted_shrink_attr.attr,
+ &zcache_zbud_unbuddied_list_counts_attr.attr,
+ &zcache_zbud_cumul_chunk_counts_attr.attr,
+ &zcache_zv_curr_dist_counts_attr.attr,
+ &zcache_zv_cumul_dist_counts_attr.attr,
+ &zcache_zv_max_zsize_attr.attr,
+ &zcache_zv_max_mean_zsize_attr.attr,
+ &zcache_zv_page_count_policy_percent_attr.attr,
+ NULL,
+};
+
+static struct attribute_group zcache_attr_group = {
+ .attrs = zcache_attrs,
+ .name = "zcache",
+};
+
+#endif /* CONFIG_SYSFS */
+/*
+ * When zcache is disabled ("frozen"), pools can be created and destroyed,
+ * but all puts (and thus all other operations that require memory allocation)
+ * must fail. If zcache is unfrozen, accepts puts, then frozen again,
+ * data consistency requires all puts while frozen to be converted into
+ * flushes.
+ */
+static bool zcache_freeze;
+
+/*
+ * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
+ */
+static int shrink_zcache_memory(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ int ret = -1;
+ int nr = sc->nr_to_scan;
+ gfp_t gfp_mask = sc->gfp_mask;
+
+ if (nr >= 0) {
+ if (!(gfp_mask & __GFP_FS))
+ /* does this case really need to be skipped? */
+ goto out;
+ if (spin_trylock(&zcache_direct_reclaim_lock)) {
+ zbud_evict_pages(nr);
+ spin_unlock(&zcache_direct_reclaim_lock);
+ } else
+ zcache_aborted_shrink++;
+ }
+ ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
+out:
+ return ret;
+}
+
+static struct shrinker zcache_shrinker = {
+ .shrink = shrink_zcache_memory,
+ .seeks = DEFAULT_SEEKS,
+};
+
+/*
+ * zcache shims between cleancache/frontswap ops and tmem
+ */
+
+static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
+ uint32_t index, struct page *page)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+
+ BUG_ON(!irqs_disabled());
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (unlikely(pool == NULL))
+ goto out;
+ if (!zcache_freeze && zcache_do_preload(pool) == 0) {
+ /* preload does preempt_disable on success */
+ ret = tmem_put(pool, oidp, index, page_address(page),
+ PAGE_SIZE, 0, is_ephemeral(pool));
+ if (ret < 0) {
+ if (is_ephemeral(pool))
+ zcache_failed_eph_puts++;
+ else
+ zcache_failed_pers_puts++;
+ }
+ zcache_put_pool(pool);
+ preempt_enable_no_resched();
+ } else {
+ zcache_put_to_flush++;
+ if (atomic_read(&pool->obj_count) > 0)
+ /* the put fails whether the flush succeeds or not */
+ (void)tmem_flush_page(pool, oidp, index);
+ zcache_put_pool(pool);
+ }
+out:
+ return ret;
+}
+
+static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
+ uint32_t index, struct page *page)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+ size_t size = PAGE_SIZE;
+
+ local_irq_save(flags);
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_get(pool, oidp, index, page_address(page),
+ &size, 0, is_ephemeral(pool));
+ zcache_put_pool(pool);
+ }
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_flush_page(int cli_id, int pool_id,
+ struct tmem_oid *oidp, uint32_t index)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ zcache_flush_total++;
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_flush_page(pool, oidp, index);
+ zcache_put_pool(pool);
+ }
+ if (ret >= 0)
+ zcache_flush_found++;
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_flush_object(int cli_id, int pool_id,
+ struct tmem_oid *oidp)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ zcache_flobj_total++;
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_flush_object(pool, oidp);
+ zcache_put_pool(pool);
+ }
+ if (ret >= 0)
+ zcache_flobj_found++;
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_destroy_pool(int cli_id, int pool_id)
+{
+ struct tmem_pool *pool = NULL;
+ struct zcache_client *cli = NULL;
+ int ret = -1;
+
+ if (pool_id < 0)
+ goto out;
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ pool = cli->tmem_pools[pool_id];
+ if (pool == NULL)
+ goto out;
+ cli->tmem_pools[pool_id] = NULL;
+ /* wait for pool activity on other cpus to quiesce */
+ while (atomic_read(&pool->refcount) != 0)
+ ;
+ atomic_dec(&cli->refcount);
+ local_bh_disable();
+ ret = tmem_destroy_pool(pool);
+ local_bh_enable();
+ kfree(pool);
+ pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
+ pool_id, cli_id);
+out:
+ return ret;
+}
+
+static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
+{
+ int poolid = -1;
+ struct tmem_pool *pool;
+ struct zcache_client *cli = NULL;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
+ if (pool == NULL) {
+ pr_info("zcache: pool creation failed: out of memory\n");
+ goto out;
+ }
+
+ for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
+ if (cli->tmem_pools[poolid] == NULL)
+ break;
+ if (poolid >= MAX_POOLS_PER_CLIENT) {
+ pr_info("zcache: pool creation failed: max exceeded\n");
+ kfree(pool);
+ poolid = -1;
+ goto out;
+ }
+ atomic_set(&pool->refcount, 0);
+ pool->client = cli;
+ pool->pool_id = poolid;
+ tmem_new_pool(pool, flags);
+ cli->tmem_pools[poolid] = pool;
+ pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
+ flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
+ poolid, cli_id);
+out:
+ if (cli != NULL)
+ atomic_dec(&cli->refcount);
+ return poolid;
+}
+
+/**********
+ * Two kernel functionalities currently can be layered on top of tmem.
+ * These are "cleancache" which is used as a second-chance cache for clean
+ * page cache pages; and "frontswap" which is used for swap pages
+ * to avoid writes to disk. A generic "shim" is provided here for each
+ * to translate in-kernel semantics to zcache semantics.
+ */
+
+#ifdef CONFIG_CLEANCACHE
+static void zcache_cleancache_put_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index, struct page *page)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ if (likely(ind == index))
+ (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
+}
+
+static int zcache_cleancache_get_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index, struct page *page)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+ int ret = -1;
+
+ if (likely(ind == index))
+ ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
+ return ret;
+}
+
+static void zcache_cleancache_flush_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ if (likely(ind == index))
+ (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
+}
+
+static void zcache_cleancache_flush_inode(int pool_id,
+ struct cleancache_filekey key)
+{
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
+}
+
+static void zcache_cleancache_flush_fs(int pool_id)
+{
+ if (pool_id >= 0)
+ (void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
+}
+
+static int zcache_cleancache_init_fs(size_t pagesize)
+{
+ BUG_ON(sizeof(struct cleancache_filekey) !=
+ sizeof(struct tmem_oid));
+ BUG_ON(pagesize != PAGE_SIZE);
+ return zcache_new_pool(LOCAL_CLIENT, 0);
+}
+
+static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
+{
+ /* shared pools are unsupported and map to private */
+ BUG_ON(sizeof(struct cleancache_filekey) !=
+ sizeof(struct tmem_oid));
+ BUG_ON(pagesize != PAGE_SIZE);
+ return zcache_new_pool(LOCAL_CLIENT, 0);
+}
+
+static struct cleancache_ops zcache_cleancache_ops = {
+ .put_page = zcache_cleancache_put_page,
+ .get_page = zcache_cleancache_get_page,
+ .flush_page = zcache_cleancache_flush_page,
+ .flush_inode = zcache_cleancache_flush_inode,
+ .flush_fs = zcache_cleancache_flush_fs,
+ .init_shared_fs = zcache_cleancache_init_shared_fs,
+ .init_fs = zcache_cleancache_init_fs
+};
+
+struct cleancache_ops zcache_cleancache_register_ops(void)
+{
+ struct cleancache_ops old_ops =
+ cleancache_register_ops(&zcache_cleancache_ops);
+
+ return old_ops;
+}
+#endif
+
+#ifdef CONFIG_FRONTSWAP
+/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+static int zcache_frontswap_poolid = -1;
+
+/*
+ * Swizzling increases objects per swaptype, increasing tmem concurrency
+ * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
+ */
+#define SWIZ_BITS 4
+#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
+#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
+#define iswiz(_ind) (_ind >> SWIZ_BITS)
+
+static inline struct tmem_oid oswiz(unsigned type, u32 ind)
+{
+ struct tmem_oid oid = { .oid = { 0 } };
+ oid.oid[0] = _oswiz(type, ind);
+ return oid;
+}
+
+static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+ int ret = -1;
+ unsigned long flags;
+
+ BUG_ON(!PageLocked(page));
+ if (likely(ind64 == ind)) {
+ local_irq_save(flags);
+ ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind), page);
+ local_irq_restore(flags);
+ }
+ return ret;
+}
+
+/* returns 0 if the page was successfully gotten from frontswap, -1 if
+ * was not present (should never happen!) */
+static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+ int ret = -1;
+
+ BUG_ON(!PageLocked(page));
+ if (likely(ind64 == ind))
+ ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind), page);
+ return ret;
+}
+
+/* flush a single page from frontswap */
+static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+
+ if (likely(ind64 == ind))
+ (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind));
+}
+
+/* flush all pages from the passed swaptype */
+static void zcache_frontswap_flush_area(unsigned type)
+{
+ struct tmem_oid oid;
+ int ind;
+
+ for (ind = SWIZ_MASK; ind >= 0; ind--) {
+ oid = oswiz(type, ind);
+ (void)zcache_flush_object(LOCAL_CLIENT,
+ zcache_frontswap_poolid, &oid);
+ }
+}
+
+static void zcache_frontswap_init(unsigned ignored)
+{
+ /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+ if (zcache_frontswap_poolid < 0)
+ zcache_frontswap_poolid =
+ zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
+}
+
+static struct frontswap_ops zcache_frontswap_ops = {
+ .put_page = zcache_frontswap_put_page,
+ .get_page = zcache_frontswap_get_page,
+ .flush_page = zcache_frontswap_flush_page,
+ .flush_area = zcache_frontswap_flush_area,
+ .init = zcache_frontswap_init
+};
+
+struct frontswap_ops zcache_frontswap_register_ops(void)
+{
+ struct frontswap_ops old_ops =
+ frontswap_register_ops(&zcache_frontswap_ops);
+
+ return old_ops;
+}
+#endif
+
+/*
+ * zcache initialization
+ * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
+ * NOTHING HAPPENS!
