diff options
| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2009-05-28 23:34:28 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-05-29 17:40:02 +0200 |
| commit | e767e0561d7fd2333df1921f1ab4176211f9036b (patch) | |
| tree | 3b936733f80ceb1ee61ce99f927d002d2296250e /mm/swap_state.c | |
| parent | procfs: make errno values consistent when open pident vs exit(2) race occurs (diff) | |
| download | linux-e767e0561d7fd2333df1921f1ab4176211f9036b.tar.xz linux-e767e0561d7fd2333df1921f1ab4176211f9036b.zip | |
memcg: fix deadlock between lock_page_cgroup and mapping tree_lock
mapping->tree_lock can be acquired from interrupt context. Then,
following dead lock can occur.
Assume "A" as a page.
CPU0:
lock_page_cgroup(A)
interrupted
-> take mapping->tree_lock.
CPU1:
take mapping->tree_lock
-> lock_page_cgroup(A)
This patch tries to fix above deadlock by moving memcg's hook to out of
mapping->tree_lock. charge/uncharge of pagecache/swapcache is protected
by page lock, not tree_lock.
After this patch, lock_page_cgroup() is not called under mapping->tree_lock.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swap_state.c')
| -rw-r--r-- | mm/swap_state.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index 3ecea98ecb45..1416e7e9e02d 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -109,8 +109,6 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) */ void __delete_from_swap_cache(struct page *page) { - swp_entry_t ent = {.val = page_private(page)}; - VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(!PageSwapCache(page)); VM_BUG_ON(PageWriteback(page)); @@ -121,7 +119,6 @@ void __delete_from_swap_cache(struct page *page) total_swapcache_pages--; __dec_zone_page_state(page, NR_FILE_PAGES); INC_CACHE_INFO(del_total); - mem_cgroup_uncharge_swapcache(page, ent); } /** @@ -191,6 +188,7 @@ void delete_from_swap_cache(struct page *page) __delete_from_swap_cache(page); spin_unlock_irq(&swapper_space.tree_lock); + mem_cgroup_uncharge_swapcache(page, entry); swap_free(entry); page_cache_release(page); } |