Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Qi Zheng <zhengqi.arch@bytedance.com>
To:     akpm@linux-foundation.org, david@fromorbit.com, tkhai@ya.ru,
        vbabka@suse.cz, roman.gushchin@linux.dev, djwong@kernel.org,
        brauner@kernel.org, paulmck@kernel.org, tytso@mit.edu
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-arm-msm@vger.kernel.org, dm-devel@redhat.com,
        linux-raid@vger.kernel.org, linux-bcache@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org,
        linux-btrfs@vger.kernel.org, Qi Zheng <zhengqi.arch@bytedance.com>
Subject: [PATCH 18/29] xfs: dynamically allocate the xfs-inodegc shrinker
Date:   Thu, 22 Jun 2023 16:53:24 +0800
Message-Id: <20230622085335.77010-19-zhengqi.arch@bytedance.com>
In-Reply-To: <20230622085335.77010-1-zhengqi.arch@bytedance.com>
References: <20230622085335.77010-1-zhengqi.arch@bytedance.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In preparation for implementing lockless slab shrink,
we need to dynamically allocate the xfs-inodegc shrinker,
so that it can be freed asynchronously using kfree_rcu().
Then it doesn't need to wait for RCU read-side critical
section when releasing the struct xfs_mount.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 fs/xfs/xfs_icache.c | 27 ++++++++++++++++-----------
 fs/xfs/xfs_mount.c  |  4 ++--
 fs/xfs/xfs_mount.h  |  2 +-
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 453890942d9f..1ef0c9fa57de 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -2225,8 +2225,7 @@ xfs_inodegc_shrinker_count(
 	struct shrinker		*shrink,
 	struct shrink_control	*sc)
 {
-	struct xfs_mount	*mp = container_of(shrink, struct xfs_mount,
-						   m_inodegc_shrinker);
+	struct xfs_mount	*mp = shrink->private_data;
 	struct xfs_inodegc	*gc;
 	int			cpu;
 
@@ -2247,8 +2246,7 @@ xfs_inodegc_shrinker_scan(
 	struct shrinker		*shrink,
 	struct shrink_control	*sc)
 {
-	struct xfs_mount	*mp = container_of(shrink, struct xfs_mount,
-						   m_inodegc_shrinker);
+	struct xfs_mount	*mp = shrink->private_data;
 	struct xfs_inodegc	*gc;
 	int			cpu;
 	bool			no_items = true;
@@ -2284,13 +2282,20 @@ int
 xfs_inodegc_register_shrinker(
 	struct xfs_mount	*mp)
 {
-	struct shrinker		*shrink = &mp->m_inodegc_shrinker;
+	int ret;
 
-	shrink->count_objects = xfs_inodegc_shrinker_count;
-	shrink->scan_objects = xfs_inodegc_shrinker_scan;
-	shrink->seeks = 0;
-	shrink->flags = SHRINKER_NONSLAB;
-	shrink->batch = XFS_INODEGC_SHRINKER_BATCH;
+	mp->m_inodegc_shrinker =
+		shrinker_alloc_and_init(xfs_inodegc_shrinker_count,
+					xfs_inodegc_shrinker_scan,
+					XFS_INODEGC_SHRINKER_BATCH,
+					0, SHRINKER_NONSLAB, mp);
+	if (!mp->m_inodegc_shrinker)
+		return -ENOMEM;
+
+	ret = register_shrinker(mp->m_inodegc_shrinker, "xfs-inodegc:%s",
+				mp->m_super->s_id);
+	if (ret)
+		shrinker_free(mp->m_inodegc_shrinker);
 
-	return register_shrinker(shrink, "xfs-inodegc:%s", mp->m_super->s_id);
+	return ret;
 }
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index fb87ffb48f7f..67286859ad34 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1018,7 +1018,7 @@ xfs_mountfs(
  out_log_dealloc:
 	xfs_log_mount_cancel(mp);
  out_inodegc_shrinker:
-	unregister_shrinker(&mp->m_inodegc_shrinker);
+	unregister_and_free_shrinker(mp->m_inodegc_shrinker);
  out_fail_wait:
 	if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
 		xfs_buftarg_drain(mp->m_logdev_targp);
@@ -1100,7 +1100,7 @@ xfs_unmountfs(
 #if defined(DEBUG)
 	xfs_errortag_clearall(mp);
 #endif
-	unregister_shrinker(&mp->m_inodegc_shrinker);
+	unregister_and_free_shrinker(mp->m_inodegc_shrinker);
 	xfs_free_perag(mp);
 
 	xfs_errortag_del(mp);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e2866e7fa60c..562c294ca08e 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -217,7 +217,7 @@ typedef struct xfs_mount {
 	atomic_t		m_agirotor;	/* last ag dir inode alloced */
 
 	/* Memory shrinker to throttle and reprioritize inodegc */
-	struct shrinker		m_inodegc_shrinker;
+	struct shrinker		*m_inodegc_shrinker;
 	/*
 	 * Workqueue item so that we can coalesce multiple inode flush attempts
 	 * into a single flush.
-- 
2.30.2