[PATCH 4.9 64/66] mm, memcg: do not retry precharge charges

From: Greg Kroah-Hartman
Date: Tue Jan 31 2017 - 00:56:15 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: David Rientjes <rientjes@xxxxxxxxxx>

commit 3674534b775354516e5c148ea48f51d4d1909a78 upstream.

When memory.move_charge_at_immigrate is enabled and precharges are
depleted during move, mem_cgroup_move_charge_pte_range() will attempt to
increase the size of the precharge.

Prevent precharges from ever looping by setting __GFP_NORETRY. This was
probably the intention of the GFP_KERNEL & ~__GFP_NORETRY, which is
pointless as written.

Fixes: 0029e19ebf84 ("mm: memcontrol: remove explicit OOM parameter in charge path")
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1701130208510.69402@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

mm/memcontrol.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4360,9 +4360,9 @@ static int mem_cgroup_do_precharge(unsig
return ret;

- /* Try charges one by one with reclaim */
+ /* Try charges one by one with reclaim, but do not retry */
while (count--) {
- ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
+ ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
if (ret)
return ret;