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percpu: use raw_local_irq_* in _this_cpu op

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It doesn't make sense to trace irq off or do irq flags
lock proving inside 'this_cpu' operations, so replace local_irq_*
with raw_local_irq_* in 'this_cpu' op.

Also the patch fixes onelockdep warning[1] by the replacement, see
below:

In commit: 933393f58fef9963eac61db8093689544e29a600(percpu:
Remove irqsafe_cpu_xxx variants), local_irq_save/restore(flags) are
added inside this_cpu_inc operation, so that trace_hardirqs_off_caller
will be called by trace_hardirqs_on_caller directly because
__debug_atomic_inc is implemented as this_cpu_inc, which may trigger
the lockdep warning[1], for example in the below ARM scenary:

	kernel_thread_helper	/*irq disabled*/
		->trace_hardirqs_on_caller	/*hardirqs_enabled was set*/
			->trace_hardirqs_off_caller	/*hardirqs_enabled cleared*/
				__this_cpu_add(redundant_hardirqs_on)
			->trace_hardirqs_off_caller	/*irq disabled, so call here*/

The 'unannotated irqs-on' warning will be triggered somewhere because
irq is just enabled after the irq trace in kernel_thread_helper.

[1],
[    0.162841] ------------[ cut here ]------------
[    0.167694] WARNING: at kernel/lockdep.c:3493 check_flags+0xc0/0x1d0()
[    0.174468] Modules linked in:
[    0.177703] Backtrace:
[    0.180328] [<c00171f0>] (dump_backtrace+0x0/0x110) from [<c0412320>] (dump_stack+0x18/0x1c)
[    0.189086]  r6:c051f778 r5:00000da5 r4:00000000 r3:60000093
[    0.195007] [<c0412308>] (dump_stack+0x0/0x1c) from [<c00410e8>] (warn_slowpath_common+0x54/0x6c)
[    0.204223] [<c0041094>] (warn_slowpath_common+0x0/0x6c) from [<c0041124>] (warn_slowpath_null+0x24/0x2c)
[    0.214111]  r8:00000000 r7:00000000 r6:ee069598 r5:60000013 r4:ee082000
[    0.220825] r3:00000009
[    0.223693] [<c0041100>] (warn_slowpath_null+0x0/0x2c) from [<c0088f38>] (check_flags+0xc0/0x1d0)
[    0.232910] [<c0088e78>] (check_flags+0x0/0x1d0) from [<c008d348>] (lock_acquire+0x4c/0x11c)
[    0.241668] [<c008d2fc>] (lock_acquire+0x0/0x11c) from [<c0415aa4>] (_raw_spin_lock+0x3c/0x74)
[    0.250610] [<c0415a68>] (_raw_spin_lock+0x0/0x74) from [<c010a844>] (set_task_comm+0x20/0xc0)
[    0.259521]  r6:ee069588 r5:ee0691c0 r4:ee082000
[    0.264404] [<c010a824>] (set_task_comm+0x0/0xc0) from [<c0060780>] (kthreadd+0x28/0x108)
[    0.272857]  r8:00000000 r7:00000013 r6:c0044a08 r5:ee0691c0 r4:ee082000
[    0.279571] r3:ee083fe0
[    0.282470] [<c0060758>] (kthreadd+0x0/0x108) from [<c0044a08>] (do_exit+0x0/0x6dc)
[    0.290405]  r5:c0060758 r4:00000000
[    0.294189] ---[ end trace 1b75b31a2719ed1c ]---
[    0.299041] possible reason: unannotated irqs-on.
[    0.303955] irq event stamp: 5
[    0.307159] hardirqs last  enabled at (4): [<c001331c>] no_work_pending+0x8/0x2c
[    0.314880] hardirqs last disabled at (5): [<c0089b08>] trace_hardirqs_on_caller+0x60/0x26c
[    0.323547] softirqs last  enabled at (0): [<c003f754>] copy_process+0x33c/0xef4
[    0.331207] softirqs last disabled at (0): [<  (null)>]   (null)
[    0.337585] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Ming Lei 2012-02-15 16:54:38 +08:00 committed by Tejun Heo
parent 7d96b3e55a
commit e920d5971d
1 changed files with 10 additions and 10 deletions
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20
include/linux/percpu.h
View File

@ -348,9 +348,9 @@ do { \
#define _this_cpu_generic_to_op(pcp, val, op) \
do { \
unsigned long flags; \
local_irq_save(flags); \
raw_local_irq_save(flags); \
*__this_cpu_ptr(&(pcp)) op val; \
local_irq_restore(flags); \
raw_local_irq_restore(flags); \
} while (0)
#ifndef this_cpu_write
@ -449,10 +449,10 @@ do { \
({ \
typeof(pcp) ret__; \
unsigned long flags; \
local_irq_save(flags); \
raw_local_irq_save(flags); \
__this_cpu_add(pcp, val); \
ret__ = __this_cpu_read(pcp); \
local_irq_restore(flags); \
raw_local_irq_restore(flags); \
ret__; \
})
@ -479,10 +479,10 @@ do { \
#define _this_cpu_generic_xchg(pcp, nval) \
({ typeof(pcp) ret__; \
unsigned long flags; \
local_irq_save(flags); \
raw_local_irq_save(flags); \
ret__ = __this_cpu_read(pcp); \
__this_cpu_write(pcp, nval); \
local_irq_restore(flags); \
raw_local_irq_restore(flags); \
ret__; \
})
@ -507,11 +507,11 @@ do { \
({ \
typeof(pcp) ret__; \
unsigned long flags; \
local_irq_save(flags); \
raw_local_irq_save(flags); \
ret__ = __this_cpu_read(pcp); \
if (ret__ == (oval)) \
__this_cpu_write(pcp, nval); \
local_irq_restore(flags); \
raw_local_irq_restore(flags); \
ret__; \
})
@ -544,10 +544,10 @@ do { \
({ \
int ret__; \
unsigned long flags; \
local_irq_save(flags); \
raw_local_irq_save(flags); \
ret__ = __this_cpu_generic_cmpxchg_double(pcp1, pcp2, \
oval1, oval2, nval1, nval2); \
local_irq_restore(flags); \
raw_local_irq_restore(flags); \
ret__; \
})