[Devel] [PATCH RHEL7 COMMIT] ms/mm/list_lru.c: add memcg argument to list_lru_from_kmem()

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-862.11.6.vz7.71.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-862.11.6.vz7.71.8
------>
commit 2fe139e3bac52d16692b38e3b3ce681b985d5a87
Author: Kirill Tkhai <ktkhai at virtuozzo.com>
Date:   Wed Sep 5 12:37:11 2018 +0300

    ms/mm/list_lru.c: add memcg argument to list_lru_from_kmem()
    
    ms commit 44bd4a4759d5
    
    This is just refactoring to allow the next patches to have memcg pointer
    in list_lru_from_kmem().
    
    Link: http://lkml.kernel.org/r/153063060664.1818.9541345386733498582.stgit@localhost.localdomain
    Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
    
    Acked-by: Vladimir Davydov <vdavydov.dev at gmail.com>
    Tested-by: Shakeel Butt <shakeelb at google.com>
    Cc: Al Viro <viro at zeniv.linux.org.uk>
    Cc: Andrey Ryabinin <aryabinin at virtuozzo.com>
    Cc: Chris Wilson <chris at chris-wilson.co.uk>
    Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
    Cc: Guenter Roeck <linux at roeck-us.net>
    Cc: "Huang, Ying" <ying.huang at intel.com>
    Cc: Johannes Weiner <hannes at cmpxchg.org>
    Cc: Josef Bacik <jbacik at fb.com>
    Cc: Li RongQing <lirongqing at baidu.com>
    Cc: Matthew Wilcox <willy at infradead.org>
    Cc: Matthias Kaehlcke <mka at chromium.org>
    Cc: Mel Gorman <mgorman at techsingularity.net>
    Cc: Michal Hocko <mhocko at kernel.org>
    Cc: Minchan Kim <minchan at kernel.org>
    Cc: Philippe Ombredanne <pombredanne at nexb.com>
    Cc: Roman Gushchin <guro at fb.com>
    Cc: Sahitya Tummala <stummala at codeaurora.org>
    Cc: Stephen Rothwell <sfr at canb.auug.org.au>
    Cc: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
    Cc: Thomas Gleixner <tglx at linutronix.de>
    Cc: Waiman Long <longman at redhat.com>
    Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
    Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
    
    =====================
    Patchset description:
    
    Port "Improve shrink_slab() scalability" patchset
    
    https://jira.sw.ru/browse/PSBM-88027
    
    This is backport of the patchset improving the performance
    of overcommited containers with many memcgs and mounts.
    The original set is in Linus' tree, and came into 4.19-rc1.
    
    Kirill Tkhai (12):
          mm: assign id to every memcg-aware shrinker
          mm/memcontrol.c: move up for_each_mem_cgroup{, _tree} defines
          mm, memcg: assign memcg-aware shrinkers bitmap to memcg
          fs: propagate shrinker::id to list_lru
          mm/list_lru.c: add memcg argument to list_lru_from_kmem()
          mm/list_lru: pass dst_memcg argument to memcg_drain_list_lru_node()
          mm/list_lru.c: pass lru argument to memcg_drain_list_lru_node()
          mm/list_lru.c: set bit in memcg shrinker bitmap on first list_lru item appearance
          mm/memcontrol.c: export mem_cgroup_is_root()
          mm/vmscan.c: iterate only over charged shrinkers during memcg shrink_slab()
          mm: add SHRINK_EMPTY shrinker methods return value
          mm/vmscan.c: clear shrinker bit if there are no objects related to memcg
    
    Vladimir Davydov (1):
          mm/vmscan.c: generalize shrink_slab() calls in shrink_node()
---
 mm/list_lru.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/mm/list_lru.c b/mm/list_lru.c
index 514a862717c5..7cb1640b7151 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -65,21 +65,27 @@ list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
 }
 
 static inline struct list_lru_one *
-list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
+list_lru_from_kmem(struct list_lru_node *nlru, void *ptr,
+		   struct mem_cgroup **memcg_ptr)
 {
+	struct list_lru_one *l = &nlru->lru;
 	struct list_lru_memcg *memcg_lrus;
-	struct mem_cgroup *memcg;
+	struct mem_cgroup *memcg = NULL;
 
 	memcg_lrus = rcu_dereference_check(nlru->memcg_lrus,
 					   lockdep_is_held(&nlru->lock));
 	if (!memcg_lrus)
-		return &nlru->lru;
+		goto out;
 
 	memcg = mem_cgroup_from_kmem(ptr);
 	if (!memcg)
-		return &nlru->lru;
+		goto out;
 
-	return list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
+	l = list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
+out:
+	if (memcg_ptr)
+		*memcg_ptr = memcg;
+	return l;
 }
 #else
 static inline bool list_lru_memcg_aware(struct list_lru *lru)
@@ -94,8 +100,11 @@ list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
 }
 
 static inline struct list_lru_one *
-list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
+list_lru_from_kmem(struct list_lru_node *nlru, void *ptr,
+		   struct mem_cgroup **memcg_ptr)
 {
+	if (memcg_ptr)
+		*memcg_ptr = NULL;
 	return &nlru->lru;
 }
 #endif /* CONFIG_MEMCG_KMEM */
@@ -107,7 +116,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item)
 	struct list_lru_one *l;
 
 	spin_lock(&nlru->lock);
-	l = list_lru_from_kmem(nlru, item);
+	l = list_lru_from_kmem(nlru, item, NULL);
 	if (list_empty(item)) {
 		list_add_tail(item, &l->list);
 		l->nr_items++;
@@ -126,7 +135,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item)
 	struct list_lru_one *l;
 
 	spin_lock(&nlru->lock);
-	l = list_lru_from_kmem(nlru, item);
+	l = list_lru_from_kmem(nlru, item, NULL);
 	if (!list_empty(item)) {
 		list_del_init(item);
 		l->nr_items--;