From: Rabin Vincent <rabinv@xxxxxxxx>
Subject: mm: prevent NR_ISOLATE_* stats from going negative
Commit 6afcf8ef0ca0 ("mm, compaction: fix NR_ISOLATED_* stats for pfn
based migration") moved the dec_node_page_state() call (along with the
page_is_file_cache() call) to after putback_lru_page(). But
page_is_file_cache() can change after putback_lru_page() is called, so it
should be called before putback_lru_page(), as it was before that patch,
to prevent NR_ISOLATE_* stats from going negative.
Without this fix, non-CONFIG_SMP kernels end up hanging in the
while(too_many_isolated()) { congestion_wait() } loop in
shrink_active_list() due to the negative stats.
Mem-Info:
active_anon:32567 inactive_anon:121 isolated_anon:1
active_file:6066 inactive_file:6639 isolated_file:4294967295
^^^^^^^^^^
unevictable:0 dirty:115 writeback:0 unstable:0
slab_reclaimable:2086 slab_unreclaimable:3167
mapped:3398 shmem:18366 pagetables:1145 bounce:0
free:1798 free_pcp:13 free_cma:0
Fixes: 6afcf8ef0ca0 ("mm, compaction: fix NR_ISOLATED_* stats for pfn based migration")
Link: http://lkml.kernel.org/r/1492683865-27549-1-git-send-email-rabin.vincent@xxxxxxxx
Signed-off-by: Rabin Vincent <rabinv@xxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Ming Ling <ming.ling@xxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/migrate.c~mm-prevent-nr_isolate_-stats-from-going-negative mm/migrate.c
--- a/mm/migrate.c~mm-prevent-nr_isolate_-stats-from-going-negative
+++ a/mm/migrate.c
@@ -184,9 +184,9 @@ void putback_movable_pages(struct list_h
unlock_page(page);
put_page(page);
} else {
- putback_lru_page(page);
dec_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page));
+ putback_lru_page(page);
}
}
}
_