The patch titled
memcg: avoid oom-killing innocent task in case of use_hierarchy
has been added to the -mm tree. Its filename is
memcg-avoid-oom-killing-innocent-task-in-case-of-use_hierarchy.patch
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------------------------------------------------------
Subject: memcg: avoid oom-killing innocent task in case of use_hierarchy
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
task_in_mem_cgroup(), which is called by select_bad_process() to check
whether a task can be a candidate for being oom-killed from memcg's limit,
checks "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs
to).
But this check return true(it's false positive) when:
<some path>/aa use_hierarchy == 0 <- hitting limit
<some path>/aa/00 use_hierarchy == 1 <- the task belongs to
This leads to killing an innocent task in aa/00. This patch is a fix for
this bug. And this patch also fixes the arg for
mem_cgroup_print_oom_info(). We should print information of mem_cgroup
which the task being killed, not current, belongs to.
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 10 ++++++++--
mm/oom_kill.c | 13 +++++++------
2 files changed, 15 insertions(+), 8 deletions(-)
diff -puN mm/memcontrol.c~memcg-avoid-oom-killing-innocent-task-in-case-of-use_hierarchy mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-avoid-oom-killing-innocent-task-in-case-of-use_hierarchy
+++ a/mm/memcontrol.c
@@ -760,7 +760,13 @@ int task_in_mem_cgroup(struct task_struc
task_unlock(task);
if (!curr)
return 0;
- if (curr->use_hierarchy)
+ /*
+ * We should check use_hierarchy of "mem" not "curr". Because checking
+ * use_hierarchy of "curr" here make this function true if hierarchy is
+ * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
+ * hierarchy(even if use_hierarchy is disabled in "mem").
+ */
+ if (mem->use_hierarchy)
ret = css_is_ancestor(&curr->css, &mem->css);
else
ret = (curr == mem);
@@ -1009,7 +1015,7 @@ void mem_cgroup_print_oom_info(struct me
static char memcg_name[PATH_MAX];
int ret;
- if (!memcg)
+ if (!memcg || !p)
return;
diff -puN mm/oom_kill.c~memcg-avoid-oom-killing-innocent-task-in-case-of-use_hierarchy mm/oom_kill.c
--- a/mm/oom_kill.c~memcg-avoid-oom-killing-innocent-task-in-case-of-use_hierarchy
+++ a/mm/oom_kill.c
@@ -356,7 +356,8 @@ static void dump_tasks(const struct mem_
} while_each_thread(g, p);
}
-static void dump_header(gfp_t gfp_mask, int order, struct mem_cgroup *mem)
+static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
+ struct mem_cgroup *mem)
{
pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
"oom_adj=%d\n",
@@ -365,7 +366,7 @@ static void dump_header(gfp_t gfp_mask,
cpuset_print_task_mems_allowed(current);
task_unlock(current);
dump_stack();
- mem_cgroup_print_oom_info(mem, current);
+ mem_cgroup_print_oom_info(mem, p);
show_mem();
if (sysctl_oom_dump_tasks)
dump_tasks(mem);
@@ -440,7 +441,7 @@ static int oom_kill_process(struct task_
struct task_struct *c;
if (printk_ratelimit())
- dump_header(gfp_mask, order, mem);
+ dump_header(p, gfp_mask, order, mem);
/*
* If the task is already exiting, don't alarm the sysadmin or kill
@@ -576,7 +577,7 @@ retry:
/* Found nothing?!?! Either we hang forever, or we panic. */
if (!p) {
read_unlock(&tasklist_lock);
- dump_header(gfp_mask, order, NULL);
+ dump_header(NULL, gfp_mask, order, NULL);
panic("Out of memory and no killable processes...\n");
}
@@ -644,7 +645,7 @@ void out_of_memory(struct zonelist *zone
return;
if (sysctl_panic_on_oom == 2) {
- dump_header(gfp_mask, order, NULL);
+ dump_header(NULL, gfp_mask, order, NULL);
panic("out of memory. Compulsory panic_on_oom is selected.\n");
}
@@ -663,7 +664,7 @@ void out_of_memory(struct zonelist *zone
case CONSTRAINT_NONE:
if (sysctl_panic_on_oom) {
- dump_header(gfp_mask, order, NULL);
+ dump_header(NULL, gfp_mask, order, NULL);
panic("out of memory. panic_on_oom is selected\n");
}
/* Fall-through */
_
Patches currently in -mm which might be from nishimura@xxxxxxxxxxxxxxxxx are
oom-kill-fix-numa-consraint-check-with-nodemask-v42.patch
oom-kill-fix-numa-consraint-check-with-nodemask-v42-checkpatch-fixes.patch
memcg-coalesce-uncharge-during-unmap-truncate.patch
memcg-coalesce-charging-via-percpu-storage.patch
memcg-coalesce-charging-via-percpu-storage-fix.patch
memcg-coalesce-charging-via-percpu-storage-fix-2.patch
memcg-make-memcgs-file-mapped-consistent-with-global-vm.patch
memcg-add-mem_cgroup_cancel_charge.patch
memcg-cleanup-mem_cgroup_move_parent.patch
memcg-avoid-oom-killing-innocent-task-in-case-of-use_hierarchy.patch
memcg-remove-memcg_tasklist.patch
--
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