lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

drivers: Replace __get_cpu_var with __this_cpu_read if not used for an address.

Browse Source 
__get_cpu_var() can be replaced with this_cpu_read and will then use a single
read instruction with implied address calculation to access the correct per cpu
instance.

However, the address of a per cpu variable passed to __this_cpu_read() cannot be
determed (since its an implied address conversion through segment prefixes).
Therefore apply this only to uses of __get_cpu_var where the addres of the
variable is not used.

V3->V4:
	- Move one instance of this_cpu_inc_return to a later patch
	  so that this one can go in without percpu infrastructrure
	  changes.

Sedat: fixed compile failure caused by an extra ')'.

Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christoph Lameter 2010-12-06 11:16:24 -06:00 committed by Tejun Heo
parent 12938a9220
commit 4a6f4fe837
4 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/acpi/processor_idle.c
View File

@ -746,7 +746,7 @@ static int acpi_idle_enter_c1(struct cpuidle_device *dev,
struct acpi_processor *pr;
struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
pr = __get_cpu_var(processors);
pr = __this_cpu_read(processors);
if (unlikely(!pr))
return 0;
@ -787,7 +787,7 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
s64 idle_time_ns;
s64 idle_time;
pr = __get_cpu_var(processors);
pr = __this_cpu_read(processors);
if (unlikely(!pr))
return 0;
@ -864,7 +864,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
s64 idle_time;
pr = __get_cpu_var(processors);
pr = __this_cpu_read(processors);
if (unlikely(!pr))
return 0;

2
drivers/cpuidle/cpuidle.c
View File

@ -49,7 +49,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev);
*/
static void cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __get_cpu_var(cpuidle_devices);
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_state *target_state;
int next_state;

2
drivers/s390/cio/cio.c
View File

@ -619,7 +619,7 @@ void __irq_entry do_IRQ(struct pt_regs *regs)
s390_idle_check(regs, S390_lowcore.int_clock,
S390_lowcore.async_enter_timer);
irq_enter();
__get_cpu_var(s390_idle).nohz_delay = 1;
__this_cpu_write(s390_idle.nohz_delay, 1);
if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
/* Serve timer interrupts first. */
clock_comparator_work();

4
drivers/staging/speakup/fakekey.c
View File

@ -78,10 +78,10 @@ void speakup_fake_down_arrow(void)
/* don't change CPU */
preempt_disable();
__get_cpu_var(reporting_keystroke) = true;
__this_cpu_write(reporting_keystroke, true);
input_report_key(virt_keyboard, KEY_DOWN, PRESSED);
input_report_key(virt_keyboard, KEY_DOWN, RELEASED);
__get_cpu_var(reporting_keystroke) = false;
__this_cpu_write(reporting_keystroke, false);
/* reenable preemption */
preempt_enable();