Keep a record of how many mutexes are held by any task. This allows cpu
scheduler code to use this information in decision making for tasks that
hold contended resources.
Signed-off-by: Con Kolivas <[email protected]>
---
include/linux/init_task.h | 1 +
include/linux/sched.h | 1 +
kernel/fork.c | 1 +
kernel/mutex.c | 25 +++++++++++++++++++++++--
4 files changed, 26 insertions(+), 2 deletions(-)
Index: linux-ck-dev/include/linux/init_task.h
===================================================================
--- linux-ck-dev.orig/include/linux/init_task.h 2006-06-18 15:20:14.000000000 +1000
+++ linux-ck-dev/include/linux/init_task.h 2006-06-18 15:23:44.000000000 +1000
@@ -120,6 +120,7 @@ extern struct group_info init_groups;
.blocked = {{0}}, \
.alloc_lock = SPIN_LOCK_UNLOCKED, \
.proc_lock = SPIN_LOCK_UNLOCKED, \
+ .mutexes_held = 0, \
.journal_info = NULL, \
.cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
.fs_excl = ATOMIC_INIT(0), \
Index: linux-ck-dev/include/linux/sched.h
===================================================================
--- linux-ck-dev.orig/include/linux/sched.h 2006-06-18 15:23:38.000000000 +1000
+++ linux-ck-dev/include/linux/sched.h 2006-06-18 15:23:44.000000000 +1000
@@ -845,6 +845,7 @@ struct task_struct {
/* mutex deadlock detection */
struct mutex_waiter *blocked_on;
#endif
+ unsigned long mutexes_held;
/* journalling filesystem info */
void *journal_info;
Index: linux-ck-dev/kernel/fork.c
===================================================================
--- linux-ck-dev.orig/kernel/fork.c 2006-06-18 15:20:14.000000000 +1000
+++ linux-ck-dev/kernel/fork.c 2006-06-18 15:23:44.000000000 +1000
@@ -1022,6 +1022,7 @@ static task_t *copy_process(unsigned lon
p->io_context = NULL;
p->io_wait = NULL;
p->audit_context = NULL;
+ p->mutexes_held = 0;
cpuset_fork(p);
#ifdef CONFIG_NUMA
p->mempolicy = mpol_copy(p->mempolicy);
Index: linux-ck-dev/kernel/mutex.c
===================================================================
--- linux-ck-dev.orig/kernel/mutex.c 2006-06-18 15:20:14.000000000 +1000
+++ linux-ck-dev/kernel/mutex.c 2006-06-18 15:23:44.000000000 +1000
@@ -58,6 +58,16 @@ EXPORT_SYMBOL(__mutex_init);
static void fastcall noinline __sched
__mutex_lock_slowpath(atomic_t *lock_count __IP_DECL__);
+static inline void inc_mutex_count(void)
+{
+ current->mutexes_held++;
+}
+
+static inline void dec_mutex_count(void)
+{
+ current->mutexes_held--;
+}
+
/***
* mutex_lock - acquire the mutex
* @lock: the mutex to be acquired
@@ -87,6 +97,7 @@ void fastcall __sched mutex_lock(struct
* 'unlocked' into 'locked' state.
*/
__mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
+ inc_mutex_count();
}
EXPORT_SYMBOL(mutex_lock);
@@ -112,6 +123,7 @@ void fastcall __sched mutex_unlock(struc
* into 'unlocked' state:
*/
__mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
+ dec_mutex_count();
}
EXPORT_SYMBOL(mutex_unlock);
@@ -254,9 +266,14 @@ __mutex_lock_interruptible_slowpath(atom
*/
int fastcall __sched mutex_lock_interruptible(struct mutex *lock)
{
+ int ret;
+
might_sleep();
- return __mutex_fastpath_lock_retval
+ ret = __mutex_fastpath_lock_retval
(&lock->count, __mutex_lock_interruptible_slowpath);
+ if (likely(!ret))
+ inc_mutex_count();
+ return ret;
}
EXPORT_SYMBOL(mutex_lock_interruptible);
@@ -308,8 +325,12 @@ static inline int __mutex_trylock_slowpa
*/
int fastcall mutex_trylock(struct mutex *lock)
{
- return __mutex_fastpath_trylock(&lock->count,
+ int ret = __mutex_fastpath_trylock(&lock->count,
__mutex_trylock_slowpath);
+
+ if (likely(ret))
+ inc_mutex_count();
+ return ret;
}
EXPORT_SYMBOL(mutex_trylock);
--
-ck
-
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