The patch titled
rtmutex: Propagate priority settings into PI lock chains
has been added to the -mm tree. Its filename is
rtmutex-propagate-priority-settings-into-pi-lock-chains.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: rtmutex: Propagate priority settings into PI lock chains
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
When the priority of a task, which is blocked on a lock, changes we must
propagate this change into the PI lock chain. Therefor the chain walk code
is changed to get rid of the references to current to avoid false positives
in the deadlock detector, as setscheduler might be called by a task which
holds the lock on which the task whose priority is changed is blocked.
Also add some comments about the get/put_task_struct usage to avoid
confusion.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/sched.h | 2 +
kernel/rtmutex.c | 42 ++++++++++++++++++++++++++++++++++------
kernel/sched.c | 2 +
3 files changed, 40 insertions(+), 6 deletions(-)
diff -puN include/linux/sched.h~rtmutex-propagate-priority-settings-into-pi-lock-chains include/linux/sched.h
--- a/include/linux/sched.h~rtmutex-propagate-priority-settings-into-pi-lock-chains
+++ a/include/linux/sched.h
@@ -1110,11 +1110,13 @@ extern void sched_idle_next(void);
#ifdef CONFIG_RT_MUTEXES
extern int rt_mutex_getprio(task_t *p);
extern void rt_mutex_setprio(task_t *p, int prio);
+extern void rt_mutex_adjust_pi(task_t *p);
#else
static inline int rt_mutex_getprio(task_t *p)
{
return p->normal_prio;
}
+# define rt_mutex_adjust_pi(p) do { } while (0)
#endif
extern void set_user_nice(task_t *p, long nice);
diff -puN kernel/rtmutex.c~rtmutex-propagate-priority-settings-into-pi-lock-chains kernel/rtmutex.c
--- a/kernel/rtmutex.c~rtmutex-propagate-priority-settings-into-pi-lock-chains
+++ a/kernel/rtmutex.c
@@ -160,7 +160,8 @@ int max_lock_depth = 1024;
static int rt_mutex_adjust_prio_chain(task_t *task,
int deadlock_detect,
struct rt_mutex *orig_lock,
- struct rt_mutex_waiter *orig_waiter
+ struct rt_mutex_waiter *orig_waiter,
+ struct task_struct *top_task
__IP_DECL__)
{
struct rt_mutex *lock;
@@ -189,7 +190,7 @@ static int rt_mutex_adjust_prio_chain(ta
prev_max = max_lock_depth;
printk(KERN_WARNING "Maximum lock depth %d reached "
"task: %s (%d)\n", max_lock_depth,
- current->comm, current->pid);
+ top_task->comm, top_task->pid);
}
put_task_struct(task);
@@ -229,7 +230,7 @@ static int rt_mutex_adjust_prio_chain(ta
}
/* Deadlock detection */
- if (lock == orig_lock || rt_mutex_owner(lock) == current) {
+ if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
spin_unlock(&lock->wait_lock);
ret = deadlock_detect ? -EDEADLK : 0;
@@ -433,6 +434,7 @@ static int task_blocks_on_rt_mutex(struc
__rt_mutex_adjust_prio(owner);
if (owner->pi_blocked_on) {
boost = 1;
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
get_task_struct(owner);
}
spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -441,6 +443,7 @@ static int task_blocks_on_rt_mutex(struc
spin_lock_irqsave(&owner->pi_lock, flags);
if (owner->pi_blocked_on) {
boost = 1;
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
get_task_struct(owner);
}
spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -450,8 +453,8 @@ static int task_blocks_on_rt_mutex(struc
spin_unlock(&lock->wait_lock);
- res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock,
- waiter __IP__);
+ res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
+ current __IP__);
spin_lock(&lock->wait_lock);
@@ -552,6 +555,7 @@ static void remove_waiter(struct rt_mute
if (owner->pi_blocked_on) {
boost = 1;
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
get_task_struct(owner);
}
spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -564,12 +568,37 @@ static void remove_waiter(struct rt_mute
spin_unlock(&lock->wait_lock);
- rt_mutex_adjust_prio_chain(owner, 0, lock, NULL __IP__);
+ rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current __IP__);
spin_lock(&lock->wait_lock);
}
/*
+ * Recheck the pi chain, in case we got a priority setting
+ *
+ * Called from sched_setscheduler
+ */
+void rt_mutex_adjust_pi(struct task_struct *task)
+{
+ struct rt_mutex_waiter *waiter;
+ unsigned long flags;
+
+ spin_lock_irqsave(&task->pi_lock, flags);
+
+ waiter = task->pi_blocked_on;
+ if (!waiter || waiter->list_entry.prio == task->prio) {
+ spin_unlock_irqrestore(&task->pi_lock, flags);
+ return;
+ }
+
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
+ get_task_struct(task);
+ spin_unlock_irqrestore(&task->pi_lock, flags);
+
+ rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
+}
+
+/*
* Slow path lock function:
