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Date: Thu, 12 Jan 2017 14:46:34 -0800 (PST) From: David Rientjes <rientjes@...gle.com> To: Andrew Morton <akpm@...ux-foundation.org> cc: Johannes Weiner <hannes@...xchg.org>, Vladimir Davydov <vdavydov.dev@...il.com>, Michal Hocko <mhocko@...nel.org>, cgroups@...r.kernel.org, linux-kernel@...r.kernel.org, linux-mm@...ck.org Subject: [patch v2] mm, memcg: do not retry precharge charges 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. This can be allowed to do reclaim, but should not call the oom killer to oom kill a process. It's better to fail the attach rather than oom kill a process attached to the memcg hierarchy. 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") Signed-off-by: David Rientjes <rientjes@...gle.com> --- mm/memcontrol.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4353,9 +4353,12 @@ static int mem_cgroup_do_precharge(unsigned long count) return ret; } - /* Try charges one by one with reclaim */ + /* + * Try charges one by one with reclaim, but do not retry. This avoids + * calling the oom killer when the precharge should just fail. + */ 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; mc.precharge++;
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