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authorDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>2009-05-28 14:34:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-05-29 08:40:02 -0700
commite767e0561d7fd2333df1921f1ab4176211f9036b (patch)
tree3b936733f80ceb1ee61ce99f927d002d2296250e /include
parentbd6daba909d8484bd2ccf6017db4028d7a420927 (diff)
downloadlinux-e767e0561d7fd2333df1921f1ab4176211f9036b.tar.gz
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 'include')
-rw-r--r--include/linux/swap.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 62d81435347..d476aad3ff5 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -437,6 +437,11 @@ static inline int mem_cgroup_cache_charge_swapin(struct page *page,
return 0;
}
+static inline void
+mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
+{
+}
+
#endif /* CONFIG_SWAP */
#endif /* __KERNEL__*/
#endif /* _LINUX_SWAP_H */