The patch titled
hrtimers: simplify lockdep stuff
has been added to the -mm tree. Its filename is
hrtimers-simplify-lockdep-stuff.patch
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See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: hrtimers: simplify lockdep stuff
From: Oleg Nesterov <oleg@xxxxxxxxxx>
In order to avoid the false positive from lockdep, each per-cpu base->lock has
the separate lock class and migrate_hrtimers() uses double_spin_lock().
This is overcomplicated: except for migrate_hrtimers() we never take 2 locks
at once, and migrate_hrtimers() can use spin_lock_nested().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hrtimer.h | 2 --
kernel/hrtimer.c | 9 ++++-----
2 files changed, 4 insertions(+), 7 deletions(-)
diff -puN include/linux/hrtimer.h~hrtimers-simplify-lockdep-stuff include/linux/hrtimer.h
--- a/include/linux/hrtimer.h~hrtimers-simplify-lockdep-stuff
+++ a/include/linux/hrtimer.h
@@ -173,7 +173,6 @@ struct hrtimer_clock_base {
* struct hrtimer_cpu_base - the per cpu clock bases
* @lock: lock protecting the base and associated clock bases
* and timers
- * @lock_key: the lock_class_key for use with lockdep
* @clock_base: array of clock bases for this cpu
* @curr_timer: the timer which is executing a callback right now
* @expires_next: absolute time of the next event which was scheduled
@@ -189,7 +188,6 @@ struct hrtimer_clock_base {
*/
struct hrtimer_cpu_base {
spinlock_t lock;
- struct lock_class_key lock_key;
struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
struct list_head cb_pending;
#ifdef CONFIG_HIGH_RES_TIMERS
diff -puN kernel/hrtimer.c~hrtimers-simplify-lockdep-stuff kernel/hrtimer.c
--- a/kernel/hrtimer.c~hrtimers-simplify-lockdep-stuff
+++ a/kernel/hrtimer.c
@@ -1420,7 +1420,6 @@ static void __cpuinit init_hrtimers_cpu(
int i;
spin_lock_init(&cpu_base->lock);
- lockdep_set_class(&cpu_base->lock, &cpu_base->lock_key);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
cpu_base->clock_base[i].cpu_base = cpu_base;
@@ -1461,16 +1460,16 @@ static void migrate_hrtimers(int cpu)
tick_cancel_sched_timer(cpu);
local_irq_disable();
- double_spin_lock(&new_base->lock, &old_base->lock,
- smp_processor_id() < cpu);
+ spin_lock(&new_base->lock);
+ spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
migrate_hrtimer_list(&old_base->clock_base[i],
&new_base->clock_base[i]);
}
- double_spin_unlock(&new_base->lock, &old_base->lock,
- smp_processor_id() < cpu);
+ spin_unlock(&old_base->lock);
+ spin_unlock(&new_base->lock);
local_irq_enable();
put_cpu_var(hrtimer_bases);
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
mmap_region-cleanup-the-final-vma_merge-related-code.patch
remove-unused-variable-from-send_signal.patch
turn-legacy_queue-macro-into-static-inline-function.patch
consolidate-checking-for-ignored-legacy-signals.patch
consolidate-checking-for-ignored-legacy-signals-simplify.patch
signals-do_signal_stop-use-signal_group_exit.patch
timers-simplify-lockdep-stuff.patch
hrtimers-simplify-lockdep-stuff.patch
kill-double_spin_lock.patch
procfs-task-exe-symlink.patch
procfs-task-exe-symlink-fix.patch
-
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