+ mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm: vmscan: use per memcg nr_deferred of shrinker
has been added to the -mm tree.  Its filename is
     mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch

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------------------------------------------------------
From: Yang Shi <shy828301@gmail.com>
Subject: mm: vmscan: use per memcg nr_deferred of shrinker

Use per memcg's nr_deferred for memcg aware shrinkers.  The shrinker's
nr_deferred will be used in the following cases:

    1. Non memcg aware shrinkers
    2. !CONFIG_MEMCG
    3. memcg is disabled by boot parameter

Link: https://lkml.kernel.org/r/20210311190845.9708-11-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmscan.c |   78 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 66 insertions(+), 12 deletions(-)

--- a/mm/vmscan.c~mm-vmscan-use-per-memcg-nr_deferred-of-shrinker
+++ a/mm/vmscan.c
@@ -376,6 +376,24 @@ static void unregister_memcg_shrinker(st
 	idr_remove(&shrinker_idr, id);
 }
 
+static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
+				   struct mem_cgroup *memcg)
+{
+	struct shrinker_info *info;
+
+	info = shrinker_info_protected(memcg, nid);
+	return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0);
+}
+
+static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
+				  struct mem_cgroup *memcg)
+{
+	struct shrinker_info *info;
+
+	info = shrinker_info_protected(memcg, nid);
+	return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
+}
+
 static bool cgroup_reclaim(struct scan_control *sc)
 {
 	return sc->target_mem_cgroup;
@@ -414,6 +432,18 @@ static void unregister_memcg_shrinker(st
 {
 }
 
+static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
+				   struct mem_cgroup *memcg)
+{
+	return 0;
+}
+
+static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
+				  struct mem_cgroup *memcg)
+{
+	return 0;
+}
+
 static bool cgroup_reclaim(struct scan_control *sc)
 {
 	return false;
@@ -425,6 +455,39 @@ static bool writeback_throttling_sane(st
 }
 #endif
 
+static long xchg_nr_deferred(struct shrinker *shrinker,
+			     struct shrink_control *sc)
+{
+	int nid = sc->nid;
+
+	if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
+		nid = 0;
+
+	if (sc->memcg &&
+	    (shrinker->flags & SHRINKER_MEMCG_AWARE))
+		return xchg_nr_deferred_memcg(nid, shrinker,
+					      sc->memcg);
+
+	return atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
+}
+
+
+static long add_nr_deferred(long nr, struct shrinker *shrinker,
+			    struct shrink_control *sc)
+{
+	int nid = sc->nid;
+
+	if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
+		nid = 0;
+
+	if (sc->memcg &&
+	    (shrinker->flags & SHRINKER_MEMCG_AWARE))
+		return add_nr_deferred_memcg(nr, nid, shrinker,
+					     sc->memcg);
+
+	return atomic_long_add_return(nr, &shrinker->nr_deferred[nid]);
+}
+
 /*
  * This misses isolated pages which are not accounted for to save counters.
  * As the data only determines if reclaim or compaction continues, it is
@@ -561,14 +624,10 @@ static unsigned long do_shrink_slab(stru
 	long freeable;
 	long nr;
 	long new_nr;
-	int nid = shrinkctl->nid;
 	long batch_size = shrinker->batch ? shrinker->batch
 					  : SHRINK_BATCH;
 	long scanned = 0, next_deferred;
 
-	if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
-		nid = 0;
-
 	freeable = shrinker->count_objects(shrinker, shrinkctl);
 	if (freeable == 0 || freeable == SHRINK_EMPTY)
 		return freeable;
@@ -578,7 +637,7 @@ static unsigned long do_shrink_slab(stru
 	 * and zero it so that other concurrent shrinker invocations
 	 * don't also do this scanning work.
 	 */
-	nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
+	nr = xchg_nr_deferred(shrinker, shrinkctl);
 
 	total_scan = nr;
 	if (shrinker->seeks) {
@@ -669,14 +728,9 @@ static unsigned long do_shrink_slab(stru
 		next_deferred = 0;
 	/*
 	 * move the unused scan count back into the shrinker in a
-	 * manner that handles concurrent updates. If we exhausted the
-	 * scan, there is no need to do an update.
+	 * manner that handles concurrent updates.
 	 */
-	if (next_deferred > 0)
-		new_nr = atomic_long_add_return(next_deferred,
-						&shrinker->nr_deferred[nid]);
-	else
-		new_nr = atomic_long_read(&shrinker->nr_deferred[nid]);
+	new_nr = add_nr_deferred(next_deferred, shrinker, shrinkctl);
 
 	trace_mm_shrink_slab_end(shrinker, shrinkctl->nid, freed, nr, new_nr, total_scan);
 	return freed;
_

Patches currently in -mm which might be from shy828301@gmail.com are

mm-vmscan-use-nid-from-shrink_control-for-tracepoint.patch
mm-vmscan-consolidate-shrinker_maps-handling-code.patch
mm-vmscan-use-shrinker_rwsem-to-protect-shrinker_maps-allocation.patch
mm-vmscan-remove-memcg_shrinker_map_size.patch
mm-vmscan-use-kvfree_rcu-instead-of-call_rcu.patch
mm-memcontrol-rename-shrinker_map-to-shrinker_info.patch
mm-vmscan-add-shrinker_info_protected-helper.patch
mm-vmscan-use-a-new-flag-to-indicate-shrinker-is-registered.patch
mm-vmscan-add-per-memcg-shrinker-nr_deferred.patch
mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch
mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers.patch
mm-memcontrol-reparent-nr_deferred-when-memcg-offline.patch
mm-vmscan-shrink-deferred-objects-proportional-to-priority.patch