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authorAlexey Klimov <alexey.klimov@linaro.org>2015-09-04 02:49:58 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2015-10-15 17:42:03 +0200
commit31f7987406497dc65408dee4e84e3f3cc3ffe9cd (patch)
tree6b72e2d6b32218b93a7b1e95c145ad2c4ff8cc0c /drivers/clocksource
parentba49af35be8a41af7f00a37902a2d70764078bc5 (diff)
downloadlinux-31f7987406497dc65408dee4e84e3f3cc3ffe9cd.tar.bz2
clocksource/drivers/exynos_mct: Use container_of() instead of this_cpu_ptr()
Since evt structure is embedded in per-CPU mevt structure it's definitely faster to use container_of() to get access to mevt if we have evt (for example as incoming function argument) instead of more expensive approach with this_cpu_ptr(&percpu_mct_tick). this_cpu_ptr() on per-CPU mevt structure leads to access to cp15 to get cpu id and arithmetic operations. Container_of() is cheaper since it's just one asm instruction. This should work if used evt pointer is correct and owned by local mevt structure. For example, before this patch set_state_shutdown() looks like: 4a4: e92d4010 push {r4, lr} 4a8: e3004000 movw r4, #0 4ac: ebfffffe bl 0 <debug_smp_processor_id> 4b0: e3003000 movw r3, #0 4b4: e3404000 movt r4, #0 4b8: e3403000 movt r3, #0 4bc: e7933100 ldr r3, [r3, r0, lsl #2] 4c0: e0844003 add r4, r4, r3 4c4: e59400c0 ldr r0, [r4, #192] ; 0xc0 4c8: ebffffd4 bl 420 <exynos4_mct_tick_stop.isra.1> 4cc: e3a00000 mov r0, #0 4d0: e8bd8010 pop {r4, pc} With this patch: 4a4: e92d4010 push {r4, lr} 4a8: e59000c0 ldr r0, [r0, #192] ; 0xc0 4ac: ebffffdb bl 420 <exynos4_mct_tick_stop.isra.1> 4b0: e3a00000 mov r0, #0 4b4: e8bd8010 pop {r4, pc} Also, for me size of exynos_mct.o decreased from 84588 bytes to 83956. Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/exynos_mct.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 029f96ab131a..ff44082a0827 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -382,24 +382,28 @@ static void exynos4_mct_tick_start(unsigned long cycles,
static int exynos4_tick_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct mct_clock_event_device *mevt;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
exynos4_mct_tick_start(cycles, mevt);
-
return 0;
}
static int set_state_shutdown(struct clock_event_device *evt)
{
- exynos4_mct_tick_stop(this_cpu_ptr(&percpu_mct_tick));
+ struct mct_clock_event_device *mevt;
+
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
+ exynos4_mct_tick_stop(mevt);
return 0;
}
static int set_state_periodic(struct clock_event_device *evt)
{
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
+ struct mct_clock_event_device *mevt;
unsigned long cycles_per_jiffy;
+ mevt = container_of(evt, struct mct_clock_event_device, evt);
cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
>> evt->shift);
exynos4_mct_tick_stop(mevt);