+ */
+
+static int zcache_enabled;
+
+static int __init enable_zcache(char *s)
+{
+ zcache_enabled = 1;
+ return 1;
+}
+__setup("zcache", enable_zcache);
+
+/* allow independent dynamic disabling of cleancache and frontswap */
+
+static int use_cleancache = 1;
+
+static int __init no_cleancache(char *s)
+{
+ use_cleancache = 0;
+ return 1;
+}
+
+__setup("nocleancache", no_cleancache);
+
+static int use_frontswap = 1;
+
+static int __init no_frontswap(char *s)
+{
+ use_frontswap = 0;
+ return 1;
+}
+
+__setup("nofrontswap", no_frontswap);
+
+static int __init zcache_init(void)
+{
+#ifdef CONFIG_SYSFS
+ int ret = 0;
+
+ ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
+ if (ret) {
+ pr_err("zcache: can't create sysfs\n");
+ goto out;
+ }
+#endif /* CONFIG_SYSFS */
+#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
+ if (zcache_enabled) {
+ unsigned int cpu;
+
+ tmem_register_hostops(&zcache_hostops);
+ tmem_register_pamops(&zcache_pamops);
+ ret = register_cpu_notifier(&zcache_cpu_notifier_block);
+ if (ret) {
+ pr_err("zcache: can't register cpu notifier\n");
+ goto out;
+ }
+ for_each_online_cpu(cpu) {
+ void *pcpu = (void *)(long)cpu;
+ zcache_cpu_notifier(&zcache_cpu_notifier_block,
+ CPU_UP_PREPARE, pcpu);
+ }
+ }
+ zcache_objnode_cache = kmem_cache_create("zcache_objnode",
+ sizeof(struct tmem_objnode), 0, 0, NULL);
+ zcache_obj_cache = kmem_cache_create("zcache_obj",
+ sizeof(struct tmem_obj), 0, 0, NULL);
+ ret = zcache_new_client(LOCAL_CLIENT);
+ if (ret) {
+ pr_err("zcache: can't create client\n");
+ goto out;
+ }
+#endif
+#ifdef CONFIG_CLEANCACHE
+ if (zcache_enabled && use_cleancache) {
+ struct cleancache_ops old_ops;
+
+ zbud_init();
+ register_shrinker(&zcache_shrinker);
+ old_ops = zcache_cleancache_register_ops();
+ pr_info("zcache: cleancache enabled using kernel "
+ "transcendent memory and compression buddies\n");
+ if (old_ops.init_fs != NULL)
+ pr_warning("zcache: cleancache_ops overridden");
+ }
+#endif
+#ifdef CONFIG_FRONTSWAP
+ if (zcache_enabled && use_frontswap) {
+ struct frontswap_ops old_ops;
+
+ old_ops = zcache_frontswap_register_ops();
+ pr_info("zcache: frontswap enabled using kernel "
+ "transcendent memory and xvmalloc\n");
+ if (old_ops.init != NULL)
+ pr_warning("ktmem: frontswap_ops overridden");
+ }
+#endif
+out:
+ return ret;
+}
+
+module_init(zcache_init)
+++ /dev/null
-/*
- * zcache.c
- *
- * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
- * Copyright (c) 2010,2011, Nitin Gupta
- *
- * Zcache provides an in-kernel "host implementation" for transcendent memory
- * and, thus indirectly, for cleancache and frontswap. Zcache includes two
- * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
- * 1) "compression buddies" ("zbud") is used for ephemeral pages
- * 2) xvmalloc is used for persistent pages.
- * Xvmalloc (based on the TLSF allocator) has very low fragmentation
- * so maximizes space efficiency, while zbud allows pairs (and potentially,
- * in the future, more than a pair of) compressed pages to be closely linked
- * so that reclaiming can be done via the kernel's physical-page-oriented
- * "shrinker" interface.
- *
- * [1] For a definition of page-accessible memory (aka PAM), see:
- * http://marc.info/?l=linux-mm&m=127811271605009
- */
-
-#include <linux/cpu.h>
-#include <linux/highmem.h>
-#include <linux/list.h>
-#include <linux/lzo.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/types.h>
-#include <linux/atomic.h>
-#include "tmem.h"
-
-#include "../zram/xvmalloc.h" /* if built in drivers/staging */
-
-#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
-#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
-#endif
-#ifdef CONFIG_CLEANCACHE
-#include <linux/cleancache.h>
-#endif
-#ifdef CONFIG_FRONTSWAP
-#include <linux/frontswap.h>
-#endif
-
-#if 0
-/* this is more aggressive but may cause other problems? */
-#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
-#else
-#define ZCACHE_GFP_MASK \
- (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
-#endif
-
-#define MAX_POOLS_PER_CLIENT 16
-
-#define MAX_CLIENTS 16
-#define LOCAL_CLIENT ((uint16_t)-1)
-struct zcache_client {
- struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
- struct xv_pool *xvpool;
- bool allocated;
- atomic_t refcount;
-};
-
-static struct zcache_client zcache_host;
-static struct zcache_client zcache_clients[MAX_CLIENTS];
-
-static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
-{
- BUG_ON(cli == NULL);
- if (cli == &zcache_host)
- return LOCAL_CLIENT;
- return cli - &zcache_clients[0];
-}
-
-static inline bool is_local_client(struct zcache_client *cli)
-{
- return cli == &zcache_host;
-}
-
-/**********
- * Compression buddies ("zbud") provides for packing two (or, possibly
- * in the future, more) compressed ephemeral pages into a single "raw"
- * (physical) page and tracking them with data structures so that
- * the raw pages can be easily reclaimed.
- *
- * A zbud page ("zbpg") is an aligned page containing a list_head,
- * a lock, and two "zbud headers". The remainder of the physical
- * page is divided up into aligned 64-byte "chunks" which contain
- * the compressed data for zero, one, or two zbuds. Each zbpg
- * resides on: (1) an "unused list" if it has no zbuds; (2) a
- * "buddied" list if it is fully populated with two zbuds; or
- * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
- * the one unbuddied zbud uses. The data inside a zbpg cannot be
- * read or written unless the zbpg's lock is held.
