The patch titled
Subject: mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh-v2
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh-v2.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh-v2.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh-v2
Date: Thu, 11 Jan 2024 14:28:07 -0500
also handle the case when tasks are being killed during the reclaim
Link: https://lkml.kernel.org/r/20240111192807.GA424308@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Dan Schatzberg <schatzberg.dan@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 37 ++++++++++++++++++++-----------------
1 file changed, 20 insertions(+), 17 deletions(-)
--- a/mm/memcontrol.c~mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh-v2
+++ a/mm/memcontrol.c
@@ -2624,8 +2624,8 @@ static unsigned long calculate_high_dela
/*
* Reclaims memory over the high limit. Called directly from
- * try_charge() when possible, but also scheduled to be called from
- * the userland return path where reclaim is always able to block.
+ * try_charge() (context permitting), as well as from the userland
+ * return path where reclaim is always able to block.
*/
void mem_cgroup_handle_over_high(gfp_t gfp_mask)
{
@@ -2645,6 +2645,17 @@ void mem_cgroup_handle_over_high(gfp_t g
retry_reclaim:
/*
+ * Bail if the task is already exiting. Unlike memory.max,
+ * memory.high enforcement isn't as strict, and there is no
+ * OOM killer involved, which means the excess could already
+ * be much bigger (and still growing) than it could for
+ * memory.max; the dying task could get stuck in fruitless
+ * reclaim for a long time, which isn't desirable.
+ */
+ if (task_is_dying())
+ goto out;
+
+ /*
* The allocating task should reclaim at least the batch size, but for
* subsequent retries we only want to do what's necessary to prevent oom
* or breaching resource isolation.
@@ -2892,24 +2903,16 @@ done_restock:
} while ((memcg = parent_mem_cgroup(memcg)));
/*
- * Reclaim is scheduled for the userland return path already,
- * but also attempt synchronous reclaim to avoid excessive
- * overrun while the task is still inside the kernel. If this
- * is successful, the return path will see it when it rechecks
- * the overage, and simply bail out.
- *
- * Skip if the task is already dying, though. Unlike
- * memory.max, memory.high enforcement isn't as strict, and
- * there is no OOM killer involved, which means the excess
- * could already be much bigger (and still growing) than it
- * could for memory.max; the dying task could get stuck in
- * fruitless reclaim for a long time, which isn't desirable.
+ * Reclaim is set up above to be called from the userland
+ * return path. But also attempt synchronous reclaim to avoid
+ * excessive overrun while the task is still inside the
+ * kernel. If this is successful, the return path will see it
+ * when it rechecks the overage and simply bail out.
*/
if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH &&
- !(current->flags & PF_MEMALLOC) && !task_is_dying() &&
- gfpflags_allow_blocking(gfp_mask)) {
+ !(current->flags & PF_MEMALLOC) &&
+ gfpflags_allow_blocking(gfp_mask))
mem_cgroup_handle_over_high(gfp_mask);
- }
return 0;
}
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh.patch
mm-memcontrol-dont-throttle-dying-tasks-on-memoryhigh-v2.patch
