[PATCH -mm] memcg: mem_cgroup_charge_statistics needs preempt_disable
From: Michal Hocko
Date: Fri Jun 20 2014 - 12:36:24 EST
preempt_disable was previously disabled by lock_page_cgroup which has
been removed by "mm: memcontrol: rewrite uncharge API".
This fixes the a flood of splats like this:
[ 3.149371] BUG: using __this_cpu_add() in preemptible [00000000] code: udevd/1271
[ 3.151458] caller is __this_cpu_preempt_check+0x13/0x15
[ 3.152927] CPU: 0 PID: 1271 Comm: udevd Not tainted 3.15.0-test1 #366
[ 3.154637] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[ 3.156788] 0000000000000000 ffff88000005fba8 ffffffff814efe3f 0000000000000000
[ 3.158810] ffff88000005fbd8 ffffffff8125b969 ffff880007413448 0000000000000001
[ 3.160836] ffffea00001e8c00 0000000000000001 ffff88000005fbe8 ffffffff8125b9a8
[ 3.162950] Call Trace:
[ 3.163598] [<ffffffff814efe3f>] dump_stack+0x4e/0x7a
[ 3.164942] [<ffffffff8125b969>] check_preemption_disabled+0xd2/0xe5
[ 3.166618] [<ffffffff8125b9a8>] __this_cpu_preempt_check+0x13/0x15
[ 3.168267] [<ffffffff8112b630>] mem_cgroup_charge_statistics.isra.36+0xb5/0xc6
[ 3.170169] [<ffffffff8112d2c5>] commit_charge+0x23c/0x256
[ 3.171823] [<ffffffff8113101b>] mem_cgroup_commit_charge+0xb8/0xd7
[ 3.173838] [<ffffffff810f5dab>] shmem_getpage_gfp+0x399/0x605
[ 3.175363] [<ffffffff810f7456>] shmem_write_begin+0x3d/0x58
[ 3.176854] [<ffffffff810e1361>] generic_perform_write+0xbc/0x192
[ 3.178445] [<ffffffff8114a086>] ? file_update_time+0x34/0xac
[ 3.179952] [<ffffffff810e2ae4>] __generic_file_aio_write+0x2c0/0x300
[ 3.181655] [<ffffffff810e2b76>] generic_file_aio_write+0x52/0xbd
[ 3.183234] [<ffffffff81133944>] do_sync_write+0x59/0x78
[ 3.184630] [<ffffffff81133ea8>] vfs_write+0xc4/0x181
[ 3.185957] [<ffffffff81134801>] SyS_write+0x4a/0x91
[ 3.187258] [<ffffffff814fd30e>] tracesys+0xd0/0xd5
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
---
Andrew,
the changelog is quite modest but this should be folded into
mm-memcontrol-rewrite-uncharge-api.patch anyway. If you want a
regular patch, please let me know.
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 241cf4f91e24..cbf373085b6c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -904,6 +904,8 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
struct page *page,
int nr_pages)
{
+ preempt_disable();
+
/*
* Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
* counted as CACHE even if it's on ANON LRU.
@@ -928,6 +930,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
}
__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
+ preempt_enable();
}
unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
--
2.0.0
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