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sched, perf: Use a single callback into the scheduler 

We can easily use a single callback for both sched-in and sched-out. This
reduces the code footprint in the scheduler path as well as removes
the PMU black spot otherwise present between the out and in callback.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-o56ajxp1edwqg6x9d31wb805@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2012-05-08 18:56:04 +02:00 committed by Ingo Molnar
parent 8b1e13638d
commit cb04ff9ac4
3 changed files with 17 additions and 30 deletions
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24
include/linux/perf_event.h
View File

@ -1084,10 +1084,8 @@ extern void perf_pmu_unregister(struct pmu *pmu);
extern int perf_num_counters(void);
extern const char *perf_pmu_name(void);
extern void __perf_event_task_sched_in(struct task_struct *prev,
struct task_struct *task);
extern void __perf_event_task_sched_out(struct task_struct *prev,
struct task_struct *next);
extern void __perf_event_task_sched(struct task_struct *prev,
struct task_struct *next);
extern int perf_event_init_task(struct task_struct *child);
extern void perf_event_exit_task(struct task_struct *child);
extern void perf_event_free_task(struct task_struct *task);
@ -1207,20 +1205,13 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
extern struct static_key_deferred perf_sched_events;
static inline void perf_event_task_sched_in(struct task_struct *prev,
static inline void perf_event_task_sched(struct task_struct *prev,
struct task_struct *task)
{
if (static_key_false(&perf_sched_events.key))
__perf_event_task_sched_in(prev, task);
}
static inline void perf_event_task_sched_out(struct task_struct *prev,
struct task_struct *next)
{
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, NULL, 0);
if (static_key_false(&perf_sched_events.key))
__perf_event_task_sched_out(prev, next);
__perf_event_task_sched(prev, task);
}
extern void perf_event_mmap(struct vm_area_struct *vma);
@ -1295,11 +1286,8 @@ extern void perf_event_disable(struct perf_event *event);
extern void perf_event_task_tick(void);
#else
static inline void
perf_event_task_sched_in(struct task_struct *prev,
struct task_struct *task) { }
static inline void
perf_event_task_sched_out(struct task_struct *prev,
struct task_struct *next) { }
perf_event_task_sched(struct task_struct *prev,
struct task_struct *task) { }
static inline int perf_event_init_task(struct task_struct *child) { return 0; }
static inline void perf_event_exit_task(struct task_struct *child) { }
static inline void perf_event_free_task(struct task_struct *task) { }

14
kernel/events/core.c
View File

@ -2039,8 +2039,8 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
* accessing the event control register. If a NMI hits, then it will
* not restart the event.
*/
void __perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next)
static void __perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next)
{
int ctxn;
@ -2279,8 +2279,8 @@ static void perf_branch_stack_sched_in(struct task_struct *prev,
* accessing the event control register. If a NMI hits, then it will
* keep the event running.
*/
void __perf_event_task_sched_in(struct task_struct *prev,
struct task_struct *task)
static void __perf_event_task_sched_in(struct task_struct *prev,
struct task_struct *task)
{
struct perf_event_context *ctx;
int ctxn;
@ -2305,6 +2305,12 @@ void __perf_event_task_sched_in(struct task_struct *prev,
perf_branch_stack_sched_in(prev, task);
}
void __perf_event_task_sched(struct task_struct *prev, struct task_struct *next)
{
__perf_event_task_sched_out(prev, next);
__perf_event_task_sched_in(prev, next);
}
static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
{
u64 frequency = event->attr.sample_freq;

9
kernel/sched/core.c
View File

@ -1913,7 +1913,7 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
sched_info_switch(prev, next);
perf_event_task_sched_out(prev, next);
perf_event_task_sched(prev, next);
fire_sched_out_preempt_notifiers(prev, next);
prepare_lock_switch(rq, next);
prepare_arch_switch(next);
@ -1956,13 +1956,6 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
*/
prev_state = prev->state;
finish_arch_switch(prev);
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
local_irq_disable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
perf_event_task_sched_in(prev, current);
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
local_irq_enable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
finish_lock_switch(rq, prev);
finish_arch_post_lock_switch();