*/
static int __sched
@@ -636,6 +665,7 @@ rt_mutex_slowlock(struct rt_mutex *lock,
if (unlikely(ret))
break;
}
+
spin_unlock(&lock->wait_lock);
debug_rt_mutex_print_deadlock(&waiter);
diff -puN kernel/sched.c~rtmutex-propagate-priority-settings-into-pi-lock-chains kernel/sched.c
--- a/kernel/sched.c~rtmutex-propagate-priority-settings-into-pi-lock-chains
+++ a/kernel/sched.c
@@ -4096,6 +4096,8 @@ recheck:
__task_rq_unlock(rq);
spin_unlock_irqrestore(&p->pi_lock, flags);
+ rt_mutex_adjust_pi(p);
+
return 0;
}
EXPORT_SYMBOL_GPL(sched_setscheduler);
_
Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are
origin.patch
git-mtd.patch
pi-futex-futex-code-cleanups.patch
pi-futex-introduce-debug_check_no_locks_freed.patch
pi-futex-add-plist-implementation.patch
pi-futex-scheduler-support-for-pi.patch
pi-futex-rt-mutex-core.patch
pi-futex-rt-mutex-docs.patch
pi-futex-rt-mutex-debug.patch
pi-futex-rt-mutex-tester.patch
pi-futex-rt-mutex-tester-fix.patch
pi-futex-rt-mutex-futex-api.patch
pi-futex-futex_lock_pi-futex_unlock_pi-support.patch
fix-rt-mutex-defaults-and-dependencies.patch
drop-tasklist-lock-in-do_sched_setscheduler.patch
rtmutex-propagate-priority-settings-into-pi-lock-chains.patch
futex_requeue-optimization.patch
genirq-rename-desc-handler-to-desc-chip.patch
genirq-rename-desc-handler-to-desc-chip-terminate_irqs-fix.patch
genirq-sem2mutex-probe_sem-probing_active.patch
genirq-cleanup-merge-irq_affinity-into-irq_desc.patch
genirq-cleanup-remove-irq_descp.patch
genirq-cleanup-remove-fastcall.patch
genirq-cleanup-misc-code-cleanups.patch
genirq-cleanup-reduce-irq_desc_t-use-mark-it-obsolete.patch
genirq-cleanup-include-linux-irqh.patch
genirq-cleanup-merge-irq_dir-smp_affinity_entry-into-irq_desc.patch
genirq-cleanup-merge-pending_irq_cpumask-into-irq_desc.patch
genirq-cleanup-turn-arch_has_irq_per_cpu-into-config_irq_per_cpu.patch
genirq-debug-better-debug-printout-in-enable_irq.patch
genirq-add-retrigger-irq-op-to-consolidate-hw_irq_resend.patch
genirq-doc-comment-include-linux-irqh-structures.patch
genirq-doc-handle_irq_event-and-__do_irq-comments.patch
genirq-cleanup-no_irq_type-cleanups.patch
genirq-doc-add-design-documentation.patch
genirq-add-genirq-sw-irq-retrigger.patch
genirq-add-irq_noprobe-support.patch
genirq-add-irq_norequest-support.patch
genirq-add-irq_noautoen-support.patch
genirq-update-copyrights.patch
genirq-core.patch
genirq-msi-fixes-2.patch
genirq-add-irq-chip-support.patch
genirq-add-irq-chip-support-fix.patch
genirq-add-irq-chip-support-fasteoi-handler-handle-interrupt-disabling.patch
genirq-convert-the-x86_64-architecture-to-irq-chips.patch
genirq-convert-the-i386-architecture-to-irq-chips.patch
genirq-convert-the-i386-architecture-to-irq-chips-fix-2.patch
genirq-add-chip-eoi-fastack-fasteoi-fix.patch
genirq-add-handle_bad_irq.patch
genirq-add-irq-wake-power-management-support.patch
genirq-add-sa_trigger-support.patch
genirq-more-verbose-debugging-on-unexpected-irq-vectors.patch
genirq-ia64-build-fix.patch
genirq-add-irq_type_sense_mask.patch
genirq-irq-convert-the-move_irq-flag-from-a-32bit-word-to-a-single-bit.patch
genirq-irq-add-moved_masked_irq.patch
genirq-x86_64-irq-reenable-migrating-irqs-to-other-cpus.patch
genirq-msi-simplify-msi-enable-and-disable.patch
genirq-msi-simplify-msi-enable-and-disable-fix.patch
genirq-msi-make-the-msi-boolean-tests-return-either-0-or-1.patch
genirq-msi-implement-helper-functions-read_msi_msg-and-write_msi_msg.patch
genirq-msi-refactor-the-msi_ops.patch
genirq-msi-simplify-the-msi-irq-limit-policy.patch
genirq-irq-add-a-dynamic-irq-creation-api.patch
genirq-ia64-irq-dynamic-irq-support.patch
genirq-i386-irq-dynamic-irq-support.patch
genirq-i386-irq-dynamic-irq-support-fix.patch
genirq-x86_64-irq-dynamic-irq-support.patch
genirq-msi-make-the-msi-code-irq-based-and-not-vector-based.patch
genirq-x86_64-irq-move-msi-message-composition-into-io_apicc.patch
genirq-i386-irq-move-msi-message-composition-into-io_apicc.patch
genirq-msi-only-build-msi-apicc-on-ia64.patch
genirq-x86_64-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-i386-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-i386-irq-remove-the-msi-assumption-that-irq-==-vector-fix.patch
genirq-irq-remove-msi-hacks.patch
genirq-irq-generalize-the-check-for-hardirq_bits.patch
genirq-x86_64-irq-make-the-external-irq-handlers-report-their-vector-not-the-irq-number.patch
genirq-x86_64-irq-make-vector_irq-per-cpu.patch
genirq-x86_64-irq-kill-gsi_irq_sharing.patch
genirq-x86_64-irq-kill-irq-compression.patch
genirq-irq-document-what-an-irq-is.patch
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