[PATCH RT 4/7] fs: dcache: Use cpu_chill() in trylock loops
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2012-03-14 02:30:34
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Thomas Gleixner <redacted> 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 <redacted> 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