- */
-
-#define ZBH_SENTINEL 0x43214321
-#define ZBPG_SENTINEL 0xdeadbeef
-
-#define ZBUD_MAX_BUDS 2
-
-struct zbud_hdr {
- uint16_t client_id;
- uint16_t pool_id;
- struct tmem_oid oid;
- uint32_t index;
- uint16_t size; /* compressed size in bytes, zero means unused */
- DECL_SENTINEL
-};
-
-struct zbud_page {
- struct list_head bud_list;
- spinlock_t lock;
- struct zbud_hdr buddy[ZBUD_MAX_BUDS];
- DECL_SENTINEL
- /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
-};
-
-#define CHUNK_SHIFT 6
-#define CHUNK_SIZE (1 << CHUNK_SHIFT)
-#define CHUNK_MASK (~(CHUNK_SIZE-1))
-#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
- CHUNK_MASK) >> CHUNK_SHIFT)
-#define MAX_CHUNK (NCHUNKS-1)
-
-static struct {
- struct list_head list;
- unsigned count;
-} zbud_unbuddied[NCHUNKS];
-/* list N contains pages with N chunks USED and NCHUNKS-N unused */
-/* element 0 is never used but optimizing that isn't worth it */
-static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
-
-struct list_head zbud_buddied_list;
-static unsigned long zcache_zbud_buddied_count;
-
-/* protects the buddied list and all unbuddied lists */
-static DEFINE_SPINLOCK(zbud_budlists_spinlock);
-
-static LIST_HEAD(zbpg_unused_list);
-static unsigned long zcache_zbpg_unused_list_count;
-
-/* protects the unused page list */
-static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
-
-static atomic_t zcache_zbud_curr_raw_pages;
-static atomic_t zcache_zbud_curr_zpages;
-static unsigned long zcache_zbud_curr_zbytes;
-static unsigned long zcache_zbud_cumul_zpages;
-static unsigned long zcache_zbud_cumul_zbytes;
-static unsigned long zcache_compress_poor;
-static unsigned long zcache_mean_compress_poor;
-
-/* forward references */
-static void *zcache_get_free_page(void);
-static void zcache_free_page(void *p);
-
-/*
- * zbud helper functions
- */
-
-static inline unsigned zbud_max_buddy_size(void)
-{
- return MAX_CHUNK << CHUNK_SHIFT;
-}
-
-static inline unsigned zbud_size_to_chunks(unsigned size)
-{
- BUG_ON(size == 0 || size > zbud_max_buddy_size());
- return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
-}
-
-static inline int zbud_budnum(struct zbud_hdr *zh)
-{
- unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
- struct zbud_page *zbpg = NULL;
- unsigned budnum = -1U;
- int i;
-
- for (i = 0; i < ZBUD_MAX_BUDS; i++)
- if (offset == offsetof(typeof(*zbpg), buddy[i])) {
- budnum = i;
- break;
- }
- BUG_ON(budnum == -1U);
- return budnum;
-}
-
-static char *zbud_data(struct zbud_hdr *zh, unsigned size)
-{
- struct zbud_page *zbpg;
- char *p;
- unsigned budnum;
-
- ASSERT_SENTINEL(zh, ZBH);
- budnum = zbud_budnum(zh);
- BUG_ON(size == 0 || size > zbud_max_buddy_size());
- zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
- ASSERT_SPINLOCK(&zbpg->lock);
- p = (char *)zbpg;
- if (budnum == 0)
- p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
- CHUNK_MASK);
- else if (budnum == 1)
- p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
- return p;
-}
-
-/*
- * zbud raw page management
- */
-
-static struct zbud_page *zbud_alloc_raw_page(void)
-{
- struct zbud_page *zbpg = NULL;
- struct zbud_hdr *zh0, *zh1;
- bool recycled = 0;
-
- /* if any pages on the zbpg list, use one */
- spin_lock(&zbpg_unused_list_spinlock);
- if (!list_empty(&zbpg_unused_list)) {
- zbpg = list_first_entry(&zbpg_unused_list,
- struct zbud_page, bud_list);
- list_del_init(&zbpg->bud_list);
- zcache_zbpg_unused_list_count--;
- recycled = 1;
- }
- spin_unlock(&zbpg_unused_list_spinlock);
- if (zbpg == NULL)
- /* none on zbpg list, try to get a kernel page */
- zbpg = zcache_get_free_page();
- if (likely(zbpg != NULL)) {
- INIT_LIST_HEAD(&zbpg->bud_list);
- zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
- spin_lock_init(&zbpg->lock);
- if (recycled) {
- ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
- SET_SENTINEL(zbpg, ZBPG);
- BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
- BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
- } else {
- atomic_inc(&zcache_zbud_curr_raw_pages);
- INIT_LIST_HEAD(&zbpg->bud_list);
- SET_SENTINEL(zbpg, ZBPG);
- zh0->size = 0; zh1->size = 0;
- tmem_oid_set_invalid(&zh0->oid);
- tmem_oid_set_invalid(&zh1->oid);
- }
- }
- return zbpg;
-}
-
-static void zbud_free_raw_page(struct zbud_page *zbpg)
-{
- struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
-
- ASSERT_SENTINEL(zbpg, ZBPG);
- BUG_ON(!list_empty(&zbpg->bud_list));
- ASSERT_SPINLOCK(&zbpg->lock);
- BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
- BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
- INVERT_SENTINEL(zbpg, ZBPG);
- spin_unlock(&zbpg->lock);
- spin_lock(&zbpg_unused_list_spinlock);
- list_add(&zbpg->bud_list, &zbpg_unused_list);
- zcache_zbpg_unused_list_count++;
- spin_unlock(&zbpg_unused_list_spinlock);
-}
-
-/*
- * core zbud handling routines
- */
-
-static unsigned zbud_free(struct zbud_hdr *zh)
-{
- unsigned size;
-
- ASSERT_SENTINEL(zh, ZBH);
- BUG_ON(!tmem_oid_valid(&zh->oid));
- size = zh->size;
- BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
- zh->size = 0;
- tmem_oid_set_invalid(&zh->oid);
- INVERT_SENTINEL(zh, ZBH);
- zcache_zbud_curr_zbytes -= size;
- atomic_dec(&zcache_zbud_curr_zpages);
- return size;
-}
-
-static void zbud_free_and_delist(struct zbud_hdr *zh)
-{
- unsigned chunks;
- struct zbud_hdr *zh_other;
- unsigned budnum = zbud_budnum(zh), size;
- struct zbud_page *zbpg =
- container_of(zh, struct zbud_page, buddy[budnum]);
-
- spin_lock(&zbpg->lock);
- if (list_empty(&zbpg->bud_list)) {
- /* ignore zombie page... see zbud_evict_pages() */
- spin_unlock(&zbpg->lock);
- return;
- }
- size = zbud_free(zh);
- ASSERT_SPINLOCK(&zbpg->lock);
- zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
- if (zh_other->size == 0) { /* was unbuddied: unlist and free */
- chunks = zbud_size_to_chunks(size) ;
- spin_lock(&zbud_budlists_spinlock);
- BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
- list_del_init(&zbpg->bud_list);
- zbud_unbuddied[chunks].count--;
- spin_unlock(&zbud_budlists_spinlock);
- zbud_free_raw_page(zbpg);
- } else { /* was buddied: move remaining buddy to unbuddied list */
- chunks = zbud_size_to_chunks(zh_other->size) ;
- spin_lock(&zbud_budlists_spinlock);
- list_del_init(&zbpg->bud_list);
- zcache_zbud_buddied_count--;
- list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
- zbud_unbuddied[chunks].count++;
- spin_unlock(&zbud_budlists_spinlock);
- spin_unlock(&zbpg->lock);
- }
-}
-
-static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
- struct tmem_oid *oid,
- uint32_t index, struct page *page,
- void *cdata, unsigned size)
-{
- struct zbud_hdr *zh0, *zh1, *zh = NULL;
- struct zbud_page *zbpg = NULL, *ztmp;
- unsigned nchunks;
- char *to;
- int i, found_good_buddy = 0;
-
- nchunks = zbud_size_to_chunks(size) ;
- for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
- spin_lock(&zbud_budlists_spinlock);
- if (!list_empty(&zbud_unbuddied[i].list)) {
- list_for_each_entry_safe(zbpg, ztmp,
- &zbud_unbuddied[i].list, bud_list) {
- if (spin_trylock(&zbpg->lock)) {
- found_good_buddy = i;
- goto found_unbuddied;
- }
- }
- }
- spin_unlock(&zbud_budlists_spinlock);
- }
- /* didn't find a good buddy, try allocating a new page */
- zbpg = zbud_alloc_raw_page();
- if (unlikely(zbpg == NULL))
- goto out;
- /* ok, have a page, now compress the data before taking locks */
- spin_lock(&zbpg->lock);
- spin_lock(&zbud_budlists_spinlock);
- list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
- zbud_unbuddied[nchunks].count++;
- zh = &zbpg->buddy[0];
- goto init_zh;
-
-found_unbuddied:
- ASSERT_SPINLOCK(&zbpg->lock);
- zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
- BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
- if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
- ASSERT_SENTINEL(zh0, ZBH);
- zh = zh1;
- } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
- ASSERT_SENTINEL(zh1, ZBH);
- zh = zh0;
- } else
- BUG();
- list_del_init(&zbpg->bud_list);
- zbud_unbuddied[found_good_buddy].count--;
- list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
- zcache_zbud_buddied_count++;
-
-init_zh:
- SET_SENTINEL(zh, ZBH);
- zh->size = size;
- zh->index = index;
- zh->oid = *oid;
- zh->pool_id = pool_id;
- zh->client_id = client_id;
- /* can wait to copy the data until the list locks are dropped */
- spin_unlock(&zbud_budlists_spinlock);
-
- to = zbud_data(zh, size);
- memcpy(to, cdata, size);
- spin_unlock(&zbpg->lock);
- zbud_cumul_chunk_counts[nchunks]++;
- atomic_inc(&zcache_zbud_curr_zpages);
- zcache_zbud_cumul_zpages++;
- zcache_zbud_curr_zbytes += size;
- zcache_zbud_cumul_zbytes += size;
-out:
- return zh;
-}
-
-static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
-{
- struct zbud_page *zbpg;
- unsigned budnum = zbud_budnum(zh);
- size_t out_len = PAGE_SIZE;
- char *to_va, *from_va;
- unsigned size;
- int ret = 0;
-
- zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
- spin_lock(&zbpg->lock);
- if (list_empty(&zbpg->bud_list)) {
- /* ignore zombie page... see zbud_evict_pages() */
- ret = -EINVAL;
- goto out;
- }
- ASSERT_SENTINEL(zh, ZBH);
- BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
- to_va = kmap_atomic(page, KM_USER0);
- size = zh->size;
- from_va = zbud_data(zh, size);
- ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
- BUG_ON(ret != LZO_E_OK);
- BUG_ON(out_len != PAGE_SIZE);
- kunmap_atomic(to_va, KM_USER0);
-out:
- spin_unlock(&zbpg->lock);
- return ret;
-}
-
-/*
- * The following routines handle shrinking of ephemeral pages by evicting
- * pages "least valuable" first.
