+ mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock.patch added to -mm tree

+ mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: memcontrol: move obj_cgroup_uncharge_pages() out of css_set_lock
has been added to the -mm tree.  Its filename is
     mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock.patch

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------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: memcontrol: move obj_cgroup_uncharge_pages() out of css_set_lock

The css_set_lock is used to guard the list of inherited objcgs.  So there
is no need to uncharge kernel memory under css_set_lock.  Just move it out
of the lock.

Link: https://lkml.kernel.org/r/20210417043538.9793-8-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/memcontrol.c~mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock
+++ a/mm/memcontrol.c
@@ -289,9 +289,10 @@ static void obj_cgroup_release(struct pe
 	WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1));
 	nr_pages = nr_bytes >> PAGE_SHIFT;
 
-	spin_lock_irqsave(&css_set_lock, flags);
 	if (nr_pages)
 		obj_cgroup_uncharge_pages(objcg, nr_pages);
+
+	spin_lock_irqsave(&css_set_lock, flags);
 	list_del(&objcg->list);
 	spin_unlock_irqrestore(&css_set_lock, flags);
 
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-memcontrol-fix-root_mem_cgroup-charging.patch
mm-memcontrol-fix-page-charging-in-page-replacement.patch
mm-memcontrol-bail-out-early-when-mm-in-get_mem_cgroup_from_mm.patch
mm-memcontrol-remove-the-pgdata-parameter-of-mem_cgroup_page_lruvec.patch
mm-memcontrol-simplify-lruvec_holds_page_lru_lock.patch
mm-memcontrol-rename-lruvec_holds_page_lru_lock-to-page_matches_lruvec.patch
mm-memcontrol-simplify-the-logic-of-objcg-pinning-memcg.patch
mm-memcontrol-move-obj_cgroup_uncharge_pages-out-of-css_set_lock.patch
mm-vmscan-remove-noinline_for_stack.patch
mm-memory_hotplug-factor-out-bootmem-core-functions-to-bootmem_infoc.patch
mm-hugetlb-introduce-a-new-config-hugetlb_page_free_vmemmap.patch
mm-hugetlb-gather-discrete-indexes-of-tail-page.patch
mm-hugetlb-free-the-vmemmap-pages-associated-with-each-hugetlb-page.patch
mm-hugetlb-defer-freeing-of-hugetlb-pages.patch
mm-hugetlb-alloc-the-vmemmap-pages-associated-with-each-hugetlb-page.patch
mm-hugetlb-add-a-kernel-parameter-hugetlb_free_vmemmap.patch
mm-memory_hotplug-disable-memmap_on_memory-when-hugetlb_free_vmemmap-enabled.patch
mm-hugetlb-introduce-nr_free_vmemmap_pages-in-the-struct-hstate.patch