All of lore.kernel.org
 help / color / mirror / Atom feed
From: Qi Zheng <zhengqi.arch@bytedance.com>
To: akpm@linux-foundation.org, hannes@cmpxchg.org,
	shakeelb@google.com, mhocko@kernel.org, roman.gushchin@linux.dev,
	muchun.song@linux.dev, david@redhat.com, shy828301@gmail.com
Cc: tkhai@ya.ru, sultan@kerneltoast.com, dave@stgolabs.net,
	penguin-kernel@I-love.SAKURA.ne.jp, paulmck@kernel.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Qi Zheng <zhengqi.arch@bytedance.com>
Subject: [PATCH 5/5] mm: shrinkers: convert shrinker_rwsem to mutex
Date: Mon, 20 Feb 2023 17:16:37 +0800	[thread overview]
Message-ID: <20230220091637.64865-6-zhengqi.arch@bytedance.com> (raw)
In-Reply-To: <20230220091637.64865-1-zhengqi.arch@bytedance.com>

Now there are no readers of shrinker_rwsem, so we
can simply replace it with mutex lock.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 drivers/md/dm-cache-metadata.c |  2 +-
 drivers/md/dm-thin-metadata.c  |  2 +-
 fs/super.c                     |  2 +-
 mm/shrinker_debug.c            | 14 +++++++-------
 mm/vmscan.c                    | 30 +++++++++++++++---------------
 5 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index acffed750e3e..9e0c69958587 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -1828,7 +1828,7 @@ int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
 	 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
 	 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
 	 * shrinker associated with the block manager's bufio client vs cmd root_lock).
-	 * - must take shrinker_rwsem without holding cmd->root_lock
+	 * - must take shrinker_mutex without holding cmd->root_lock
 	 */
 	new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 					 CACHE_MAX_CONCURRENT_LOCKS);
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index fd464fb024c3..9f5cb52c5763 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1887,7 +1887,7 @@ int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
 	 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
 	 * pmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
 	 * shrinker associated with the block manager's bufio client vs pmd root_lock).
-	 * - must take shrinker_rwsem without holding pmd->root_lock
+	 * - must take shrinker_mutex without holding pmd->root_lock
 	 */
 	new_bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 					 THIN_MAX_CONCURRENT_LOCKS);
diff --git a/fs/super.c b/fs/super.c
index 84332d5cb817..91a4037b1d95 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -54,7 +54,7 @@ static char *sb_writers_name[SB_FREEZE_LEVELS] = {
  * One thing we have to be careful of with a per-sb shrinker is that we don't
  * drop the last active reference to the superblock from within the shrinker.
  * If that happens we could trigger unregistering the shrinker from within the
- * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we
+ * shrinker path and that leads to deadlock on the shrinker_mutex. Hence we
  * take a passive reference to the superblock to avoid this from occurring.
  */
 static unsigned long super_cache_scan(struct shrinker *shrink,
diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c
index 6a26e8ac40aa..4c3a5d9afb5c 100644
--- a/mm/shrinker_debug.c
+++ b/mm/shrinker_debug.c
@@ -7,7 +7,7 @@
 #include <linux/memcontrol.h>
 
 /* defined in vmscan.c */
-extern struct rw_semaphore shrinker_rwsem;
+extern struct mutex shrinker_mutex;
 extern struct list_head shrinker_list;
 extern struct srcu_struct shrinker_srcu;
 
@@ -167,7 +167,7 @@ int shrinker_debugfs_add(struct shrinker *shrinker)
 	char buf[128];
 	int id;
 
-	lockdep_assert_held(&shrinker_rwsem);
+	lockdep_assert_held(&shrinker_mutex);
 
 	/* debugfs isn't initialized yet, add debugfs entries later. */
 	if (!shrinker_debugfs_root)
@@ -210,7 +210,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
 	if (!new)
 		return -ENOMEM;
 
