bcache: Kill bucket->gc_gen

gc_gen was a temporary used to recalculate last_gc, but since we only need
bucket->last_gc when gc isn't running (gc_mark_valid = 1), we can just update
last_gc directly.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 200efc1..82c9c5d 100644 (file)
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -196,7 +196,6 @@ struct bucket {
        uint16_t        prio;
        uint8_t         gen;
        uint8_t         last_gc; /* Most out of date gen in the btree */
-       uint8_t         gc_gen;
        uint16_t        gc_mark; /* Bitfield used by GC. See below for field */
 };
 
@@ -588,7 +587,7 @@ struct cache_set {
        uint16_t                min_prio;
 
        /*
-        * max(gen - gc_gen) for all buckets. When it gets too big we have to gc
+        * max(gen - last_gc) for all buckets. When it gets too big we have to gc
         * to keep gens from wrapping around.
         */
        uint8_t                 need_gc;

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 4c340c8..7347b61 100644 (file)
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1178,8 +1178,8 @@ static uint8_t __bch_btree_mark_key(struct cache_set *c, int level,
 
                g = PTR_BUCKET(c, k, i);
 
-               if (gen_after(g->gc_gen, PTR_GEN(k, i)))
-                       g->gc_gen = PTR_GEN(k, i);
+               if (gen_after(g->last_gc, PTR_GEN(k, i)))
+                       g->last_gc = PTR_GEN(k, i);
 
                if (ptr_stale(c, k, i)) {
                        stale = max(stale, ptr_stale(c, k, i));
@@ -1631,7 +1631,7 @@ static void btree_gc_start(struct cache_set *c)
 
        for_each_cache(ca, c, i)
                for_each_bucket(b, ca) {
-                       b->gc_gen = b->gen;
+                       b->last_gc = b->gen;
                        if (!atomic_read(&b->pin)) {
                                SET_GC_MARK(b, 0);
                                SET_GC_SECTORS_USED(b, 0);
@@ -1693,7 +1693,6 @@ static size_t bch_btree_gc_finish(struct cache_set *c)
                        SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
 
                for_each_bucket(b, ca) {
-                       b->last_gc      = b->gc_gen;
                        c->need_gc      = max(c->need_gc, bucket_gc_gen(b));
 
                        if (atomic_read(&b->pin))

diff --git a/drivers/md/bcache/extents.c b/drivers/md/bcache/extents.c
index 82d5e32..3588733 100644 (file)
--- a/drivers/md/bcache/extents.c
+++ b/drivers/md/bcache/extents.c
@@ -194,9 +194,9 @@ err:
        mutex_unlock(&b->c->bucket_lock);
        bch_extent_to_text(buf, sizeof(buf), k);
        btree_bug(b,
-"inconsistent btree pointer %s: bucket %zi pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
+"inconsistent btree pointer %s: bucket %zi pin %i prio %i gen %i last_gc %i mark %llu",
                  buf, PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
-                 g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
+                 g->prio, g->gen, g->last_gc, GC_MARK(g));
        return true;
 }
 
@@ -515,9 +515,9 @@ err:
        mutex_unlock(&b->c->bucket_lock);
        bch_extent_to_text(buf, sizeof(buf), k);
        btree_bug(b,
-"inconsistent extent pointer %s:\nbucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
+"inconsistent extent pointer %s:\nbucket %zu pin %i prio %i gen %i last_gc %i mark %llu",
                  buf, PTR_BUCKET_NR(b->c, k, ptr), atomic_read(&g->pin),
-                 g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
+                 g->prio, g->gen, g->last_gc, GC_MARK(g));
        return true;
 }
 

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index a8c57d5..926ded8 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -635,7 +635,7 @@ static void prio_read(struct cache *ca, uint64_t bucket)
                }
 
                b->prio = le16_to_cpu(d->prio);
-               b->gen = b->last_gc = b->gc_gen = d->gen;
+               b->gen = b->last_gc = d->gen;
        }
 }