mm: use early_pfn_to_nid in page_ext_init

page_ext_init() checks suitable pages with pfn_to_nid(), but
pfn_to_nid() depends on memmap which will not be setup fully until
page_alloc_init_late() is done.  Use early_pfn_to_nid() instead of
pfn_to_nid() so that page extension could be still used early even
though CONFIG_ DEFERRED_STRUCT_PAGE_INIT is enabled and catch early page
allocation call sites.

Suggested by Joonsoo Kim [1], this fix basically undoes the change
introduced by commit b8f1a75d61d840 ("mm: call page_ext_init() after all
struct pages are initialized") and fixes the same problem with a better
approach.

[1] http://lkml.kernel.org/r/CAAmzW4OUmyPwQjvd7QUfc6W1Aic__TyAuH80MLRZNMxKy0-wPQ@mail.gmail.com

Link: http://lkml.kernel.org/r/1464198689-23458-1-git-send-email-yang.shi@linaro.org
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/init/main.c b/init/main.c
index bc0f9e0..4c17fda 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -607,6 +607,7 @@ asmlinkage __visible void __init start_kernel(void)
                initrd_start = 0;
        }
 #endif
+       page_ext_init();
        debug_objects_mem_init();
        kmemleak_init();
        setup_per_cpu_pageset();
@@ -1003,8 +1004,6 @@ static noinline void __init kernel_init_freeable(void)
        sched_init_smp();
 
        page_alloc_init_late();
-       /* Initialize page ext after all struct pages are initializaed */
-       page_ext_init();
 
        do_basic_setup();
 

diff --git a/mm/page_ext.c b/mm/page_ext.c
index 2d864e6..44a4c02 100644 (file)
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -390,8 +390,10 @@ void __init page_ext_init(void)
                         * We know some arch can have a nodes layout such as
                         * -------------pfn-------------->
                         * N0 | N1 | N2 | N0 | N1 | N2|....
+                        *
+                        * Take into account DEFERRED_STRUCT_PAGE_INIT.
                         */
-                       if (pfn_to_nid(pfn) != nid)
+                       if (early_pfn_to_nid(pfn) != nid)
                                continue;
                        if (init_section_page_ext(pfn, nid))
                                goto oom;