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authorShakeel Butt <shakeel.butt@linux.dev>2025-11-07 15:40:41 -0800
committerAndrew Morton <akpm@linux-foundation.org>2025-11-20 13:43:59 -0800
commitbc8e51c05ad50a5a0b02114d3cc94d151a332595 (patch)
treef4fb70d09c8fd6a0ada55921d0a7b58d1c065cb8 /mm/memcontrol.c
parent05be0287955970b043a0742e85b6c285dea4f286 (diff)
mm: memcg: dump memcg protection info on oom or alloc failures
Currently kernel dumps memory state on oom and allocation failures. One of the question usually raised on those dumps is why the kernel has not reclaimed the reclaimable memory instead of triggering oom. One potential reason is the usage of memory protection provided by memcg. So, let's also dump the memory protected by the memcg in such reports to ease the debugging. Link: https://lkml.kernel.org/r/20251107234041.3632644-1-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 025da46d9959..bfc986da3289 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5635,3 +5635,16 @@ bool mem_cgroup_node_allowed(struct mem_cgroup *memcg, int nid)
{
return memcg ? cpuset_node_allowed(memcg->css.cgroup, nid) : true;
}
+
+void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg)
+{
+ if (mem_cgroup_disabled() || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return;
+
+ if (!memcg)
+ memcg = root_mem_cgroup;
+
+ pr_warn("Memory cgroup min protection %lukB -- low protection %lukB",
+ K(atomic_long_read(&memcg->memory.children_min_usage)*PAGE_SIZE),
+ K(atomic_long_read(&memcg->memory.children_low_usage)*PAGE_SIZE));
+}