-	down_write(&shrinker_rwsem);
+	mutex_lock(&shrinker_mutex);
 
 	old = shrinker->name;
 	shrinker->name = new;
@@ -228,7 +228,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
 			shrinker->debugfs_entry = entry;
 	}
 
-	up_write(&shrinker_rwsem);
+	mutex_unlock(&shrinker_mutex);
 
 	kfree_const(old);
 
@@ -240,7 +240,7 @@ struct dentry *shrinker_debugfs_remove(struct shrinker *shrinker)
 {
 	struct dentry *entry = shrinker->debugfs_entry;
 
-	lockdep_assert_held(&shrinker_rwsem);
+	lockdep_assert_held(&shrinker_mutex);
 
 	kfree_const(shrinker->name);
 	shrinker->name = NULL;
@@ -265,14 +265,14 @@ static int __init shrinker_debugfs_init(void)
 	shrinker_debugfs_root = dentry;
 
 	/* Create debugfs entries for shrinkers registered at boot */
-	down_write(&shrinker_rwsem);
+	mutex_lock(&shrinker_mutex);
 	list_for_each_entry(shrinker, &shrinker_list, list)
 		if (!shrinker->debugfs_entry) {
 			ret = shrinker_debugfs_add(shrinker);
 			if (ret)
 				break;
 		}
-	up_write(&shrinker_rwsem);
+	mutex_unlock(&shrinker_mutex);
 
 	return ret;
 }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b8da56beba96..f94bfe540675 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -35,7 +35,7 @@
 #include <linux/cpuset.h>
 #include <linux/compaction.h>
 #include <linux/notifier.h>
-#include <linux/rwsem.h>
+#include <linux/mutex.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
@@ -202,7 +202,7 @@ static void set_task_reclaim_state(struct task_struct *task,
 }
 
 LIST_HEAD(shrinker_list);
-DECLARE_RWSEM(shrinker_rwsem);
+DEFINE_MUTEX(shrinker_mutex);
 DEFINE_SRCU(shrinker_srcu);
 
 #ifdef CONFIG_MEMCG
@@ -224,7 +224,7 @@ static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
 {
 	return srcu_dereference_check(memcg->nodeinfo[nid]->shrinker_info,
 				      &shrinker_srcu,
-				      lockdep_is_held(&shrinker_rwsem));
+				      lockdep_is_held(&shrinker_mutex));
 }
 
 static struct shrinker_info *shrinker_info_srcu(struct mem_cgroup *memcg,
@@ -297,7 +297,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
 	int nid, size, ret = 0;
 	int map_size, defer_size = 0;
 
-	down_write(&shrinker_rwsem);
+	mutex_lock(&shrinker_mutex);
 	map_size = shrinker_map_size(shrinker_nr_max);
 	defer_size = shrinker_defer_size(shrinker_nr_max);
 	size = map_size + defer_size;
@@ -312,7 +312,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
 		info->map = (void *)info->nr_deferred + defer_size;
 		rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info);
 	}
-	up_write(&shrinker_rwsem);
+	mutex_unlock(&shrinker_mutex);
 
 	return ret;
 }
@@ -337,7 +337,7 @@ static int expand_shrinker_info(int new_id)
 	if (!root_mem_cgroup)
 		goto out;
 
-	lockdep_assert_held(&shrinker_rwsem);
+	lockdep_assert_held(&shrinker_mutex);
 
 	map_size = shrinker_map_size(new_nr_max);
 	defer_size = shrinker_defer_size(new_nr_max);
@@ -384,7 +384,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 	if (mem_cgroup_disabled())
 		return -ENOSYS;
 
-	down_write(&shrinker_rwsem);
+	mutex_lock(&shrinker_mutex);
 	id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL);
 	if (id < 0)
 		goto unlock;
@@ -398,7 +398,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 	shrinker->id = id;
 	ret = 0;
 unlock:
-	up_write(&shrinker_rwsem);
+	mutex_unlock(&shrinker_mutex);
 	return ret;
 }
 
@@ -408,7 +408,7 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker)
 