- */
-
-static unsigned long zcache_evicted_raw_pages;
-static unsigned long zcache_evicted_buddied_pages;
-static unsigned long zcache_evicted_unbuddied_pages;
-
-static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
- uint16_t poolid);
-static void zcache_put_pool(struct tmem_pool *pool);
-
-/*
- * Flush and free all zbuds in a zbpg, then free the pageframe
- */
-static void zbud_evict_zbpg(struct zbud_page *zbpg)
-{
- struct zbud_hdr *zh;
- int i, j;
- uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
- uint32_t index[ZBUD_MAX_BUDS];
- struct tmem_oid oid[ZBUD_MAX_BUDS];
- struct tmem_pool *pool;
-
- ASSERT_SPINLOCK(&zbpg->lock);
- BUG_ON(!list_empty(&zbpg->bud_list));
- for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
- zh = &zbpg->buddy[i];
- if (zh->size) {
- client_id[j] = zh->client_id;
- pool_id[j] = zh->pool_id;
- oid[j] = zh->oid;
- index[j] = zh->index;
- j++;
- zbud_free(zh);
- }
- }
- spin_unlock(&zbpg->lock);
- for (i = 0; i < j; i++) {
- pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
- if (pool != NULL) {
- tmem_flush_page(pool, &oid[i], index[i]);
- zcache_put_pool(pool);
- }
- }
- ASSERT_SENTINEL(zbpg, ZBPG);
- spin_lock(&zbpg->lock);
- zbud_free_raw_page(zbpg);
-}
-
-/*
- * Free nr pages. This code is funky because we want to hold the locks
- * protecting various lists for as short a time as possible, and in some
- * circumstances the list may change asynchronously when the list lock is
- * not held. In some cases we also trylock not only to avoid waiting on a
- * page in use by another cpu, but also to avoid potential deadlock due to
- * lock inversion.
- */
-static void zbud_evict_pages(int nr)
-{
- struct zbud_page *zbpg;
- int i;
-
- /* first try freeing any pages on unused list */
-retry_unused_list:
- spin_lock_bh(&zbpg_unused_list_spinlock);
- if (!list_empty(&zbpg_unused_list)) {
- /* can't walk list here, since it may change when unlocked */
- zbpg = list_first_entry(&zbpg_unused_list,
- struct zbud_page, bud_list);
- list_del_init(&zbpg->bud_list);
- zcache_zbpg_unused_list_count--;
- atomic_dec(&zcache_zbud_curr_raw_pages);
- spin_unlock_bh(&zbpg_unused_list_spinlock);
- zcache_free_page(zbpg);
- zcache_evicted_raw_pages++;
- if (--nr <= 0)
- goto out;
- goto retry_unused_list;
- }
- spin_unlock_bh(&zbpg_unused_list_spinlock);
-
- /* now try freeing unbuddied pages, starting with least space avail */
- for (i = 0; i < MAX_CHUNK; i++) {
-retry_unbud_list_i:
- spin_lock_bh(&zbud_budlists_spinlock);
- if (list_empty(&zbud_unbuddied[i].list)) {
- spin_unlock_bh(&zbud_budlists_spinlock);
- continue;
- }
- list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
- if (unlikely(!spin_trylock(&zbpg->lock)))
- continue;
- list_del_init(&zbpg->bud_list);
- zbud_unbuddied[i].count--;
- spin_unlock(&zbud_budlists_spinlock);
- zcache_evicted_unbuddied_pages++;
- /* want budlists unlocked when doing zbpg eviction */
- zbud_evict_zbpg(zbpg);
- local_bh_enable();
- if (--nr <= 0)
- goto out;
- goto retry_unbud_list_i;
- }
- spin_unlock_bh(&zbud_budlists_spinlock);
- }
-
- /* as a last resort, free buddied pages */
-retry_bud_list:
- spin_lock_bh(&zbud_budlists_spinlock);
- if (list_empty(&zbud_buddied_list)) {
- spin_unlock_bh(&zbud_budlists_spinlock);
- goto out;
- }
- list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
- if (unlikely(!spin_trylock(&zbpg->lock)))
- continue;
- list_del_init(&zbpg->bud_list);
- zcache_zbud_buddied_count--;
- spin_unlock(&zbud_budlists_spinlock);
- zcache_evicted_buddied_pages++;
- /* want budlists unlocked when doing zbpg eviction */
- zbud_evict_zbpg(zbpg);
- local_bh_enable();
- if (--nr <= 0)
- goto out;
- goto retry_bud_list;
- }
- spin_unlock_bh(&zbud_budlists_spinlock);
-out:
- return;
-}
-
-static void zbud_init(void)
-{
- int i;
-
- INIT_LIST_HEAD(&zbud_buddied_list);
- zcache_zbud_buddied_count = 0;
- for (i = 0; i < NCHUNKS; i++) {
- INIT_LIST_HEAD(&zbud_unbuddied[i].list);
- zbud_unbuddied[i].count = 0;
- }
-}
-
-#ifdef CONFIG_SYSFS
-/*
- * These sysfs routines show a nice distribution of how many zbpg's are
- * currently (and have ever been placed) in each unbuddied list. It's fun
- * to watch but can probably go away before final merge.
- */
-static int zbud_show_unbuddied_list_counts(char *buf)
-{
- int i;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++)
- p += sprintf(p, "%u ", zbud_unbuddied[i].count);
- return p - buf;
-}
-
-static int zbud_show_cumul_chunk_counts(char *buf)
-{
- unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
- unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
- unsigned long total_chunks_lte_42 = 0;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++) {
- p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
- chunks += zbud_cumul_chunk_counts[i];
- total_chunks += zbud_cumul_chunk_counts[i];
- sum_total_chunks += i * zbud_cumul_chunk_counts[i];
- if (i == 21)
- total_chunks_lte_21 = total_chunks;
- if (i == 32)
- total_chunks_lte_32 = total_chunks;
- if (i == 42)
- total_chunks_lte_42 = total_chunks;
- }
- p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
- total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
- chunks == 0 ? 0 : sum_total_chunks / chunks);
- return p - buf;
-}
-#endif
-
-/**********
- * This "zv" PAM implementation combines the TLSF-based xvMalloc
- * with lzo1x compression to maximize the amount of data that can
- * be packed into a physical page.
- *
- * Zv represents a PAM page with the index and object (plus a "size" value
- * necessary for decompression) immediately preceding the compressed data.
- */
-
-#define ZVH_SENTINEL 0x43214321
-
-struct zv_hdr {
- uint32_t pool_id;
- struct tmem_oid oid;
- uint32_t index;
- DECL_SENTINEL
-};
-
-/* rudimentary policy limits */
-/* total number of persistent pages may not exceed this percentage */
-static unsigned int zv_page_count_policy_percent = 75;
-/*
- * byte count defining poor compression; pages with greater zsize will be
- * rejected
- */
-static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
-/*
- * byte count defining poor *mean* compression; pages with greater zsize
- * will be rejected until sufficient better-compressed pages are accepted
- * driving the man below this threshold
- */
-static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
-
-static unsigned long zv_curr_dist_counts[NCHUNKS];
-static unsigned long zv_cumul_dist_counts[NCHUNKS];
-
-static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
- struct tmem_oid *oid, uint32_t index,
- void *cdata, unsigned clen)
-{
- struct page *page;
- struct zv_hdr *zv = NULL;
- uint32_t offset;
- int alloc_size = clen + sizeof(struct zv_hdr);
- int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
- int ret;
-
- BUG_ON(!irqs_disabled());
- BUG_ON(chunks >= NCHUNKS);
- ret = xv_malloc(xvpool, alloc_size,
- &page, &offset, ZCACHE_GFP_MASK);
- if (unlikely(ret))
- goto out;
- zv_curr_dist_counts[chunks]++;
- zv_cumul_dist_counts[chunks]++;
- zv = kmap_atomic(page, KM_USER0) + offset;
- zv->index = index;
- zv->oid = *oid;
- zv->pool_id = pool_id;
- SET_SENTINEL(zv, ZVH);
- memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
- kunmap_atomic(zv, KM_USER0);
-out:
- return zv;
-}
-
-static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
-{
- unsigned long flags;
- struct page *page;
- uint32_t offset;
- uint16_t size = xv_get_object_size(zv);
- int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
-
- ASSERT_SENTINEL(zv, ZVH);
- BUG_ON(chunks >= NCHUNKS);
- zv_curr_dist_counts[chunks]--;
- size -= sizeof(*zv);
- BUG_ON(size == 0);
- INVERT_SENTINEL(zv, ZVH);
- page = virt_to_page(zv);
- offset = (unsigned long)zv & ~PAGE_MASK;
- local_irq_save(flags);
- xv_free(xvpool, page, offset);
- local_irq_restore(flags);
-}
-
-static void zv_decompress(struct page *page, struct zv_hdr *zv)
-{
- size_t clen = PAGE_SIZE;
- char *to_va;
- unsigned size;
- int ret;
-
- ASSERT_SENTINEL(zv, ZVH);
- size = xv_get_object_size(zv) - sizeof(*zv);
- BUG_ON(size == 0);
- to_va = kmap_atomic(page, KM_USER0);
- ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
- size, to_va, &clen);
- kunmap_atomic(to_va, KM_USER0);
- BUG_ON(ret != LZO_E_OK);
- BUG_ON(clen != PAGE_SIZE);
-}
-
-#ifdef CONFIG_SYSFS
-/*
- * show a distribution of compression stats for zv pages.
