Commit-ID: 1460cb65a10f6c7a6e3a1c76513338861a0a43b6
Gitweb: http://git.kernel.org/tip/1460cb65a10f6c7a6e3a1c76513338861a0a43b6
Author: Tejun Heo <tj@xxxxxxxxxx>
AuthorDate: Fri, 28 Oct 2016 12:58:11 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sat, 14 Jan 2017 11:30:05 +0100
locking/mutex, sched/wait: Add mutex_lock_io()
We sometimes end up propagating IO blocking through mutexes; however,
because there currently is no way of annotating mutex sleeps as
iowait, there are cases where iowait and /proc/stat:procs_blocked
report misleading numbers obscuring the actual state of the system.
This patch adds mutex_lock_io() so that mutex sleeps can be marked as
iowait in those cases.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: adilger.kernel@xxxxxxxxx
Cc: jack@xxxxxxxx
Cc: kernel-team@xxxxxx
Cc: mingbo@xxxxxx
Cc: tytso@xxxxxxx
Link: http://lkml.kernel.org/r/1477673892-28940-4-git-send-email-tj@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/mutex.h | 4 ++++
kernel/locking/mutex.c | 24 ++++++++++++++++++++++++
2 files changed, 28 insertions(+)
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index b97870f..980ba16 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -156,10 +156,12 @@ extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock,
unsigned int subclass);
extern int __must_check mutex_lock_killable_nested(struct mutex *lock,
unsigned int subclass);
+extern void mutex_lock_io_nested(struct mutex *lock, unsigned int subclass);
#define mutex_lock(lock) mutex_lock_nested(lock, 0)
#define mutex_lock_interruptible(lock) mutex_lock_interruptible_nested(lock, 0)
#define mutex_lock_killable(lock) mutex_lock_killable_nested(lock, 0)
+#define mutex_lock_io(lock) mutex_lock_io_nested(lock, 0)
#define mutex_lock_nest_lock(lock, nest_lock) \
do { \
@@ -171,11 +173,13 @@ do { \
extern void mutex_lock(struct mutex *lock);
extern int __must_check mutex_lock_interruptible(struct mutex *lock);
extern int __must_check mutex_lock_killable(struct mutex *lock);
+extern void mutex_lock_io(struct mutex *lock);
# define mutex_lock_nested(lock, subclass) mutex_lock(lock)
# define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock)
# define mutex_lock_killable_nested(lock, subclass) mutex_lock_killable(lock)
# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
+# define mutex_lock_nest_io(lock, nest_lock) mutex_io(lock)
#endif
/*
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 9b34961..8464a5c 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -783,6 +783,20 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
}
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
+void __sched
+mutex_lock_io_nested(struct mutex *lock, unsigned int subclass)
+{
+ int token;
+
+ might_sleep();
+
+ token = io_schedule_prepare();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
+ subclass, NULL, _RET_IP_, NULL, 0);
+ io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_io_nested);
+
static inline int
ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
@@ -950,6 +964,16 @@ int __sched mutex_lock_killable(struct mutex *lock)
}
EXPORT_SYMBOL(mutex_lock_killable);
+void __sched mutex_lock_io(struct mutex *lock)
+{
+ int token;
+
+ token = io_schedule_prepare();
+ mutex_lock(lock);
+ io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_io);
+
static noinline void __sched
__mutex_lock_slowpath(struct mutex *lock)
{
--
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