 	BUG_ON(id < 0);
 
-	lockdep_assert_held(&shrinker_rwsem);
+	lockdep_assert_held(&shrinker_mutex);
 
 	idr_remove(&shrinker_idr, id);
 }
@@ -701,9 +701,9 @@ void free_prealloced_shrinker(struct shrinker *shrinker)
 	shrinker->name = NULL;
 #endif
 	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
-		down_write(&shrinker_rwsem);
+		mutex_lock(&shrinker_mutex);
 		unregister_memcg_shrinker(shrinker);
-		up_write(&shrinker_rwsem);
+		mutex_unlock(&shrinker_mutex);
 		return;
 	}
 
@@ -713,11 +713,11 @@ void free_prealloced_shrinker(struct shrinker *shrinker)
 
 void register_shrinker_prepared(struct shrinker *shrinker)
 {
-	down_write(&shrinker_rwsem);
+	mutex_lock(&shrinker_mutex);
 	list_add_tail_rcu(&shrinker->list, &shrinker_list);
 	shrinker->flags |= SHRINKER_REGISTERED;
 	shrinker_debugfs_add(shrinker);
-	up_write(&shrinker_rwsem);
+	mutex_unlock(&shrinker_mutex);
 }
 
 static int __register_shrinker(struct shrinker *shrinker)
@@ -767,13 +767,13 @@ void unregister_shrinker(struct shrinker *shrinker)
 	if (!(shrinker->flags & SHRINKER_REGISTERED))
 		return;
 
-	down_write(&shrinker_rwsem);
+	mutex_lock(&shrinker_mutex);
 	list_del_rcu(&shrinker->list);
 	shrinker->flags &= ~SHRINKER_REGISTERED;
 	if (shrinker->flags & SHRINKER_MEMCG_AWARE)
 		unregister_memcg_shrinker(shrinker);
 	debugfs_entry = shrinker_debugfs_remove(shrinker);
-	up_write(&shrinker_rwsem);
+	mutex_unlock(&shrinker_mutex);
 
 	synchronize_srcu(&shrinker_srcu);
 
-- 
2.20.1


      parent reply	other threads:[~2023-02-20  9:17 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-20  9:16 [PATCH 0/5] make slab shrink lockless Qi Zheng
2023-02-20  9:16 ` [PATCH 1/5] mm: vmscan: make global " Qi Zheng
2023-02-20  9:16 ` [PATCH 2/5] mm: vmscan: make memcg " Qi Zheng
2023-02-21 21:28   ` Kirill Tkhai
2023-02-22  7:32     ` Qi Zheng
2023-02-22 19:58       ` Kirill Tkhai
2023-02-23  4:36         ` Qi Zheng
2023-02-21 21:43   ` Kirill Tkhai
2023-02-22  8:16     ` Qi Zheng
2023-02-22  8:21       ` Qi Zheng
2023-02-22 20:05         ` Kirill Tkhai
2023-02-23  4:37           ` Qi Zheng
2023-02-20  9:16 ` [PATCH 3/5] mm: shrinkers: make count and scan in shrinker debugfs lockless Qi Zheng
2023-02-20 13:22   ` kernel test robot
2023-02-20  9:16 ` [PATCH 4/5] mm: vmscan: remove shrinker_rwsem from synchronize_shrinkers() Qi Zheng
2023-02-20  9:16 ` Qi Zheng [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230220091637.64865-6-zhengqi.arch@bytedance.com \
    --to=zhengqi.arch@bytedance.com \
    --cc=akpm@linux-foundation.org \
    --cc=dave@stgolabs.net \
    --cc=david@redhat.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=muchun.song@linux.dev \
    --cc=paulmck@kernel.org \
    --cc=penguin-kernel@I-love.SAKURA.ne.jp \
    --cc=roman.gushchin@linux.dev \
    --cc=shakeelb@google.com \
    --cc=shy828301@gmail.com \
    --cc=sultan@kerneltoast.com \
    --cc=tkhai@ya.ru \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.