From: Yang Shi <shy828301@gmail.com>
To: guro@fb.com, ktkhai@virtuozzo.com, shakeelb@google.com,
david@fromorbit.com, hannes@cmpxchg.org, mhocko@suse.com,
akpm@linux-foundation.org
Cc: shy828301@gmail.com, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 4/9] mm: vmscan: use a new flag to indicate shrinker is registered
Date: Wed, 2 Dec 2020 10:27:20 -0800 [thread overview]
Message-ID: <20201202182725.265020-5-shy828301@gmail.com> (raw)
In-Reply-To: <20201202182725.265020-1-shy828301@gmail.com>
Currently registered shrinker is indicated by non-NULL shrinker->nr_deferred.
This approach is fine with nr_deferred atthe shrinker level, but the following
patches will move MEMCG_AWARE shrinkers' nr_deferred to memcg level, so their
shrinker->nr_deferred would always be NULL. This would prevent the shrinkers
from unregistering correctly.
Introduce a new "state" field to indicate if shrinker is registered or not.
We could use the highest bit of flags, but it may be a little bit complicated to
extract that bit and the flags is accessed frequently by vmscan (every time shrinker
is called). So add a new field in "struct shrinker", we may waster a little bit
memory, but it should be very few since there should be not too many registered
shrinkers on a normal system.
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
include/linux/shrinker.h | 4 ++++
mm/vmscan.c | 13 +++++++++----
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index 0f80123650e2..0bb5be88e41d 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -35,6 +35,9 @@ struct shrink_control {
#define SHRINK_STOP (~0UL)
#define SHRINK_EMPTY (~0UL - 1)
+
+#define SHRINKER_REGISTERED 0x1
+
/*
* A callback you can register to apply pressure to ageable caches.
*
@@ -66,6 +69,7 @@ struct shrinker {
long batch; /* reclaim batch size, 0 = default */
int seeks; /* seeks to recreate an obj */
unsigned flags;
+ unsigned state;
/* These are for internal use */
struct list_head list;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 457ce04eebf2..0d628299e55c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -378,6 +378,7 @@ void register_shrinker_prepared(struct shrinker *shrinker)
if (shrinker->flags & SHRINKER_MEMCG_AWARE)
idr_replace(&shrinker_idr, shrinker, shrinker->id);
#endif
+ shrinker->state |= SHRINKER_REGISTERED;
up_write(&shrinker_rwsem);
}
@@ -397,13 +398,17 @@ EXPORT_SYMBOL(register_shrinker);
*/
void unregister_shrinker(struct shrinker *shrinker)
{
- if (!shrinker->nr_deferred)
- return;
- if (shrinker->flags & SHRINKER_MEMCG_AWARE)
- unregister_memcg_shrinker(shrinker);
down_write(&shrinker_rwsem);
+ if (!shrinker->state) {
+ up_write(&shrinker_rwsem);
+ return;
+ }
list_del(&shrinker->list);
+ shrinker->state &= ~SHRINKER_REGISTERED;
up_write(&shrinker_rwsem);
+
+ if (shrinker->flags & SHRINKER_MEMCG_AWARE)
+ unregister_memcg_shrinker(shrinker);
kfree(shrinker->nr_deferred);
shrinker->nr_deferred = NULL;
}
--
2.26.2
next prev parent reply other threads:[~2020-12-02 18:28 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 18:27 [RFC PATCH 0/9] Make shrinker's nr_deferred memcg aware Yang Shi
2020-12-02 18:27 ` [PATCH 1/9] mm: vmscan: simplify nr_deferred update code Yang Shi
2020-12-03 2:56 ` Roman Gushchin
2020-12-02 18:27 ` [PATCH 2/9] mm: vmscan: use nid from shrink_control for tracepoint Yang Shi
2020-12-03 3:13 ` Xiaqing (A)
2020-12-11 19:20 ` Yang Shi
2020-12-02 18:27 ` [PATCH 3/9] mm: memcontrol: rename memcg_shrinker_map_mutex to memcg_shrinker_mutex Yang Shi
2020-12-02 18:27 ` Yang Shi [this message]
2020-12-03 3:01 ` [PATCH 4/9] mm: vmscan: use a new flag to indicate shrinker is registered Roman Gushchin
2020-12-03 4:59 ` Yang Shi
2020-12-03 20:08 ` Roman Gushchin
2020-12-03 22:25 ` Yang Shi
2020-12-04 18:52 ` Johannes Weiner
2020-12-04 21:24 ` Yang Shi
2020-12-02 18:27 ` [PATCH 5/9] mm: memcontrol: add per memcg shrinker nr_deferred Yang Shi
2020-12-03 3:06 ` Roman Gushchin
2020-12-03 4:54 ` Yang Shi
2020-12-03 18:03 ` Yang Shi
2020-12-03 20:07 ` Roman Gushchin
2020-12-03 22:49 ` Yang Shi
2020-12-03 23:30 ` Roman Gushchin
2020-12-04 0:22 ` Yang Shi
2020-12-10 15:33 ` Johannes Weiner
2020-12-10 19:12 ` Yang Shi
2020-12-11 17:52 ` Yang Shi
2020-12-10 21:59 ` Yang Shi
2020-12-02 18:27 ` [PATCH 6/9] mm: vmscan: use per memcg nr_deferred of shrinker Yang Shi
2020-12-03 3:08 ` Roman Gushchin
2020-12-03 5:01 ` Yang Shi
2020-12-03 11:40 ` Kirill Tkhai
2020-12-08 17:13 ` Yang Shi
2020-12-09 15:41 ` Kirill Tkhai
2020-12-09 17:32 ` Yang Shi
2020-12-10 15:13 ` Johannes Weiner
2020-12-10 15:17 ` Kirill Tkhai
2020-12-15 16:44 ` Johannes Weiner
2020-12-02 18:27 ` [PATCH 7/9] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers Yang Shi
2020-12-02 18:27 ` [PATCH 8/9] mm: memcontrol: reparent nr_deferred when memcg offline Yang Shi
2020-12-02 18:27 ` [PATCH 9/9] mm: vmscan: shrink deferred objects proportional to priority Yang Shi
2020-12-03 2:52 ` [RFC PATCH 0/9] Make shrinker's nr_deferred memcg aware Roman Gushchin
2020-12-03 17:52 ` Yang Shi
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