+ slub-fix-unreclaimable-slab-stat-for-bulk-free.patch added to -mm tree

+ slub-fix-unreclaimable-slab-stat-for-bulk-free.patch added to -mm tree

[akpm]

The patch titled
     Subject: slub: fix unreclaimable slab stat for bulk free
has been added to the -mm tree.  Its filename is
     slub-fix-unreclaimable-slab-stat-for-bulk-free.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/slub-fix-unreclaimable-slab-stat-for-bulk-free.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/slub-fix-unreclaimable-slab-stat-for-bulk-free.patch

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------------------------------------------------------
From: Shakeel Butt <shakeelb@google.com>
Subject: slub: fix unreclaimable slab stat for bulk free

SLUB uses page allocator for higher order allocations and update
unreclaimable slab stat for such allocations.  At the moment, the bulk
free for SLUB does not share code with normal free code path for these
type of allocations and have missed the stat update.  So, fix the stat
update by common code.  The user visible impact of the bug is the
potential of inconsistent unreclaimable slab stat visible through meminfo
and vmstat.

Link: https://lkml.kernel.org/r/20210728155354.3440560-1-shakeelb@google.com
Fixes: 6a486c0ad4dc ("mm, sl[ou]b: improve memory accounting")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/slub.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

--- a/mm/slub.c~slub-fix-unreclaimable-slab-stat-for-bulk-free
+++ a/mm/slub.c
@@ -3236,6 +3236,16 @@ struct detached_freelist {
 	struct kmem_cache *s;
 };
 
+static inline void free_nonslab_page(struct page *page)
+{
+	unsigned int order = compound_order(page);
+
+	VM_BUG_ON_PAGE(!PageCompound(page), page);
+	kfree_hook(page_address(page));
+	mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order));
+	__free_pages(page, order);
+}
+
 /*
  * This function progressively scans the array with free objects (with
  * a limited look ahead) and extract objects belonging to the same
@@ -3272,9 +3282,7 @@ int build_detached_freelist(struct kmem_
 	if (!s) {
 		/* Handle kalloc'ed objects */
 		if (unlikely(!PageSlab(page))) {
-			BUG_ON(!PageCompound(page));
-			kfree_hook(object);
-			__free_pages(page, compound_order(page));
+			free_nonslab_page(page);
 			p[size] = NULL; /* mark object processed */
 			return size;
 		}
@@ -4250,13 +4258,7 @@ void kfree(const void *x)
 
 	page = virt_to_head_page(x);
 	if (unlikely(!PageSlab(page))) {
-		unsigned int order = compound_order(page);
-
-		BUG_ON(!PageCompound(page));
-		kfree_hook(object);
-		mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
-				      -(PAGE_SIZE << order));
-		__free_pages(page, order);
+		free_nonslab_page(page);
 		return;
 	}
 	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
_

Patches currently in -mm which might be from shakeelb@google.com are

slub-fix-unreclaimable-slab-stat-for-bulk-free.patch
writeback-memcg-simplify-cgroup_writeback_by_id.patch
memcg-switch-lruvec-stats-to-rstat.patch
memcg-infrastructure-to-flush-memcg-stats.patch
memcg-infrastructure-to-flush-memcg-stats-v5.patch