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perf: Complete software pmu grouping

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Aside from allowing software events into a !software group,
allow adding !software events to pure software groups.

Once we've moved the software group and attached the first
!software event, the group will no longer be a pure software
group and hence no longer be eligible for movement, at which
point the straight ctx comparison is correct again.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20100917093009.410784731@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-09-17 11:28:48 +02:00 committed by Ingo Molnar
parent d14b12d7ad
commit b04243ef70
2 changed files with 66 additions and 5 deletions
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6
include/linux/perf_event.h
View File

@ -804,12 +804,18 @@ struct perf_event {
#endif /* CONFIG_PERF_EVENTS */
};
enum perf_event_context_type {
task_context,
cpu_context,
};
/**
* struct perf_event_context - event context structure
*
* Used as a container for task events and CPU events as well:
*/
struct perf_event_context {
enum perf_event_context_type type;
struct pmu *pmu;
/*
* Protect the states of the events in the list,

65
kernel/perf_event.c
View File

@ -5184,6 +5184,7 @@ int perf_pmu_register(struct pmu *pmu)
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
__perf_event_init_context(&cpuctx->ctx);
cpuctx->ctx.type = cpu_context;
cpuctx->ctx.pmu = pmu;
cpuctx->timer_interval = TICK_NSEC;
hrtimer_init(&cpuctx->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
@ -5517,7 +5518,8 @@ SYSCALL_DEFINE5(perf_event_open,
struct perf_event_attr __user *, attr_uptr,
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
{
struct perf_event *event, *group_leader = NULL, *output_event = NULL;
struct perf_event *group_leader = NULL, *output_event = NULL;
struct perf_event *event, *sibling;
struct perf_event_attr attr;
struct perf_event_context *ctx;
struct file *event_file = NULL;
@ -5525,6 +5527,7 @@ SYSCALL_DEFINE5(perf_event_open,
struct task_struct *task = NULL;
struct pmu *pmu;
int event_fd;
int move_group = 0;
int fput_needed = 0;
int err;
@ -5574,8 +5577,29 @@ SYSCALL_DEFINE5(perf_event_open,
* any hardware group.
*/
pmu = event->pmu;
if ((pmu->task_ctx_nr == perf_sw_context) && group_leader)
pmu = group_leader->pmu;
if (group_leader &&
(is_software_event(event) != is_software_event(group_leader))) {
if (is_software_event(event)) {
/*
* If event and group_leader are not both a software
* event, and event is, then group leader is not.
*
* Allow the addition of software events to !software
* groups, this is safe because software events never
* fail to schedule.
*/
pmu = group_leader->pmu;
} else if (is_software_event(group_leader) &&
(group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
/*
* In case the group is a pure software group, and we
* try to add a hardware event, move the whole group to
* the hardware context.
*/
move_group = 1;
}
}
if (pid != -1)
task = find_lively_task_by_vpid(pid);
@ -5605,8 +5629,14 @@ SYSCALL_DEFINE5(perf_event_open,
* Do not allow to attach to a group in a different
* task or CPU context:
*/
if (group_leader->ctx != ctx)
goto err_context;
if (move_group) {
if (group_leader->ctx->type != ctx->type)
goto err_context;
} else {
if (group_leader->ctx != ctx)
goto err_context;
}
/*
* Only a group leader can be exclusive or pinned
*/
@ -5626,9 +5656,34 @@ SYSCALL_DEFINE5(perf_event_open,
goto err_context;
}
if (move_group) {
struct perf_event_context *gctx = group_leader->ctx;
mutex_lock(&gctx->mutex);
perf_event_remove_from_context(group_leader);
list_for_each_entry(sibling, &group_leader->sibling_list,
group_entry) {
perf_event_remove_from_context(sibling);
put_ctx(gctx);
}
mutex_unlock(&gctx->mutex);
put_ctx(gctx);
}
event->filp = event_file;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
if (move_group) {
perf_install_in_context(ctx, group_leader, cpu);
get_ctx(ctx);
list_for_each_entry(sibling, &group_leader->sibling_list,
group_entry) {
perf_install_in_context(ctx, sibling, cpu);
get_ctx(ctx);
}
}
perf_install_in_context(ctx, event, cpu);
++ctx->generation;
mutex_unlock(&ctx->mutex);