The patch titled
Subject: mm: kmem: switch to static_branch_likely() in memcg_kmem_enabled()
has been added to the -mm tree. Its filename is
mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch
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------------------------------------------------------
From: Roman Gushchin <guro@xxxxxx>
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@xxxxxx
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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
@@ -1456,7 +1456,7 @@ 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@xxxxxx are
mm-kmem-make-memcg_kmem_enabled-irreversible.patch
mm-memcg-factor-out-memcg-and-lruvec-level-changes-out-of-__mod_lruvec_state.patch
mm-memcg-prepare-for-byte-sized-vmstat-items.patch
mm-memcg-convert-vmstat-slab-counters-to-bytes.patch
mm-slub-implement-slub-version-of-obj_to_index.patch
mm-memcg-slab-obj_cgroup-api.patch
mm-memcg-slab-allocate-obj_cgroups-for-non-root-slab-pages.patch
mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects.patch
mm-memcg-slab-charge-individual-slab-objects-instead-of-pages.patch
mm-memcg-slab-deprecate-memorykmemslabinfo.patch
mm-memcg-slab-move-memcg_kmem_bypass-to-memcontrolh.patch
mm-memcg-slab-use-a-single-set-of-kmem_caches-for-all-accounted-allocations.patch
mm-memcg-slab-simplify-memcg-cache-creation.patch
mm-memcg-slab-remove-memcg_kmem_get_cache.patch
mm-memcg-slab-deprecate-slab_root_caches.patch
mm-memcg-slab-remove-redundant-check-in-memcg_accumulate_slabinfo.patch
mm-memcg-slab-use-a-single-set-of-kmem_caches-for-all-allocations.patch
kselftests-cgroup-add-kernel-memory-accounting-tests.patch
tools-cgroup-add-memcg_slabinfopy-tool.patch
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-memcg-slab-remove-unused-argument-by-charge_slab_page.patch
mm-slab-rename-uncharge_slab_page-to-unaccount_slab_page.patch
mm-kmem-switch-to-static_branch_likely-in-memcg_kmem_enabled.patch
