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@xxxxxxxxxx>
---
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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