- */
-
-static int zv_curr_dist_counts_show(char *buf)
-{
- unsigned long i, n, chunks = 0, sum_total_chunks = 0;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++) {
- n = zv_curr_dist_counts[i];
- p += sprintf(p, "%lu ", n);
- chunks += n;
- sum_total_chunks += i * n;
- }
- p += sprintf(p, "mean:%lu\n",
- chunks == 0 ? 0 : sum_total_chunks / chunks);
- return p - buf;
-}
-
-static int zv_cumul_dist_counts_show(char *buf)
-{
- unsigned long i, n, chunks = 0, sum_total_chunks = 0;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++) {
- n = zv_cumul_dist_counts[i];
- p += sprintf(p, "%lu ", n);
- chunks += n;
- sum_total_chunks += i * n;
- }
- p += sprintf(p, "mean:%lu\n",
- chunks == 0 ? 0 : sum_total_chunks / chunks);
- return p - buf;
-}
-
-/*
- * setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
- * pages that don't compress to less than this value (including metadata
- * overhead) to be rejected. We don't allow the value to get too close
- * to PAGE_SIZE.
- */
-static ssize_t zv_max_zsize_show(struct kobject *kobj,
- struct kobj_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%u\n", zv_max_zsize);
-}
-
-static ssize_t zv_max_zsize_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = strict_strtoul(buf, 10, &val);
- if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
- return -EINVAL;
- zv_max_zsize = val;
- return count;
-}
-
-/*
- * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
- * pages that don't compress to less than this value (including metadata
- * overhead) to be rejected UNLESS the mean compression is also smaller
- * than this value. In other words, we are load-balancing-by-zsize the
- * accepted pages. Again, we don't allow the value to get too close
- * to PAGE_SIZE.
- */
-static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
- struct kobj_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%u\n", zv_max_mean_zsize);
-}
-
-static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = strict_strtoul(buf, 10, &val);
- if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
- return -EINVAL;
- zv_max_mean_zsize = val;
- return count;
-}
-
-/*
- * setting zv_page_count_policy_percent via sysfs sets an upper bound of
- * persistent (e.g. swap) pages that will be retained according to:
- * (zv_page_count_policy_percent * totalram_pages) / 100)
- * when that limit is reached, further puts will be rejected (until
- * some pages have been flushed). Note that, due to compression,
- * this number may exceed 100; it defaults to 75 and we set an
- * arbitary limit of 150. A poor choice will almost certainly result
- * in OOM's, so this value should only be changed prudently.
- */
-static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
- struct kobj_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%u\n", zv_page_count_policy_percent);
-}
-
-static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = strict_strtoul(buf, 10, &val);
- if (err || (val == 0) || (val > 150))
- return -EINVAL;
- zv_page_count_policy_percent = val;
- return count;
-}
-
-static struct kobj_attribute zcache_zv_max_zsize_attr = {
- .attr = { .name = "zv_max_zsize", .mode = 0644 },
- .show = zv_max_zsize_show,
- .store = zv_max_zsize_store,
-};
-
-static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
- .attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
- .show = zv_max_mean_zsize_show,
- .store = zv_max_mean_zsize_store,
-};
-
-static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
- .attr = { .name = "zv_page_count_policy_percent",
- .mode = 0644 },
- .show = zv_page_count_policy_percent_show,
- .store = zv_page_count_policy_percent_store,
-};
-#endif
-
-/*
- * zcache core code starts here
- */
-
-/* useful stats not collected by cleancache or frontswap */
-static unsigned long zcache_flush_total;
-static unsigned long zcache_flush_found;
-static unsigned long zcache_flobj_total;
-static unsigned long zcache_flobj_found;
-static unsigned long zcache_failed_eph_puts;
-static unsigned long zcache_failed_pers_puts;
-
-/*
- * Tmem operations assume the poolid implies the invoking client.
- * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
- * RAMster has each client numbered by cluster node, and a KVM version
- * of zcache would have one client per guest and each client might
- * have a poolid==N.
- */
-static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
-{
- struct tmem_pool *pool = NULL;
- struct zcache_client *cli = NULL;
-
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else {
- if (cli_id >= MAX_CLIENTS)
- goto out;
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- atomic_inc(&cli->refcount);
- }
- if (poolid < MAX_POOLS_PER_CLIENT) {
- pool = cli->tmem_pools[poolid];
- if (pool != NULL)
- atomic_inc(&pool->refcount);
- }
-out:
- return pool;
-}
-
-static void zcache_put_pool(struct tmem_pool *pool)
-{
- struct zcache_client *cli = NULL;
-
- if (pool == NULL)
- BUG();
- cli = pool->client;
- atomic_dec(&pool->refcount);
- atomic_dec(&cli->refcount);
-}
-
-int zcache_new_client(uint16_t cli_id)
-{
- struct zcache_client *cli = NULL;
- int ret = -1;
-
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else if ((unsigned int)cli_id < MAX_CLIENTS)
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- if (cli->allocated)
- goto out;
- cli->allocated = 1;
-#ifdef CONFIG_FRONTSWAP
- cli->xvpool = xv_create_pool();
- if (cli->xvpool == NULL)
- goto out;
-#endif
- ret = 0;
-out:
- return ret;
-}
-
-/* counters for debugging */
-static unsigned long zcache_failed_get_free_pages;
-static unsigned long zcache_failed_alloc;
-static unsigned long zcache_put_to_flush;
-static unsigned long zcache_aborted_preload;
-static unsigned long zcache_aborted_shrink;
-
-/*
- * Ensure that memory allocation requests in zcache don't result
- * in direct reclaim requests via the shrinker, which would cause
- * an infinite loop. Maybe a GFP flag would be better?
