From: Waiman Long <longman@redhat.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Jonathan Corbet <corbet@lwn.net>,
Luis Chamberlain <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
Iurii Zaikin <yzaikin@google.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-doc@vger.kernel.org,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Eric Biggers <ebiggers@google.com>,
Dave Chinner <david@fromorbit.com>,
Eric Sandeen <sandeen@redhat.com>,
Waiman Long <longman@redhat.com>
Subject: [PATCH 07/11] fs/dcache: Add static key negative_reclaim_enable
Date: Wed, 26 Feb 2020 11:14:00 -0500 [thread overview]
Message-ID: <20200226161404.14136-8-longman@redhat.com> (raw)
In-Reply-To: <20200226161404.14136-1-longman@redhat.com>
Add a static_key negative_reclaim_enable to optimize the default case
where negative dentry directory limit "dentry-dir-max" is not set.
Signed-off-by: Waiman Long <longman@redhat.com>
---
fs/dcache.c | 30 ++++++++++++++++++++++++++++--
kernel/sysctl.c | 3 ++-
2 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index c5364c2ed5d8..149c0a6c1a6e 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -32,6 +32,7 @@
#include <linux/bit_spinlock.h>
#include <linux/rculist_bl.h>
#include <linux/list_lru.h>
+#include <linux/jump_label.h>
#include "internal.h"
#include "mount.h"
@@ -134,11 +135,13 @@ int dcache_dentry_dir_max_sysctl __read_mostly;
EXPORT_SYMBOL_GPL(dcache_dentry_dir_max_sysctl);
static LLIST_HEAD(negative_reclaim_list);
+static DEFINE_STATIC_KEY_FALSE(negative_reclaim_enable);
static void negative_reclaim_check(struct dentry *parent);
static void negative_reclaim_workfn(struct work_struct *work);
static DECLARE_WORK(negative_reclaim_work, negative_reclaim_workfn);
#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+proc_handler proc_dcache_dentry_dir_max;
/*
* Here we resort to our own counters instead of using generic per-cpu counters
@@ -188,6 +191,27 @@ int proc_nr_dentry(struct ctl_table *table, int write, void __user *buffer,
dentry_stat.nr_negative = get_nr_dentry_negative();
return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
}
+
+/*
+ * Sysctl proc handler for dcache_dentry_dir_max_sysctl
+ */
+int proc_dcache_dentry_dir_max(struct ctl_table *ctl, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int old = dcache_dentry_dir_max_sysctl;
+ int ret;
+
+ ret = proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
+
+ if (!write || ret || (dcache_dentry_dir_max_sysctl == old))
+ return ret;
+
+ if (!old && dcache_dentry_dir_max_sysctl)
+ static_branch_enable(&negative_reclaim_enable);
+ else if (old && !dcache_dentry_dir_max_sysctl)
+ static_branch_disable(&negative_reclaim_enable);
+ return 0;
+}
#endif
/*
@@ -876,7 +900,8 @@ void dput(struct dentry *dentry)
if (likely(retain_dentry(dentry))) {
struct dentry *neg_parent = NULL;
- if (d_is_negative(dentry)) {
+ if (static_branch_unlikely(&negative_reclaim_enable) &&
+ d_is_negative(dentry)) {
neg_parent = dentry->d_parent;
rcu_read_lock();
}
@@ -886,7 +911,8 @@ void dput(struct dentry *dentry)
* Negative dentry reclaim check is only done when
* a negative dentry is being put into a LRU list.
*/
- if (neg_parent)
+ if (static_branch_unlikely(&negative_reclaim_enable) &&
+ neg_parent)
negative_reclaim_check(neg_parent);
return;
}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index cd0a83ff1029..9a4b0a1376e8 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -119,6 +119,7 @@ extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
extern int sysctl_nr_trim_pages;
#endif
extern int dcache_dentry_dir_max_sysctl;
+extern proc_handler proc_dcache_dentry_dir_max;
/* Constants used for minimum and maximum */
#ifdef CONFIG_LOCKUP_DETECTOR
@@ -1956,7 +1957,7 @@ static struct ctl_table fs_table[] = {
.data = &dcache_dentry_dir_max_sysctl,
.maxlen = sizeof(dcache_dentry_dir_max_sysctl),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dcache_dentry_dir_max,
.extra1 = &zero,
},
{ }
--
2.18.1
next prev parent reply other threads:[~2020-02-26 16:15 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 16:13 [PATCH 00/11] fs/dcache: Limit # of negative dentries Waiman Long
2020-02-26 16:13 ` [PATCH 01/11] fs/dcache: Fix incorrect accounting " Waiman Long
2020-02-26 16:13 ` [PATCH 02/11] fs/dcache: Simplify __dentry_kill() Waiman Long
2020-02-26 16:13 ` [PATCH 03/11] fs/dcache: Add a counter to track number of children Waiman Long
2020-02-26 16:13 ` [PATCH 04/11] fs/dcache: Add sysctl parameter dentry-dir-max Waiman Long
2020-02-26 16:13 ` [PATCH 05/11] fs/dcache: Reclaim excessive negative dentries in directories Waiman Long
2020-02-26 16:13 ` [PATCH 06/11] fs/dcache: directory opportunistically stores # of positive dentries Waiman Long
2020-02-26 16:14 ` Waiman Long [this message]
2020-02-26 16:14 ` [PATCH 08/11] fs/dcache: Limit dentry reclaim count in negative_reclaim_workfn() Waiman Long
2020-02-26 16:14 ` [PATCH 09/11] fs/dcache: Don't allow small values for dentry-dir-max Waiman Long
2020-02-26 16:14 ` [PATCH 10/11] fs/dcache: Kill off dentry as last resort Waiman Long
2020-02-26 16:14 ` [PATCH 11/11] fs/dcache: Track # of negative dentries reclaimed & killed Waiman Long
2020-02-26 16:29 ` [PATCH 00/11] fs/dcache: Limit # of negative dentries Matthew Wilcox
2020-02-26 19:19 ` Waiman Long
2020-02-26 21:28 ` Matthew Wilcox
2020-02-26 21:28 ` Andreas Dilger
2020-02-26 21:45 ` Matthew Wilcox
2020-02-27 8:07 ` Dave Chinner
2020-02-27 9:55 ` Ian Kent
2020-02-28 3:34 ` Matthew Wilcox
2020-02-28 4:16 ` Ian Kent
2020-02-28 4:36 ` Ian Kent
2020-02-28 4:52 ` Al Viro
2020-02-28 4:22 ` Al Viro
2020-02-28 4:52 ` Ian Kent
2020-02-28 15:32 ` Waiman Long
2020-02-28 15:39 ` Matthew Wilcox
2020-02-28 19:32 ` Theodore Y. Ts'o
2020-02-27 19:04 ` Eric Sandeen
2020-02-27 22:39 ` Dave Chinner
2020-02-27 8:30 ` Dave Chinner
2020-02-28 15:47 ` Waiman Long
2020-03-15 3:46 ` Matthew Wilcox
2020-03-21 10:17 ` Konstantin Khlebnikov
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