+ mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches.patch added to -mm tree

+ mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: memcg/slab: disable cache merging for KMALLOC_NORMAL caches
has been added to the -mm tree.  Its filename is
     mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches.patch

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------------------------------------------------------
From: Waiman Long <longman@redhat.com>
Subject: mm: memcg/slab: disable cache merging for KMALLOC_NORMAL caches

The KMALLOC_NORMAL (kmalloc-<n>) caches are for unaccounted objects only
when CONFIG_MEMCG_KMEM is enabled.  To make sure that this condition
remains true, we will have to prevent KMALOC_NORMAL caches to merge with
other kmem caches.  This is now done by setting its refcount to -1 right
after its creation.

Link: https://lkml.kernel.org/r/20210505200610.13943-4-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Roman Gushchin <guro@fb.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/slab_common.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/mm/slab_common.c~mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches
+++ a/mm/slab_common.c
@@ -856,6 +856,13 @@ new_kmalloc_cache(int idx, enum kmalloc_
 					kmalloc_info[idx].name[type],
 					kmalloc_info[idx].size, flags, 0,
 					kmalloc_info[idx].size);
+
+	/*
+	 * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
+	 * KMALLOC_NORMAL caches.
+	 */
+	if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL))
+		kmalloc_caches[type][idx]->refcount = -1;
 }
 
 /*
_

Patches currently in -mm which might be from longman@redhat.com are

mm-memcg-move-mod_objcg_state-to-memcontrolc.patch
mm-memcg-cache-vmstat-data-in-percpu-memcg_stock_pcp.patch
mm-memcg-improve-refill_obj_stock-performance.patch
mm-memcg-optimize-user-context-object-stock-access.patch
mm-memcg-slab-properly-set-up-gfp-flags-for-objcg-pointer-array.patch
mm-memcg-slab-create-a-new-set-of-kmalloc-cg-n-caches.patch
mm-memcg-slab-disable-cache-merging-for-kmalloc_normal-caches.patch