From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
stable-rt@vger.kernel.org
Subject: [PATCH RT 4/7] fs: dcache: Use cpu_chill() in trylock loops
Date: Tue, 13 Mar 2012 22:27:02 -0400 [thread overview]
Message-ID: <20120314022945.223176076@goodmis.org> (raw)
In-Reply-To: 20120314022658.783312660@goodmis.org
[-- Attachment #1: 0004-fs-dcache-Use-cpu_chill-in-trylock-loops.patch --]
[-- Type: text/plain, Size: 2160 bytes --]
From: Thomas Gleixner <tglx@linutronix.de>
Retry loops on RT might loop forever when the modifying side was
preempted. Use cpu_chill() instead of cpu_relax() to let the system
make progress.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
fs/autofs4/autofs_i.h | 1 +
fs/autofs4/expire.c | 2 +-
fs/dcache.c | 7 ++++---
3 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index b620114..83424ab 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -34,6 +34,7 @@
#include <linux/sched.h>
#include <linux/mount.h>
#include <linux/namei.h>
+#include <linux/delay.h>
#include <asm/current.h>
#include <asm/uaccess.h>
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index d8b6184..f4abda3 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -170,7 +170,7 @@ again:
parent = p->d_parent;
if (!seq_spin_trylock(&parent->d_lock)) {
seq_spin_unlock(&p->d_lock);
- cpu_relax();
+ cpu_chill();
goto relock;
}
seq_spin_unlock(&p->d_lock);
diff --git a/fs/dcache.c b/fs/dcache.c
index 10580be..eedf276 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -36,6 +36,7 @@
#include <linux/bit_spinlock.h>
#include <linux/rculist_bl.h>
#include <linux/prefetch.h>
+#include <linux/delay.h>
#include "internal.h"
/*
@@ -360,7 +361,7 @@ static inline struct dentry *dentry_kill(struct dentry *dentry, int ref)
if (inode && !spin_trylock(&inode->i_lock)) {
relock:
seq_spin_unlock(&dentry->d_lock);
- cpu_relax();
+ cpu_chill();
return dentry; /* try again with same dentry */
}
if (IS_ROOT(dentry))
@@ -738,7 +739,7 @@ relock:
if (!seq_spin_trylock(&dentry->d_lock)) {
spin_unlock(&dcache_lru_lock);
- cpu_relax();
+ cpu_chill();
goto relock;
}
@@ -2053,7 +2054,7 @@ again:
if (dentry->d_count == 1) {
if (inode && !spin_trylock(&inode->i_lock)) {
seq_spin_unlock(&dentry->d_lock);
- cpu_relax();
+ cpu_chill();
goto again;
}
dentry->d_flags &= ~DCACHE_CANT_MOUNT;
--
1.7.8.3
next prev parent reply other threads:[~2012-03-14 2:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-14 2:26 [PATCH RT 0/7] [ANNOUNCE] 3.0.23-rt40-rc1 Steven Rostedt
2012-03-14 2:26 ` [PATCH RT 1/7] Revert "ACPI: Convert embedded controller lock to raw spinlock" Steven Rostedt
2012-03-14 2:27 ` [PATCH RT 2/7] softirq: Check preemption after reenabling interrupts Steven Rostedt
2012-03-14 2:27 ` [PATCH RT 3/7] rt: Introduce cpu_chill() Steven Rostedt
2012-03-14 2:27 ` Steven Rostedt [this message]
2012-03-14 2:27 ` [PATCH RT 5/7] fs: namespace: Use cpu_chill() instead of cpu_relax() Steven Rostedt
2012-03-14 2:27 ` [PATCH RT 6/7] net: " Steven Rostedt
2012-03-14 2:27 ` [PATCH RT 7/7] Linux 3.0.23-rt40-rc1 Steven Rostedt
2012-03-14 12:52 ` [PATCH RT 0/7] [ANNOUNCE] 3.0.23-rt40-rc1 Karsten Wiese
2012-03-14 15:14 ` Steven Rostedt
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=20120314022945.223176076@goodmis.org \
--to=rostedt@goodmis.org \
--cc=C.Emde@osadl.org \
--cc=jkacur@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=stable-rt@vger.kernel.org \
--cc=tglx@linutronix.de \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).