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perf_counter: generalize pending infrastructure

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Prepare the pending infrastructure to do more than wakeups.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094517.634732847@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-04-06 11:45:02 +02:00 committed by Ingo Molnar
parent 3c446b3d3b
commit 671dec5daf
2 changed files with 36 additions and 24 deletions
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7
include/linux/perf_counter.h
View File

@ -321,8 +321,9 @@ struct perf_mmap_data {
void *data_pages[0];
};
struct perf_wakeup_entry {
struct perf_wakeup_entry *next;
struct perf_pending_entry {
struct perf_pending_entry *next;
void (*func)(struct perf_pending_entry *);
};
/**
@ -401,7 +402,7 @@ struct perf_counter {
wait_queue_head_t waitq;
struct fasync_struct *fasync;
/* optional: for NMIs */
struct perf_wakeup_entry wakeup;
struct perf_pending_entry pending;
void (*destroy)(struct perf_counter *);
struct rcu_head rcu_head;

53
kernel/perf_counter.c
View File

@ -1581,6 +1581,14 @@ void perf_counter_wakeup(struct perf_counter *counter)
kill_fasync(&counter->fasync, SIGIO, POLL_IN);
}
static void perf_pending_wakeup(struct perf_pending_entry *entry)
{
struct perf_counter *counter = container_of(entry,
struct perf_counter, pending);
perf_counter_wakeup(counter);
}
/*
* Pending wakeups
*
@ -1590,45 +1598,47 @@ void perf_counter_wakeup(struct perf_counter *counter)
* single linked list and use cmpxchg() to add entries lockless.
*/
#define PENDING_TAIL ((struct perf_wakeup_entry *)-1UL)
#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
static DEFINE_PER_CPU(struct perf_wakeup_entry *, perf_wakeup_head) = {
static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
PENDING_TAIL,
};
static void perf_pending_queue(struct perf_counter *counter)
static void perf_pending_queue(struct perf_pending_entry *entry,
void (*func)(struct perf_pending_entry *))
{
struct perf_wakeup_entry **head;
struct perf_wakeup_entry *prev, *next;
struct perf_pending_entry **head;
if (cmpxchg(&counter->wakeup.next, NULL, PENDING_TAIL) != NULL)
if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
return;
head = &get_cpu_var(perf_wakeup_head);
entry->func = func;
head = &get_cpu_var(perf_pending_head);
do {
prev = counter->wakeup.next = *head;
next = &counter->wakeup;
} while (cmpxchg(head, prev, next) != prev);
entry->next = *head;
} while (cmpxchg(head, entry->next, entry) != entry->next);
set_perf_counter_pending();
put_cpu_var(perf_wakeup_head);
put_cpu_var(perf_pending_head);
}
static int __perf_pending_run(void)
{
struct perf_wakeup_entry *list;
struct perf_pending_entry *list;
int nr = 0;
list = xchg(&__get_cpu_var(perf_wakeup_head), PENDING_TAIL);
list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
while (list != PENDING_TAIL) {
struct perf_counter *counter = container_of(list,
struct perf_counter, wakeup);
void (*func)(struct perf_pending_entry *);
struct perf_pending_entry *entry = list;
list = list->next;
counter->wakeup.next = NULL;
func = entry->func;
entry->next = NULL;
/*
* Ensure we observe the unqueue before we issue the wakeup,
* so that we won't be waiting forever.
@ -1636,7 +1646,7 @@ static int __perf_pending_run(void)
*/
smp_wmb();
perf_counter_wakeup(counter);
func(entry);
nr++;
}
@ -1658,7 +1668,7 @@ static inline int perf_not_pending(struct perf_counter *counter)
* so that we do not miss the wakeup. -- see perf_pending_handle()
*/
smp_rmb();
return counter->wakeup.next == NULL;
return counter->pending.next == NULL;
}
static void perf_pending_sync(struct perf_counter *counter)
@ -1695,9 +1705,10 @@ struct perf_output_handle {
static inline void __perf_output_wakeup(struct perf_output_handle *handle)
{
if (handle->nmi)
perf_pending_queue(handle->counter);
else
if (handle->nmi) {
perf_pending_queue(&handle->counter->pending,
perf_pending_wakeup);
} else
perf_counter_wakeup(handle->counter);
}