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mm-memcg-dump-memcg-protection-info-on-oom-or-alloc-failures.patch removed from -mm tree

merged mm-stable Andrew Morton 1 participant 1 message Nov 20, 2025

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The quilt patch titled
Subject: mm: memcg: dump memcg protection info on oom or alloc failures
has been removed from the -mm tree. Its filename was
mm-memcg-dump-memcg-protection-info-on-oom-or-alloc-failures.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Shakeel Butt <[email protected]>
Subject: mm: memcg: dump memcg protection info on oom or alloc failures
Date: Fri, 7 Nov 2025 15:40:41 -0800

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/[email protected] open here
Signed-off-by Shakeel Butt <[email protected]>
Acked-by Vlastimil Babka <[email protected]>
Acked-by Michal Hocko <[email protected]>
Cc Roman Gushchin <[email protected]>
Cc Johannes Weiner <[email protected]>
Cc Shakeel Butt <[email protected]>
Cc Muchun Song <[email protected]>
Cc David Rientjes <[email protected]>
Signed-off-by Andrew Morton <[email protected]>

---

 include/linux/memcontrol.h |    5 +++++
 mm/memcontrol.c            |   13 +++++++++++++
 mm/oom_kill.c              |    1 +
 mm/page_alloc.c            |    1 +
 4 files changed, 20 insertions(+)
include/linux/memcontrol.h renamed from include/linux/memcontrol.h~mm-memcg-dump-memcg-protection-info-on-oom-or-alloc-failures +5 -0
@@ -1764,6 +1764,7 @@ static inline void count_objcg_events(st
 
 bool mem_cgroup_node_allowed(struct mem_cgroup *memcg, int nid);
 
+void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg);
 #else
 static inline bool mem_cgroup_kmem_disabled(void)
 {

@@ -1830,6 +1831,10 @@ static inline bool mem_cgroup_node_allow
 {
 	return true;
 }
+
+static inline void mem_cgroup_show_protected_memory(struct mem_cgroup *memcg)
+{
+}
 #endif /* CONFIG_MEMCG */
 
 #if defined(CONFIG_MEMCG) && defined(CONFIG_ZSWAP)
mm/memcontrol.c renamed from mm/memcontrol.c~mm-memcg-dump-memcg-protection-info-on-oom-or-alloc-failures +13 -0
@@ -5635,3 +5635,16 @@ bool mem_cgroup_node_allowed(struct mem_
 {
 	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));
+}
mm/oom_kill.c renamed from mm/oom_kill.c~mm-memcg-dump-memcg-protection-info-on-oom-or-alloc-failures +1 -0
@@ -472,6 +472,7 @@ static void dump_header(struct oom_contr
 		if (should_dump_unreclaim_slab())
 			dump_unreclaimable_slab();
 	}
+	mem_cgroup_show_protected_memory(oc->memcg);
 	if (sysctl_oom_dump_tasks)
 		dump_tasks(oc);
 }
mm/page_alloc.c renamed from mm/page_alloc.c~mm-memcg-dump-memcg-protection-info-on-oom-or-alloc-failures +1 -0
@@ -3977,6 +3977,7 @@ static void warn_alloc_show_mem(gfp_t gf
 		filter &= ~SHOW_MEM_FILTER_NODES;
 
 	__show_mem(filter, nodemask, gfp_zone(gfp_mask));
+	mem_cgroup_show_protected_memory(NULL);
 }
 
 void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)

_

Patches currently in -mm which might be from [email protected] are

memcg-use-mod_node_page_state-to-update-stats.patch memcg-remove-__mod_lruvec_kmem_state.patch memcg-remove-__mod_lruvec_state.patch memcg-remove-__lruvec_stat_mod_folio.patch