The patch titled
Subject: percpu: scoped objcg protection
has been added to the -mm mm-unstable branch. Its filename is
percpu-scoped-objcg-protection.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/percpu-scoped-objcg-protection.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Subject: percpu: scoped objcg protection
Date: Thu, 19 Oct 2023 15:53:45 -0700
Similar to slab and kmem, switch to a scope-based protection of the objcg
pointer to avoid.
Link: https://lkml.kernel.org/r/20231019225346.1822282-6-roman.gushchin@xxxxxxxxx
Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@xxxxxxxxx>
Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/percpu.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
--- a/mm/percpu.c~percpu-scoped-objcg-protection
+++ a/mm/percpu.c
@@ -1628,14 +1628,12 @@ static bool pcpu_memcg_pre_alloc_hook(si
if (!memcg_kmem_online() || !(gfp & __GFP_ACCOUNT))
return true;
- objcg = get_obj_cgroup_from_current();
+ objcg = current_obj_cgroup();
if (!objcg)
return true;
- if (obj_cgroup_charge(objcg, gfp, pcpu_obj_full_size(size))) {
- obj_cgroup_put(objcg);
+ if (obj_cgroup_charge(objcg, gfp, pcpu_obj_full_size(size)))
return false;
- }
*objcgp = objcg;
return true;
@@ -1649,6 +1647,7 @@ static void pcpu_memcg_post_alloc_hook(s
return;
if (likely(chunk && chunk->obj_cgroups)) {
+ obj_cgroup_get(objcg);
chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg;
rcu_read_lock();
@@ -1657,7 +1656,6 @@ static void pcpu_memcg_post_alloc_hook(s
rcu_read_unlock();
} else {
obj_cgroup_uncharge(objcg, pcpu_obj_full_size(size));
- obj_cgroup_put(objcg);
}
}
_
Patches currently in -mm which might be from roman.gushchin@xxxxxxxxx are
mm-kmem-optimize-get_obj_cgroup_from_current.patch
mm-kmem-add-direct-objcg-pointer-to-task_struct.patch
mm-kmem-make-memcg-keep-a-reference-to-the-original-objcg.patch
mm-kmem-scoped-objcg-protection.patch
percpu-scoped-objcg-protection.patch
mm-kmem-reimplement-get_obj_cgroup_from_current.patch
