diff options
| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2009-05-28 14:34:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-05-29 08:40:02 -0700 |
| commit | e767e0561d7fd2333df1921f1ab4176211f9036b (patch) | |
| tree | 3b936733f80ceb1ee61ce99f927d002d2296250e /mm/filemap.c | |
| parent | bd6daba909d8484bd2ccf6017db4028d7a420927 (diff) | |
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/filemap.c')
| -rw-r--r-- | mm/filemap.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 379ff0bcbf6e..1b60f30cebfa 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -121,7 +121,6 @@ void __remove_from_page_cache(struct page *page) mapping->nrpages--; __dec_zone_page_state(page, NR_FILE_PAGES); BUG_ON(page_mapped(page)); - mem_cgroup_uncharge_cache_page(page); /* * Some filesystems seem to re-dirty the page even after @@ -145,6 +144,7 @@ void remove_from_page_cache(struct page *page) spin_lock_irq(&mapping->tree_lock); __remove_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_cache_page(page); } static int sync_page(void *word) @@ -476,13 +476,13 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping, if (likely(!error)) { mapping->nrpages++; __inc_zone_page_state(page, NR_FILE_PAGES); + spin_unlock_irq(&mapping->tree_lock); } else { page->mapping = NULL; + spin_unlock_irq(&mapping->tree_lock); mem_cgroup_uncharge_cache_page(page); page_cache_release(page); } - - spin_unlock_irq(&mapping->tree_lock); radix_tree_preload_end(); } else mem_cgroup_uncharge_cache_page(page); |