- */
-static DEFINE_SPINLOCK(zcache_direct_reclaim_lock);
-
-/*
- * for now, used named slabs so can easily track usage; later can
- * either just use kmalloc, or perhaps add a slab-like allocator
- * to more carefully manage total memory utilization
- */
-static struct kmem_cache *zcache_objnode_cache;
-static struct kmem_cache *zcache_obj_cache;
-static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_obj_count_max;
-static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_objnode_count_max;
-
-/*
- * to avoid memory allocation recursion (e.g. due to direct reclaim), we
- * preload all necessary data structures so the hostops callbacks never
- * actually do a malloc
- */
-struct zcache_preload {
- void *page;
- struct tmem_obj *obj;
- int nr;
- struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
-};
-static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
-
-static int zcache_do_preload(struct tmem_pool *pool)
-{
- struct zcache_preload *kp;
- struct tmem_objnode *objnode;
- struct tmem_obj *obj;
- void *page;
- int ret = -ENOMEM;
-
- if (unlikely(zcache_objnode_cache == NULL))
- goto out;
- if (unlikely(zcache_obj_cache == NULL))
- goto out;
- if (!spin_trylock(&zcache_direct_reclaim_lock)) {
- zcache_aborted_preload++;
- goto out;
- }
- preempt_disable();
- kp = &__get_cpu_var(zcache_preloads);
- while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
- preempt_enable_no_resched();
- objnode = kmem_cache_alloc(zcache_objnode_cache,
- ZCACHE_GFP_MASK);
- if (unlikely(objnode == NULL)) {
- zcache_failed_alloc++;
- goto unlock_out;
- }
- preempt_disable();
- kp = &__get_cpu_var(zcache_preloads);
- if (kp->nr < ARRAY_SIZE(kp->objnodes))
- kp->objnodes[kp->nr++] = objnode;
- else
- kmem_cache_free(zcache_objnode_cache, objnode);
- }
- preempt_enable_no_resched();
- obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
- if (unlikely(obj == NULL)) {
- zcache_failed_alloc++;
- goto unlock_out;
- }
- page = (void *)__get_free_page(ZCACHE_GFP_MASK);
- if (unlikely(page == NULL)) {
- zcache_failed_get_free_pages++;
- kmem_cache_free(zcache_obj_cache, obj);
- goto unlock_out;
- }
- preempt_disable();
- kp = &__get_cpu_var(zcache_preloads);
- if (kp->obj == NULL)
- kp->obj = obj;
- else
- kmem_cache_free(zcache_obj_cache, obj);
- if (kp->page == NULL)
- kp->page = page;
- else
- free_page((unsigned long)page);
- ret = 0;
-unlock_out:
- spin_unlock(&zcache_direct_reclaim_lock);
-out:
- return ret;
-}
-
-static void *zcache_get_free_page(void)
-{
- struct zcache_preload *kp;
- void *page;
-
- kp = &__get_cpu_var(zcache_preloads);
- page = kp->page;
- BUG_ON(page == NULL);
- kp->page = NULL;
- return page;
-}
-
-static void zcache_free_page(void *p)
-{
- free_page((unsigned long)p);
-}
-
-/*
- * zcache implementation for tmem host ops
- */
-
-static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
-{
- struct tmem_objnode *objnode = NULL;
- unsigned long count;
- struct zcache_preload *kp;
-
- kp = &__get_cpu_var(zcache_preloads);
- if (kp->nr <= 0)
- goto out;
- objnode = kp->objnodes[kp->nr - 1];
- BUG_ON(objnode == NULL);
- kp->objnodes[kp->nr - 1] = NULL;
- kp->nr--;
- count = atomic_inc_return(&zcache_curr_objnode_count);
- if (count > zcache_curr_objnode_count_max)
- zcache_curr_objnode_count_max = count;
-out:
- return objnode;
-}
-
-static void zcache_objnode_free(struct tmem_objnode *objnode,
- struct tmem_pool *pool)
-{
- atomic_dec(&zcache_curr_objnode_count);
- BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
- kmem_cache_free(zcache_objnode_cache, objnode);
-}
-
-static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
-{
- struct tmem_obj *obj = NULL;
- unsigned long count;
- struct zcache_preload *kp;
-
- kp = &__get_cpu_var(zcache_preloads);
- obj = kp->obj;
- BUG_ON(obj == NULL);
- kp->obj = NULL;
- count = atomic_inc_return(&zcache_curr_obj_count);
- if (count > zcache_curr_obj_count_max)
- zcache_curr_obj_count_max = count;
- return obj;
-}
-
-static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
-{
- atomic_dec(&zcache_curr_obj_count);
- BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
- kmem_cache_free(zcache_obj_cache, obj);
-}
-
-static struct tmem_hostops zcache_hostops = {
- .obj_alloc = zcache_obj_alloc,
- .obj_free = zcache_obj_free,
- .objnode_alloc = zcache_objnode_alloc,
- .objnode_free = zcache_objnode_free,
-};
-
-/*
- * zcache implementations for PAM page descriptor ops
- */
-
-static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_eph_pampd_count_max;
-static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_pers_pampd_count_max;
-
-/* forward reference */
-static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
-
-static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
- struct tmem_pool *pool, struct tmem_oid *oid,
- uint32_t index)
-{
- void *pampd = NULL, *cdata;
- size_t clen;
- int ret;
- unsigned long count;
- struct page *page = virt_to_page(data);
- struct zcache_client *cli = pool->client;
- uint16_t client_id = get_client_id_from_client(cli);
- unsigned long zv_mean_zsize;
- unsigned long curr_pers_pampd_count;
-
- if (eph) {
- ret = zcache_compress(page, &cdata, &clen);
- if (ret == 0)
- goto out;
- if (clen == 0 || clen > zbud_max_buddy_size()) {
- zcache_compress_poor++;
- goto out;
- }
- pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
- index, page, cdata, clen);
- if (pampd != NULL) {
- count = atomic_inc_return(&zcache_curr_eph_pampd_count);
- if (count > zcache_curr_eph_pampd_count_max)
- zcache_curr_eph_pampd_count_max = count;
- }
- } else {
- curr_pers_pampd_count =
- atomic_read(&zcache_curr_pers_pampd_count);
- if (curr_pers_pampd_count >
- (zv_page_count_policy_percent * totalram_pages) / 100)
- goto out;
- ret = zcache_compress(page, &cdata, &clen);
- if (ret == 0)
- goto out;
- /* reject if compression is too poor */
- if (clen > zv_max_zsize) {
- zcache_compress_poor++;
- goto out;
- }
- /* reject if mean compression is too poor */
- if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
- zv_mean_zsize = xv_get_total_size_bytes(cli->xvpool) /
- curr_pers_pampd_count;
- if (zv_mean_zsize > zv_max_mean_zsize) {
- zcache_mean_compress_poor++;
- goto out;
- }
- }
- pampd = (void *)zv_create(cli->xvpool, pool->pool_id,
- oid, index, cdata, clen);
- if (pampd == NULL)
- goto out;
- count = atomic_inc_return(&zcache_curr_pers_pampd_count);
- if (count > zcache_curr_pers_pampd_count_max)
- zcache_curr_pers_pampd_count_max = count;
- }
-out:
- return pampd;
-}
-
-/*
- * fill the pageframe corresponding to the struct page with the data
- * from the passed pampd
- */
-static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
- void *pampd, struct tmem_pool *pool,
- struct tmem_oid *oid, uint32_t index)
-{
- int ret = 0;
-
- BUG_ON(is_ephemeral(pool));
- zv_decompress(virt_to_page(data), pampd);
- return ret;
-}
-
-/*
- * fill the pageframe corresponding to the struct page with the data
- * from the passed pampd
- */
-static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
- void *pampd, struct tmem_pool *pool,
- struct tmem_oid *oid, uint32_t index)
-{
- int ret = 0;
-
- BUG_ON(!is_ephemeral(pool));
- zbud_decompress(virt_to_page(data), pampd);
- zbud_free_and_delist((struct zbud_hdr *)pampd);
- atomic_dec(&zcache_curr_eph_pampd_count);
- return ret;
-}
-
-/*
- * free the pampd and remove it from any zcache lists
- * pampd must no longer be pointed to from any tmem data structures!
- */
-static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
- struct tmem_oid *oid, uint32_t index)
-{
- struct zcache_client *cli = pool->client;
-
- if (is_ephemeral(pool)) {
- zbud_free_and_delist((struct zbud_hdr *)pampd);
- atomic_dec(&zcache_curr_eph_pampd_count);
- BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
- } else {
- zv_free(cli->xvpool, (struct zv_hdr *)pampd);
- atomic_dec(&zcache_curr_pers_pampd_count);
- BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
- }
-}
-
-static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
-{
-}
-
-static void zcache_pampd_new_obj(struct tmem_obj *obj)
-{
-}
-
-static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
-{
- return -1;
-}
-
-static bool zcache_pampd_is_remote(void *pampd)
-{
- return 0;
-}
-
-static struct tmem_pamops zcache_pamops = {
- .create = zcache_pampd_create,
- .get_data = zcache_pampd_get_data,
- .get_data_and_free = zcache_pampd_get_data_and_free,
- .free = zcache_pampd_free,
- .free_obj = zcache_pampd_free_obj,
- .new_obj = zcache_pampd_new_obj,
- .replace_in_obj = zcache_pampd_replace_in_obj,
- .is_remote = zcache_pampd_is_remote,
-};
-
-/*
- * zcache compression/decompression and related per-cpu stuff
- */
-
-#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
-#define LZO_DSTMEM_PAGE_ORDER 1
-static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
-static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
-
-static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
-{
- int ret = 0;
- unsigned char *dmem = __get_cpu_var(zcache_dstmem);
- unsigned char *wmem = __get_cpu_var(zcache_workmem);
- char *from_va;
-
- BUG_ON(!irqs_disabled());
- if (unlikely(dmem == NULL || wmem == NULL))
- goto out; /* no buffer, so can't compress */
- from_va = kmap_atomic(from, KM_USER0);
- mb();
- ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
- BUG_ON(ret != LZO_E_OK);
- *out_va = dmem;
- kunmap_atomic(from_va, KM_USER0);
- ret = 1;
-out:
- return ret;
-}
-
-
-static int zcache_cpu_notifier(struct notifier_block *nb,
- unsigned long action, void *pcpu)
-{
- int cpu = (long)pcpu;
- struct zcache_preload *kp;
-
- switch (action) {
- case CPU_UP_PREPARE:
- per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
- GFP_KERNEL | __GFP_REPEAT,
- LZO_DSTMEM_PAGE_ORDER),
- per_cpu(zcache_workmem, cpu) =
- kzalloc(LZO1X_MEM_COMPRESS,
- GFP_KERNEL | __GFP_REPEAT);
- break;
- case CPU_DEAD:
- case CPU_UP_CANCELED:
- free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
