diff options
Diffstat (limited to 'debian/patches-rt/0187-fs-dcache-Use-cpu_chill-in-trylock-loops.patch')
| -rw-r--r-- | debian/patches-rt/0187-fs-dcache-Use-cpu_chill-in-trylock-loops.patch | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/debian/patches-rt/0187-fs-dcache-Use-cpu_chill-in-trylock-loops.patch b/debian/patches-rt/0187-fs-dcache-Use-cpu_chill-in-trylock-loops.patch new file mode 100644 index 000000000..2df32b031 --- /dev/null +++ b/debian/patches-rt/0187-fs-dcache-Use-cpu_chill-in-trylock-loops.patch @@ -0,0 +1,66 @@ +From d12da2a9ddfd2e6803327ef9856a63caedb4c653 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Wed, 7 Mar 2012 21:00:34 +0100 +Subject: [PATCH 187/347] fs: dcache: Use cpu_chill() in trylock loops +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +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> +--- + fs/autofs/expire.c | 3 ++- + fs/namespace.c | 8 ++++++-- + 2 files changed, 8 insertions(+), 3 deletions(-) + +diff --git a/fs/autofs/expire.c b/fs/autofs/expire.c +index 70e9afe589fb..1a6b88ad4fe0 100644 +--- a/fs/autofs/expire.c ++++ b/fs/autofs/expire.c +@@ -8,6 +8,7 @@ + * option, any later version, incorporated herein by reference. + */ + ++#include <linux/delay.h> + #include "autofs_i.h" + + /* Check if a dentry can be expired */ +@@ -153,7 +154,7 @@ static struct dentry *get_next_positive_dentry(struct dentry *prev, + parent = p->d_parent; + if (!spin_trylock(&parent->d_lock)) { + spin_unlock(&p->d_lock); +- cpu_relax(); ++ cpu_chill(); + goto relock; + } + spin_unlock(&p->d_lock); +diff --git a/fs/namespace.c b/fs/namespace.c +index 396ff1bcfdad..2c0ff275e978 100644 +--- a/fs/namespace.c ++++ b/fs/namespace.c +@@ -14,6 +14,7 @@ + #include <linux/mnt_namespace.h> + #include <linux/user_namespace.h> + #include <linux/namei.h> ++#include <linux/delay.h> + #include <linux/security.h> + #include <linux/cred.h> + #include <linux/idr.h> +@@ -327,8 +328,11 @@ int __mnt_want_write(struct vfsmount *m) + * incremented count after it has set MNT_WRITE_HOLD. + */ + smp_mb(); +- while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) +- cpu_relax(); ++ while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) { ++ preempt_enable(); ++ cpu_chill(); ++ preempt_disable(); ++ } + /* + * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will + * be set to match its requirements. So we must not load that until +-- +2.36.1 + |