summaryrefslogtreecommitdiff
path: root/kernel/locking
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-05-17 00:47:16 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-17 00:47:16 +0300
commit825a3b2605c3aa193e0075d0f9c72e33c17ab16a (patch)
treee8665c4cc20076ae53165475839d36b4bc641cd3 /kernel/locking
parentcf6ed9a6682d3f171cf9550d4bbe0ef31b768a7e (diff)
parentef0491ea17f8019821c7e9c8e801184ecf17f85a (diff)
downloadlinux-825a3b2605c3aa193e0075d0f9c72e33c17ab16a.tar.xz
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar: - massive CPU hotplug rework (Thomas Gleixner) - improve migration fairness (Peter Zijlstra) - CPU load calculation updates/cleanups (Yuyang Du) - cpufreq updates (Steve Muckle) - nohz optimizations (Frederic Weisbecker) - switch_mm() micro-optimization on x86 (Andy Lutomirski) - ... lots of other enhancements, fixes and cleanups. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (66 commits) ARM: Hide finish_arch_post_lock_switch() from modules sched/core: Provide a tsk_nr_cpus_allowed() helper sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowed sched/loadavg: Fix loadavg artifacts on fully idle and on fully loaded systems sched/fair: Correct unit of load_above_capacity sched/fair: Clean up scale confusion sched/nohz: Fix affine unpinned timers mess sched/fair: Fix fairness issue on migration sched/core: Kill sched_class::task_waking to clean up the migration logic sched/fair: Prepare to fix fairness problems on migration sched/fair: Move record_wakee() sched/core: Fix comment typo in wake_q_add() sched/core: Remove unused variable sched: Make hrtick_notifier an explicit call sched/fair: Make ilb_notifier an explicit call sched/hotplug: Make activate() the last hotplug step sched/hotplug: Move migration CPU_DYING to sched_cpu_dying() sched/migration: Move CPU_ONLINE into scheduler state sched/migration: Move calc_load_migrate() into CPU_DYING sched/migration: Move prepare transition to SCHED_STARTING state ...
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/lockdep.c71
1 files changed, 62 insertions, 9 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 874d53eaf389..81f1a7107c0e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -45,6 +45,7 @@
#include <linux/bitops.h>
#include <linux/gfp.h>
#include <linux/kmemcheck.h>
+#include <linux/random.h>
#include <asm/sections.h>
@@ -3585,7 +3586,35 @@ static int __lock_is_held(struct lockdep_map *lock)
return 0;
}
-static void __lock_pin_lock(struct lockdep_map *lock)
+static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
+{
+ struct pin_cookie cookie = NIL_COOKIE;
+ struct task_struct *curr = current;
+ int i;
+
+ if (unlikely(!debug_locks))
+ return cookie;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ struct held_lock *hlock = curr->held_locks + i;
+
+ if (match_held_lock(hlock, lock)) {
+ /*
+ * Grab 16bits of randomness; this is sufficient to not
+ * be guessable and still allows some pin nesting in
+ * our u32 pin_count.
+ */
+ cookie.val = 1 + (prandom_u32() >> 16);
+ hlock->pin_count += cookie.val;
+ return cookie;
+ }
+ }
+
+ WARN(1, "pinning an unheld lock\n");
+ return cookie;
+}
+
+static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
struct task_struct *curr = current;
int i;
@@ -3597,7 +3626,7 @@ static void __lock_pin_lock(struct lockdep_map *lock)
struct held_lock *hlock = curr->held_locks + i;
if (match_held_lock(hlock, lock)) {
- hlock->pin_count++;
+ hlock->pin_count += cookie.val;
return;
}
}
@@ -3605,7 +3634,7 @@ static void __lock_pin_lock(struct lockdep_map *lock)
WARN(1, "pinning an unheld lock\n");
}
-static void __lock_unpin_lock(struct lockdep_map *lock)
+static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
struct task_struct *curr = current;
int i;
@@ -3620,7 +3649,11 @@ static void __lock_unpin_lock(struct lockdep_map *lock)
if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
return;
- hlock->pin_count--;
+ hlock->pin_count -= cookie.val;
+
+ if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n"))
+ hlock->pin_count = 0;
+
return;
}
}
@@ -3751,24 +3784,44 @@ int lock_is_held(struct lockdep_map *lock)
}
EXPORT_SYMBOL_GPL(lock_is_held);
-void lock_pin_lock(struct lockdep_map *lock)
+struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
{
+ struct pin_cookie cookie = NIL_COOKIE;
unsigned long flags;
if (unlikely(current->lockdep_recursion))
- return;
+ return cookie;
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion = 1;
- __lock_pin_lock(lock);
+ cookie = __lock_pin_lock(lock);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
+
+ return cookie;
}
EXPORT_SYMBOL_GPL(lock_pin_lock);
-void lock_unpin_lock(struct lockdep_map *lock)
+void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
+{
+ unsigned long flags;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ __lock_repin_lock(lock, cookie);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_repin_lock);
+
+void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
unsigned long flags;
@@ -3779,7 +3832,7 @@ void lock_unpin_lock(struct lockdep_map *lock)
check_flags(flags);
current->lockdep_recursion = 1;
- __lock_unpin_lock(lock);
+ __lock_unpin_lock(lock, cookie);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}