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* [merged] mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch removed from -mm tree
@ 2020-08-10  2:37 akpm
  0 siblings, 0 replies; only message in thread
From: akpm @ 2020-08-10  2:37 UTC (permalink / raw)
  To: cl, guro, hannes, iamjoonsoo.kim, mhocko, mm-commits, penberg,
	rientjes, shakeelb, vbabka


The patch titled
     Subject: mm: kmem: switch to static_branch_likely() in memcg_kmem_enabled()
has been removed from the -mm tree.  Its filename was
     mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Roman Gushchin <guro@fb.com>
Subject: mm: kmem: switch to static_branch_likely() in memcg_kmem_enabled()

Currently memcg_kmem_enabled() is optimized for the kernel memory
accounting being off.  It was so for a long time, and arguably the reason
behind was that the kernel memory accounting was initially an opt-in
feature.  However, now it's on by default on both cgroup v1 and cgroup v2,
and it's on for all cgroups.  So let's switch over to
static_branch_likely() to reflect this fact.

Unlikely there is a significant performance difference, as the cost of a
memory allocation and its accounting significantly exceeds the cost of a
jump.  However, the conversion makes the code look more logically.

Link: http://lkml.kernel.org/r/20200707173612.124425-3-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memcontrol.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/memcontrol.h~mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled
+++ a/include/linux/memcontrol.h
@@ -1448,7 +1448,7 @@ void memcg_put_cache_ids(void);
 
 static inline bool memcg_kmem_enabled(void)
 {
-	return static_branch_unlikely(&memcg_kmem_enabled_key);
+	return static_branch_likely(&memcg_kmem_enabled_key);
 }
 
 static inline bool memcg_kmem_bypass(void)
_

Patches currently in -mm which might be from guro@fb.com are

percpu-return-number-of-released-bytes-from-pcpu_free_area.patch
mm-memcg-percpu-account-percpu-memory-to-memory-cgroups.patch
mm-memcg-percpu-per-memcg-percpu-memory-statistics.patch
mm-memcg-percpu-per-memcg-percpu-memory-statistics-v3.patch
mm-memcg-charge-memcg-percpu-memory-to-the-parent-cgroup.patch
kselftests-cgroup-add-perpcu-memory-accounting-test.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix.patch


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2020-08-10  2:37 [merged] mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch removed from -mm tree akpm

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