119 lines
3.1 KiB
Diff
119 lines
3.1 KiB
Diff
From 6f05fc5bb3de3c6dd109a5d166d8c44c92464377 Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 7 Mar 2012 21:00:34 +0100
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Subject: [PATCH 219/365] fs: dcache: Use cpu_chill() in trylock loops
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Retry loops on RT might loop forever when the modifying side was
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preempted. Use cpu_chill() instead of cpu_relax() to let the system
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make progress.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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fs/autofs4/autofs_i.h | 1 +
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fs/autofs4/expire.c | 2 +-
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fs/dcache.c | 20 ++++++++++++++++----
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fs/namespace.c | 3 ++-
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4 files changed, 20 insertions(+), 6 deletions(-)
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diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
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index 42f863346409..e4deae2d9fa1 100644
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--- a/fs/autofs4/autofs_i.h
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+++ b/fs/autofs4/autofs_i.h
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@@ -32,6 +32,7 @@
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#include <linux/sched.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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+#include <linux/delay.h>
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#include <asm/current.h>
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#include <linux/uaccess.h>
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diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
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index 02f0d373adbf..1454264c8c1a 100644
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--- a/fs/autofs4/expire.c
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+++ b/fs/autofs4/expire.c
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@@ -148,7 +148,7 @@ static struct dentry *get_next_positive_dentry(struct dentry *prev,
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parent = p->d_parent;
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if (!spin_trylock(&parent->d_lock)) {
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spin_unlock(&p->d_lock);
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- cpu_relax();
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+ cpu_chill();
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goto relock;
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}
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spin_unlock(&p->d_lock);
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diff --git a/fs/dcache.c b/fs/dcache.c
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index ed0a023a0567..f757c63e36a6 100644
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--- a/fs/dcache.c
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+++ b/fs/dcache.c
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@@ -19,6 +19,7 @@
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/fsnotify.h>
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+#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/hash.h>
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@@ -787,6 +788,8 @@ static inline bool fast_dput(struct dentry *dentry)
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*/
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void dput(struct dentry *dentry)
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{
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+ struct dentry *parent;
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+
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if (unlikely(!dentry))
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return;
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@@ -825,9 +828,18 @@ void dput(struct dentry *dentry)
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return;
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kill_it:
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- dentry = dentry_kill(dentry);
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- if (dentry) {
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- cond_resched();
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+ parent = dentry_kill(dentry);
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+ if (parent) {
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+ int r;
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+
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+ if (parent == dentry) {
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+ /* the task with the highest priority won't schedule */
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+ r = cond_resched();
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+ if (!r)
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+ cpu_chill();
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+ } else {
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+ dentry = parent;
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+ }
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goto repeat;
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}
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}
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@@ -2380,7 +2392,7 @@ void d_delete(struct dentry * dentry)
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if (dentry->d_lockref.count == 1) {
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if (!spin_trylock(&inode->i_lock)) {
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spin_unlock(&dentry->d_lock);
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- cpu_relax();
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+ cpu_chill();
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goto again;
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}
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dentry->d_flags &= ~DCACHE_CANT_MOUNT;
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diff --git a/fs/namespace.c b/fs/namespace.c
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index 3f5b81c194ab..6d5149dc7667 100644
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--- a/fs/namespace.c
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+++ b/fs/namespace.c
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@@ -14,6 +14,7 @@
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#include <linux/mnt_namespace.h>
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#include <linux/user_namespace.h>
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#include <linux/namei.h>
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+#include <linux/delay.h>
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#include <linux/security.h>
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#include <linux/idr.h>
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#include <linux/init.h> /* init_rootfs */
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@@ -360,7 +361,7 @@ int __mnt_want_write(struct vfsmount *m)
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smp_mb();
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while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
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preempt_enable();
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- cpu_relax();
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+ cpu_chill();
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preempt_disable();
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}
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/*
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--
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2.28.0
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