The patch titled
timers: simplify lockdep stuff
has been added to the -mm tree. Its filename is
timers-simplify-lockdep-stuff.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: timers: 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_timers() uses double_spin_lock().
This all is overcomplicated: except for migrate_timers() we never take 2 locks
at once, and migrate_timers() 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>
---
kernel/timer.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff -puN kernel/timer.c~timers-simplify-lockdep-stuff kernel/timer.c
--- a/kernel/timer.c~timers-simplify-lockdep-stuff
+++ a/kernel/timer.c
@@ -1220,13 +1220,6 @@ asmlinkage long sys_sysinfo(struct sysin
return 0;
}
-/*
- * lockdep: we want to track each per-CPU base as a separate lock-class,
- * but timer-bases are kmalloc()-ed, so we need to attach separate
- * keys to them:
- */
-static struct lock_class_key base_lock_keys[NR_CPUS];
-
static int __cpuinit init_timers_cpu(int cpu)
{
int j;
@@ -1269,7 +1262,6 @@ static int __cpuinit init_timers_cpu(int
}
spin_lock_init(&base->lock);
- lockdep_set_class(&base->lock, base_lock_keys + cpu);
for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j);
@@ -1308,8 +1300,8 @@ static void __cpuinit migrate_timers(int
new_base = get_cpu_var(tvec_bases);
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);
BUG_ON(old_base->running_timer);
@@ -1322,8 +1314,8 @@ static void __cpuinit migrate_timers(int
migrate_timer_list(new_base, old_base->tv5.vec + 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(tvec_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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