Commit 1460cb65 authored by Tejun Heo's avatar Tejun Heo Committed by Ingo Molnar

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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adilger.kernel@dilger.ca
Cc: jack@suse.com
Cc: kernel-team@fb.com
Cc: mingbo@fb.com
Cc: tytso@mit.edu
Link: http://lkml.kernel.org/r/1477673892-28940-4-git-send-email-tj@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 10ab5643
...@@ -156,10 +156,12 @@ extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock, ...@@ -156,10 +156,12 @@ extern int __must_check mutex_lock_interruptible_nested(struct mutex *lock,
unsigned int subclass); unsigned int subclass);
extern int __must_check mutex_lock_killable_nested(struct mutex *lock, extern int __must_check mutex_lock_killable_nested(struct mutex *lock,
unsigned int subclass); 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(lock) mutex_lock_nested(lock, 0)
#define mutex_lock_interruptible(lock) mutex_lock_interruptible_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_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) \ #define mutex_lock_nest_lock(lock, nest_lock) \
do { \ do { \
...@@ -171,11 +173,13 @@ do { \ ...@@ -171,11 +173,13 @@ do { \
extern void mutex_lock(struct mutex *lock); extern void mutex_lock(struct mutex *lock);
extern int __must_check mutex_lock_interruptible(struct mutex *lock); extern int __must_check mutex_lock_interruptible(struct mutex *lock);
extern int __must_check mutex_lock_killable(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_nested(lock, subclass) mutex_lock(lock)
# define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(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_killable_nested(lock, subclass) mutex_lock_killable(lock)
# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock) # define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
# define mutex_lock_nest_io(lock, nest_lock) mutex_io(lock)
#endif #endif
/* /*
......
...@@ -783,6 +783,20 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass) ...@@ -783,6 +783,20 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
} }
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested); 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 static inline int
ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) 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) ...@@ -950,6 +964,16 @@ int __sched mutex_lock_killable(struct mutex *lock)
} }
EXPORT_SYMBOL(mutex_lock_killable); 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 static noinline void __sched
__mutex_lock_slowpath(struct mutex *lock) __mutex_lock_slowpath(struct mutex *lock)
{ {
......
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