+ mm-memcontrol-make-the-slab-calculation-consistent.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm/memcontrol: make the slab calculation consistent
has been added to the -mm tree.  Its filename is
     mm-memcontrol-make-the-slab-calculation-consistent.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-make-the-slab-calculation-consistent.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-make-the-slab-calculation-consistent.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/memcontrol: make the slab calculation consistent

Although the ratio of the slab is one, we also should read the ratio from
the related memory_stats instead of hard-coding.  And the local variable
of size is already the value of slab_unreclaimable.  So we do not need to
read again.  Simplify the code here.

Link: https://lkml.kernel.org/r/20201203031111.3187-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |   26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

--- a/mm/memcontrol.c~mm-memcontrol-make-the-slab-calculation-consistent
+++ a/mm/memcontrol.c
@@ -1612,12 +1612,22 @@ static int __init memory_stats_init(void
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
+		switch (memory_stats[i].idx) {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-		if (memory_stats[i].idx == NR_ANON_THPS ||
-		    memory_stats[i].idx == NR_FILE_THPS ||
-		    memory_stats[i].idx == NR_SHMEM_THPS)
+		case NR_ANON_THPS:
+		case NR_FILE_THPS:
+		case NR_SHMEM_THPS:
 			memory_stats[i].ratio = HPAGE_PMD_SIZE;
+			break;
 #endif
+		case NR_SLAB_UNRECLAIMABLE_B:
+			VM_BUG_ON(i < 1);
+			VM_BUG_ON(memory_stats[i - 1].idx != NR_SLAB_RECLAIMABLE_B);
+			break;
+		default:
+			break;
+		}
+
 		VM_BUG_ON(!memory_stats[i].ratio);
 		VM_BUG_ON(memory_stats[i].idx >= MEMCG_NR_STAT);
 	}
@@ -1653,9 +1663,15 @@ static char *memory_stat_format(struct m
 		size *= memory_stats[i].ratio;
 		seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size);
 
+		/*
+		 * We are printing reclaimable, unreclaimable of the slab
+		 * and the sum of both.
+		 */
 		if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) {
-			size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
-			       memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B);
+			int idx = i - 1;
+
+			size += memcg_page_state(memcg, memory_stats[idx].idx) *
+				memory_stats[idx].ratio;
 			seq_buf_printf(&s, "slab %llu\n", size);
 		}
 	}
_

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

mm-memcontrol-remove-unused-mod_memcg_obj_state.patch
mm-memcg-slab-fix-return-child-memcg-objcg-for-root-memcg.patch
mm-memcg-slab-fix-use-after-free-in-obj_cgroup_charge.patch
mm-memcg-slab-rename-_lruvec_slab_state-to-_lruvec_kmem_state.patch
mm-memcontrol-make-the-slab-calculation-consistent.patch
mm-page_isolation-do-not-isolate-the-max-order-page.patch