- LZO_DSTMEM_PAGE_ORDER);
- per_cpu(zcache_dstmem, cpu) = NULL;
- kfree(per_cpu(zcache_workmem, cpu));
- per_cpu(zcache_workmem, cpu) = NULL;
- kp = &per_cpu(zcache_preloads, cpu);
- while (kp->nr) {
- kmem_cache_free(zcache_objnode_cache,
- kp->objnodes[kp->nr - 1]);
- kp->objnodes[kp->nr - 1] = NULL;
- kp->nr--;
- }
- kmem_cache_free(zcache_obj_cache, kp->obj);
- free_page((unsigned long)kp->page);
- break;
- default:
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block zcache_cpu_notifier_block = {
- .notifier_call = zcache_cpu_notifier
-};
-
-#ifdef CONFIG_SYSFS
-#define ZCACHE_SYSFS_RO(_name) \
- static ssize_t zcache_##_name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
- { \
- return sprintf(buf, "%lu\n", zcache_##_name); \
- } \
- static struct kobj_attribute zcache_##_name##_attr = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = zcache_##_name##_show, \
- }
-
-#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
- static ssize_t zcache_##_name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
- { \
- return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
- } \
- static struct kobj_attribute zcache_##_name##_attr = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = zcache_##_name##_show, \
- }
-
-#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
- static ssize_t zcache_##_name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
- { \
- return _func(buf); \
- } \
- static struct kobj_attribute zcache_##_name##_attr = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = zcache_##_name##_show, \
- }
-
-ZCACHE_SYSFS_RO(curr_obj_count_max);
-ZCACHE_SYSFS_RO(curr_objnode_count_max);
-ZCACHE_SYSFS_RO(flush_total);
-ZCACHE_SYSFS_RO(flush_found);
-ZCACHE_SYSFS_RO(flobj_total);
-ZCACHE_SYSFS_RO(flobj_found);
-ZCACHE_SYSFS_RO(failed_eph_puts);
-ZCACHE_SYSFS_RO(failed_pers_puts);
-ZCACHE_SYSFS_RO(zbud_curr_zbytes);
-ZCACHE_SYSFS_RO(zbud_cumul_zpages);
-ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
-ZCACHE_SYSFS_RO(zbud_buddied_count);
-ZCACHE_SYSFS_RO(zbpg_unused_list_count);
-ZCACHE_SYSFS_RO(evicted_raw_pages);
-ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
-ZCACHE_SYSFS_RO(evicted_buddied_pages);
-ZCACHE_SYSFS_RO(failed_get_free_pages);
-ZCACHE_SYSFS_RO(failed_alloc);
-ZCACHE_SYSFS_RO(put_to_flush);
-ZCACHE_SYSFS_RO(aborted_preload);
-ZCACHE_SYSFS_RO(aborted_shrink);
-ZCACHE_SYSFS_RO(compress_poor);
-ZCACHE_SYSFS_RO(mean_compress_poor);
-ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
-ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
-ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
-ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
-ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
- zbud_show_unbuddied_list_counts);
-ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
- zbud_show_cumul_chunk_counts);
-ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
- zv_curr_dist_counts_show);
-ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
- zv_cumul_dist_counts_show);
-
-static struct attribute *zcache_attrs[] = {
- &zcache_curr_obj_count_attr.attr,
- &zcache_curr_obj_count_max_attr.attr,
- &zcache_curr_objnode_count_attr.attr,
- &zcache_curr_objnode_count_max_attr.attr,
- &zcache_flush_total_attr.attr,
- &zcache_flobj_total_attr.attr,
- &zcache_flush_found_attr.attr,
- &zcache_flobj_found_attr.attr,
- &zcache_failed_eph_puts_attr.attr,
- &zcache_failed_pers_puts_attr.attr,
- &zcache_compress_poor_attr.attr,
- &zcache_mean_compress_poor_attr.attr,
- &zcache_zbud_curr_raw_pages_attr.attr,
- &zcache_zbud_curr_zpages_attr.attr,
- &zcache_zbud_curr_zbytes_attr.attr,
- &zcache_zbud_cumul_zpages_attr.attr,
- &zcache_zbud_cumul_zbytes_attr.attr,
- &zcache_zbud_buddied_count_attr.attr,
- &zcache_zbpg_unused_list_count_attr.attr,
- &zcache_evicted_raw_pages_attr.attr,
- &zcache_evicted_unbuddied_pages_attr.attr,
- &zcache_evicted_buddied_pages_attr.attr,
- &zcache_failed_get_free_pages_attr.attr,
- &zcache_failed_alloc_attr.attr,
- &zcache_put_to_flush_attr.attr,
- &zcache_aborted_preload_attr.attr,
- &zcache_aborted_shrink_attr.attr,
- &zcache_zbud_unbuddied_list_counts_attr.attr,
- &zcache_zbud_cumul_chunk_counts_attr.attr,
- &zcache_zv_curr_dist_counts_attr.attr,
- &zcache_zv_cumul_dist_counts_attr.attr,
- &zcache_zv_max_zsize_attr.attr,
- &zcache_zv_max_mean_zsize_attr.attr,
- &zcache_zv_page_count_policy_percent_attr.attr,
- NULL,
-};
-
-static struct attribute_group zcache_attr_group = {
- .attrs = zcache_attrs,
- .name = "zcache",
-};
-
-#endif /* CONFIG_SYSFS */
-/*
- * When zcache is disabled ("frozen"), pools can be created and destroyed,
- * but all puts (and thus all other operations that require memory allocation)
- * must fail. If zcache is unfrozen, accepts puts, then frozen again,
- * data consistency requires all puts while frozen to be converted into
- * flushes.
- */
-static bool zcache_freeze;
-
-/*
- * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
- */
-static int shrink_zcache_memory(struct shrinker *shrink,
- struct shrink_control *sc)
-{
- int ret = -1;
- int nr = sc->nr_to_scan;
- gfp_t gfp_mask = sc->gfp_mask;
-
- if (nr >= 0) {
- if (!(gfp_mask & __GFP_FS))
- /* does this case really need to be skipped? */
- goto out;
- if (spin_trylock(&zcache_direct_reclaim_lock)) {
- zbud_evict_pages(nr);
- spin_unlock(&zcache_direct_reclaim_lock);
- } else
- zcache_aborted_shrink++;
- }
- ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
-out:
- return ret;
-}
-
-static struct shrinker zcache_shrinker = {
- .shrink = shrink_zcache_memory,
- .seeks = DEFAULT_SEEKS,
-};
-
-/*
- * zcache shims between cleancache/frontswap ops and tmem
- */
-
-static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
- uint32_t index, struct page *page)
-{
- struct tmem_pool *pool;
- int ret = -1;
-
- BUG_ON(!irqs_disabled());
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (unlikely(pool == NULL))
- goto out;
- if (!zcache_freeze && zcache_do_preload(pool) == 0) {
- /* preload does preempt_disable on success */
- ret = tmem_put(pool, oidp, index, page_address(page),
- PAGE_SIZE, 0, is_ephemeral(pool));
- if (ret < 0) {
- if (is_ephemeral(pool))
- zcache_failed_eph_puts++;
- else
- zcache_failed_pers_puts++;
- }
- zcache_put_pool(pool);
- preempt_enable_no_resched();
- } else {
- zcache_put_to_flush++;
- if (atomic_read(&pool->obj_count) > 0)
- /* the put fails whether the flush succeeds or not */
- (void)tmem_flush_page(pool, oidp, index);
- zcache_put_pool(pool);
- }
-out:
- return ret;
-}
-
-static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
- uint32_t index, struct page *page)
-{
- struct tmem_pool *pool;
- int ret = -1;
- unsigned long flags;
- size_t size = PAGE_SIZE;
-
- local_irq_save(flags);
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (likely(pool != NULL)) {
- if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_get(pool, oidp, index, page_address(page),
- &size, 0, is_ephemeral(pool));
- zcache_put_pool(pool);
- }
- local_irq_restore(flags);
- return ret;
-}
-
-static int zcache_flush_page(int cli_id, int pool_id,
- struct tmem_oid *oidp, uint32_t index)
-{
- struct tmem_pool *pool;
- int ret = -1;
- unsigned long flags;
-
- local_irq_save(flags);
- zcache_flush_total++;
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (likely(pool != NULL)) {
- if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_flush_page(pool, oidp, index);
- zcache_put_pool(pool);
- }
- if (ret >= 0)
- zcache_flush_found++;
- local_irq_restore(flags);
- return ret;
-}
-
-static int zcache_flush_object(int cli_id, int pool_id,
- struct tmem_oid *oidp)
-{
- struct tmem_pool *pool;
- int ret = -1;
- unsigned long flags;
-
- local_irq_save(flags);
- zcache_flobj_total++;
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (likely(pool != NULL)) {
- if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_flush_object(pool, oidp);
- zcache_put_pool(pool);
- }
- if (ret >= 0)
- zcache_flobj_found++;
- local_irq_restore(flags);
- return ret;
-}
-
-static int zcache_destroy_pool(int cli_id, int pool_id)
-{
- struct tmem_pool *pool = NULL;
- struct zcache_client *cli = NULL;
- int ret = -1;
-
- if (pool_id < 0)
- goto out;
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else if ((unsigned int)cli_id < MAX_CLIENTS)
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- atomic_inc(&cli->refcount);
- pool = cli->tmem_pools[pool_id];
- if (pool == NULL)
- goto out;
- cli->tmem_pools[pool_id] = NULL;
- /* wait for pool activity on other cpus to quiesce */
- while (atomic_read(&pool->refcount) != 0)
- ;
- atomic_dec(&cli->refcount);
- local_bh_disable();
- ret = tmem_destroy_pool(pool);
- local_bh_enable();
- kfree(pool);
- pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
- pool_id, cli_id);
-out:
- return ret;
-}
-
-static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
-{
- int poolid = -1;
- struct tmem_pool *pool;
- struct zcache_client *cli = NULL;
-
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else if ((unsigned int)cli_id < MAX_CLIENTS)
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- atomic_inc(&cli->refcount);
- pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
- if (pool == NULL) {
- pr_info("zcache: pool creation failed: out of memory\n");
- goto out;
- }
-
- for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
- if (cli->tmem_pools[poolid] == NULL)
- break;
- if (poolid >= MAX_POOLS_PER_CLIENT) {
- pr_info("zcache: pool creation failed: max exceeded\n");
- kfree(pool);
- poolid = -1;
- goto out;
- }
- atomic_set(&pool->refcount, 0);
- pool->client = cli;
- pool->pool_id = poolid;
- tmem_new_pool(pool, flags);
- cli->tmem_pools[poolid] = pool;
- pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
- flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
- poolid, cli_id);
-out:
- if (cli != NULL)
- atomic_dec(&cli->refcount);
- return poolid;
-}
-
-/**********
- * Two kernel functionalities currently can be layered on top of tmem.
