commit
9b7f43afd417a6feb80841d30ced4051c362eb5d upstream.
My
9ce70c0240d0 "memcg: fix deadlock by inverting lrucare nesting" put a
nasty little bug into v3.3's version of mem_cgroup_replace_page_cache(),
sometimes used for FUSE. Replacing __mem_cgroup_commit_charge_lrucare()
by __mem_cgroup_commit_charge(), I used the "pc" pointer set up earlier:
but it's for oldpage, and needs now to be for newpage. Once oldpage was
freed, its PageCgroupUsed bit (cleared above but set again here) caused
"Bad page state" messages - and perhaps worse, being missed from newpage.
(I didn't find this by using FUSE, but in reusing the function for tmpfs.)
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* the newpage may be on LRU(or pagevec for LRU) already. We lock
* LRU while we overwrite pc->mem_cgroup.
*/
+ pc = lookup_page_cgroup(newpage);
__mem_cgroup_commit_charge(memcg, newpage, 1, pc, type, true);
}