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| 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 /lib/dec_and_lock.c | |
| parent | bd6daba909d8484bd2ccf6017db4028d7a420927 (diff) | |
| download | blackbird-op-linux-e767e0561d7fd2333df1921f1ab4176211f9036b.tar.gz blackbird-op-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 'lib/dec_and_lock.c')
0 files changed, 0 insertions, 0 deletions
