The patch titled
Subject: mm-kmem-add-direct-objcg-pointer-to-task_struct-v4
has been added to the -mm mm-unstable branch. Its filename is
mm-kmem-add-direct-objcg-pointer-to-task_struct-v4.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-kmem-add-direct-objcg-pointer-to-task_struct-v4.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: mm-kmem-add-direct-objcg-pointer-to-task_struct-v4
Date: Wed, 18 Oct 2023 11:08:20 -0700
add comment, s/0/CURRENT_OBJCG_UPDATE_BIT/
Link: https://lkml.kernel.org/r/ZTAfFOsvlbqPI0Uk@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@xxxxxxxxx>
Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/mm/memcontrol.c~mm-kmem-add-direct-objcg-pointer-to-task_struct-v4
+++ a/mm/memcontrol.c
@@ -249,7 +249,8 @@ struct mem_cgroup *vmpressure_to_memcg(s
return container_of(vmpr, struct mem_cgroup, vmpressure);
}
-#define CURRENT_OBJCG_UPDATE_FLAG 0x1UL
+#define CURRENT_OBJCG_UPDATE_BIT 0
+#define CURRENT_OBJCG_UPDATE_FLAG (1UL << CURRENT_OBJCG_UPDATE_BIT)
#ifdef CONFIG_MEMCG_KMEM
static DEFINE_SPINLOCK(objcg_lock);
@@ -3126,6 +3127,13 @@ static struct obj_cgroup *current_objcg_
old = NULL;
}
+ /*
+ * Release the objcg pointer from the previous iteration,
+ * if try_cmpxcg() below fails.
+ */
+ if (unlikely(objcg))
+ obj_cgroup_put(objcg);
+
/* Obtain the new objcg pointer. */
rcu_read_lock();
memcg = mem_cgroup_from_task(current);
@@ -6598,7 +6606,7 @@ static void mem_cgroup_kmem_attach(struc
cgroup_taskset_for_each(task, css, tset) {
/* atomically set the update bit */
- set_bit(0, (unsigned long *)&task->objcg);
+ set_bit(CURRENT_OBJCG_UPDATE_BIT, (unsigned long *)&task->objcg);
}
}
#else
_
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-add-direct-objcg-pointer-to-task_struct-v4.patch
mm-kmem-make-memcg-keep-a-reference-to-the-original-objcg.patch
mm-kmem-scoped-objcg-protection.patch
percpu-scoped-objcg-protection.patch
