[PATCH 07/11] xfs: expose sysfs knob to control inode inactivation delay

From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org
Cc: linux-xfs@vger.kernel.org
Subject: [PATCH 07/11] xfs: expose sysfs knob to control inode inactivation delay
Date: Wed, 10 Mar 2021 19:06:19 -0800	[thread overview]
Message-ID: <161543197945.1947934.7946093923141335693.stgit@magnolia> (raw)
In-Reply-To: <161543194009.1947934.9910987247994410125.stgit@magnolia>

From: Darrick J. Wong <djwong@kernel.org>

Allow administrators to control the length that we defer inode
inactivation.  By default we'll set the delay to 5 seconds, as an
arbitrary choice between allowing for some batching of a deltree
operation, and not letting too many inodes pile up in memory.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 Documentation/admin-guide/xfs.rst |    9 +++++++++
 fs/xfs/xfs_globals.c              |    3 +++
 fs/xfs/xfs_icache.c               |    2 +-
 fs/xfs/xfs_linux.h                |    1 +
 fs/xfs/xfs_sysctl.c               |    9 +++++++++
 fs/xfs/xfs_sysctl.h               |    1 +
 6 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst
index f9b109bfc6a6..608d0ba7a86e 100644
--- a/Documentation/admin-guide/xfs.rst
+++ b/Documentation/admin-guide/xfs.rst
@@ -277,6 +277,15 @@ The following sysctls are available for the XFS filesystem:
 	references and returns timed-out AGs back to the free stream
 	pool.
 
+  fs.xfs.inode_gc_delay
+	(Units: centiseconds   Min: 1  Default: 200  Max: 360000)
+	The amount of time to delay garbage collection of inodes that
+	have been closed or have been unlinked from the directory tree.
+	Garbage collection here means clearing speculative preallocations
+	from linked files and freeing unlinked inodes.  A higher value
+	here enables more batching at a cost of delayed reclamation of
+	incore inodes.
+
   fs.xfs.speculative_prealloc_lifetime
 	(Units: seconds   Min: 1  Default: 300  Max: 86400)
 	The interval at which the background scanning for inodes
diff --git a/fs/xfs/xfs_globals.c b/fs/xfs/xfs_globals.c
index f62fa652c2fd..2945c2c54cf0 100644
--- a/fs/xfs/xfs_globals.c
+++ b/fs/xfs/xfs_globals.c
@@ -28,6 +28,9 @@ xfs_param_t xfs_params = {
 	.rotorstep	= {	1,		1,		255	},
 	.inherit_nodfrg	= {	0,		1,		1	},
 	.fstrm_timer	= {	1,		30*100,		3600*100},
+	.inodegc_timer	= {	1,		2*100,		3600*100},
+
+	/* Values below here are measured in seconds */
 	.blockgc_timer	= {	1,		300,		3600*24},
 };
 
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 1b7652af5ee5..6081bba3c6ce 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -250,7 +250,7 @@ xfs_inodegc_queue(
 	rcu_read_lock();
 	if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_INACTIVE_TAG))
 		queue_delayed_work(mp->m_gc_workqueue, &mp->m_inodegc_work,
-				2 * HZ);
+				msecs_to_jiffies(xfs_inodegc_centisecs * 10));
 	rcu_read_unlock();
 }
 
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index af6be9b9ccdf..b4c5a2c71f43 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -99,6 +99,7 @@ typedef __u32			xfs_nlink_t;
 #define xfs_inherit_nodefrag	xfs_params.inherit_nodfrg.val
 #define xfs_fstrm_centisecs	xfs_params.fstrm_timer.val
 #define xfs_blockgc_secs	xfs_params.blockgc_timer.val
+#define xfs_inodegc_centisecs	xfs_params.inodegc_timer.val
 
 #define current_cpu()		(raw_smp_processor_id())
 #define current_set_flags_nested(sp, f)		\
diff --git a/fs/xfs/xfs_sysctl.c b/fs/xfs/xfs_sysctl.c
index 546a6cd96729..878f31d3a587 100644
--- a/fs/xfs/xfs_sysctl.c
+++ b/fs/xfs/xfs_sysctl.c
@@ -176,6 +176,15 @@ static struct ctl_table xfs_table[] = {
 		.extra1		= &xfs_params.fstrm_timer.min,
 		.extra2		= &xfs_params.fstrm_timer.max,
 	},
+	{
+		.procname	= "inode_gc_delay",
+		.data		= &xfs_params.inodegc_timer.val,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &xfs_params.inodegc_timer.min,
+		.extra2		= &xfs_params.inodegc_timer.max
+	},
 	{
 		.procname	= "speculative_prealloc_lifetime",
 		.data		= &xfs_params.blockgc_timer.val,
diff --git a/fs/xfs/xfs_sysctl.h b/fs/xfs/xfs_sysctl.h
index 7692e76ead33..a045c33c3d30 100644
--- a/fs/xfs/xfs_sysctl.h
+++ b/fs/xfs/xfs_sysctl.h
@@ -36,6 +36,7 @@ typedef struct xfs_param {
 	xfs_sysctl_val_t inherit_nodfrg;/* Inherit the "nodefrag" inode flag. */
 	xfs_sysctl_val_t fstrm_timer;	/* Filestream dir-AG assoc'n timeout. */
 	xfs_sysctl_val_t blockgc_timer;	/* Interval between blockgc scans */
+	xfs_sysctl_val_t inodegc_timer;	/* Inode inactivation scan interval */
 } xfs_param_t;
 
 /*