- * These are "cleancache" which is used as a second-chance cache for clean
- * page cache pages; and "frontswap" which is used for swap pages
- * to avoid writes to disk. A generic "shim" is provided here for each
- * to translate in-kernel semantics to zcache semantics.
- */
-
-#ifdef CONFIG_CLEANCACHE
-static void zcache_cleancache_put_page(int pool_id,
- struct cleancache_filekey key,
- pgoff_t index, struct page *page)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (likely(ind == index))
- (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
-}
-
-static int zcache_cleancache_get_page(int pool_id,
- struct cleancache_filekey key,
- pgoff_t index, struct page *page)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
- int ret = -1;
-
- if (likely(ind == index))
- ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
- return ret;
-}
-
-static void zcache_cleancache_flush_page(int pool_id,
- struct cleancache_filekey key,
- pgoff_t index)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (likely(ind == index))
- (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
-}
-
-static void zcache_cleancache_flush_inode(int pool_id,
- struct cleancache_filekey key)
-{
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
-}
-
-static void zcache_cleancache_flush_fs(int pool_id)
-{
- if (pool_id >= 0)
- (void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
-}
-
-static int zcache_cleancache_init_fs(size_t pagesize)
-{
- BUG_ON(sizeof(struct cleancache_filekey) !=
- sizeof(struct tmem_oid));
- BUG_ON(pagesize != PAGE_SIZE);
- return zcache_new_pool(LOCAL_CLIENT, 0);
-}
-
-static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
-{
- /* shared pools are unsupported and map to private */
- BUG_ON(sizeof(struct cleancache_filekey) !=
- sizeof(struct tmem_oid));
- BUG_ON(pagesize != PAGE_SIZE);
- return zcache_new_pool(LOCAL_CLIENT, 0);
-}
-
-static struct cleancache_ops zcache_cleancache_ops = {
- .put_page = zcache_cleancache_put_page,
- .get_page = zcache_cleancache_get_page,
- .flush_page = zcache_cleancache_flush_page,
- .flush_inode = zcache_cleancache_flush_inode,
- .flush_fs = zcache_cleancache_flush_fs,
- .init_shared_fs = zcache_cleancache_init_shared_fs,
- .init_fs = zcache_cleancache_init_fs
-};
-
-struct cleancache_ops zcache_cleancache_register_ops(void)
-{
- struct cleancache_ops old_ops =
- cleancache_register_ops(&zcache_cleancache_ops);
-
- return old_ops;
-}
-#endif
-
-#ifdef CONFIG_FRONTSWAP
-/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
-static int zcache_frontswap_poolid = -1;
-
-/*
- * Swizzling increases objects per swaptype, increasing tmem concurrency
- * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
- */
-#define SWIZ_BITS 4
-#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
-#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
-#define iswiz(_ind) (_ind >> SWIZ_BITS)
-
-static inline struct tmem_oid oswiz(unsigned type, u32 ind)
-{
- struct tmem_oid oid = { .oid = { 0 } };
- oid.oid[0] = _oswiz(type, ind);
- return oid;
-}
-
-static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
- struct page *page)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- struct tmem_oid oid = oswiz(type, ind);
- int ret = -1;
- unsigned long flags;
-
- BUG_ON(!PageLocked(page));
- if (likely(ind64 == ind)) {
- local_irq_save(flags);
- ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
- &oid, iswiz(ind), page);
- local_irq_restore(flags);
- }
- return ret;
-}
-
-/* returns 0 if the page was successfully gotten from frontswap, -1 if
- * was not present (should never happen!) */
-static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
- struct page *page)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- struct tmem_oid oid = oswiz(type, ind);
- int ret = -1;
-
- BUG_ON(!PageLocked(page));
- if (likely(ind64 == ind))
- ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
- &oid, iswiz(ind), page);
- return ret;
-}
-
-/* flush a single page from frontswap */
-static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- struct tmem_oid oid = oswiz(type, ind);
-
- if (likely(ind64 == ind))
- (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
- &oid, iswiz(ind));
-}
-
-/* flush all pages from the passed swaptype */
-static void zcache_frontswap_flush_area(unsigned type)
-{
- struct tmem_oid oid;
- int ind;
-
- for (ind = SWIZ_MASK; ind >= 0; ind--) {
- oid = oswiz(type, ind);
- (void)zcache_flush_object(LOCAL_CLIENT,
- zcache_frontswap_poolid, &oid);
- }
-}
-
-static void zcache_frontswap_init(unsigned ignored)
-{
- /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
- if (zcache_frontswap_poolid < 0)
- zcache_frontswap_poolid =
- zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
-}
-
-static struct frontswap_ops zcache_frontswap_ops = {
- .put_page = zcache_frontswap_put_page,
- .get_page = zcache_frontswap_get_page,
- .flush_page = zcache_frontswap_flush_page,
- .flush_area = zcache_frontswap_flush_area,
- .init = zcache_frontswap_init
-};
-
-struct frontswap_ops zcache_frontswap_register_ops(void)
-{
- struct frontswap_ops old_ops =
- frontswap_register_ops(&zcache_frontswap_ops);
-
- return old_ops;
-}
-#endif
-
-/*
- * zcache initialization
- * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
- * NOTHING HAPPENS!
- */
-
-static int zcache_enabled;
-
-static int __init enable_zcache(char *s)
-{
- zcache_enabled = 1;
- return 1;
-}
-__setup("zcache", enable_zcache);
-
-/* allow independent dynamic disabling of cleancache and frontswap */
-
-static int use_cleancache = 1;
-
-static int __init no_cleancache(char *s)
-{
- use_cleancache = 0;
- return 1;
-}
-
-__setup("nocleancache", no_cleancache);
-
-static int use_frontswap = 1;
-
-static int __init no_frontswap(char *s)
-{
- use_frontswap = 0;
- return 1;
-}
-
-__setup("nofrontswap", no_frontswap);
-
-static int __init zcache_init(void)
-{
-#ifdef CONFIG_SYSFS
- int ret = 0;
-
- ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
- if (ret) {
- pr_err("zcache: can't create sysfs\n");
- goto out;
- }
-#endif /* CONFIG_SYSFS */
-#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
- if (zcache_enabled) {
- unsigned int cpu;
-
- tmem_register_hostops(&zcache_hostops);
- tmem_register_pamops(&zcache_pamops);
- ret = register_cpu_notifier(&zcache_cpu_notifier_block);
- if (ret) {
- pr_err("zcache: can't register cpu notifier\n");
- goto out;
- }
- for_each_online_cpu(cpu) {
- void *pcpu = (void *)(long)cpu;
- zcache_cpu_notifier(&zcache_cpu_notifier_block,
- CPU_UP_PREPARE, pcpu);
- }
- }
- zcache_objnode_cache = kmem_cache_create("zcache_objnode",
- sizeof(struct tmem_objnode), 0, 0, NULL);
- zcache_obj_cache = kmem_cache_create("zcache_obj",
- sizeof(struct tmem_obj), 0, 0, NULL);
- ret = zcache_new_client(LOCAL_CLIENT);
- if (ret) {
- pr_err("zcache: can't create client\n");
- goto out;
- }
-#endif
-#ifdef CONFIG_CLEANCACHE
- if (zcache_enabled && use_cleancache) {
- struct cleancache_ops old_ops;
-
- zbud_init();
- register_shrinker(&zcache_shrinker);
- old_ops = zcache_cleancache_register_ops();
- pr_info("zcache: cleancache enabled using kernel "
- "transcendent memory and compression buddies\n");
- if (old_ops.init_fs != NULL)
- pr_warning("zcache: cleancache_ops overridden");
- }
-#endif
-#ifdef CONFIG_FRONTSWAP
- if (zcache_enabled && use_frontswap) {
- struct frontswap_ops old_ops;
-
- old_ops = zcache_frontswap_register_ops();
- pr_info("zcache: frontswap enabled using kernel "
- "transcendent memory and xvmalloc\n");
- if (old_ops.init != NULL)
- pr_warning("ktmem: frontswap_ops overridden");
- }
-#endif
-out:
- return ret;
-}
-
-module_init(zcache_init)
projects / cascardo / linux.git / commitdiff