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authorOleg Nesterov <oleg@redhat.com>2013-02-02 16:27:52 +0100
committerOleg Nesterov <oleg@redhat.com>2013-02-08 18:28:02 +0100
commitf22c1bb6b4706be3502b378cb14564449b15f983 (patch)
treeac7d09e3d42f4ab77cac56b9cb7fba2d4bcabf06 /kernel/events
parent1b47aefd9b6bd439a4be43c47acd22987ac22db8 (diff)
downloadlinux-f22c1bb6b4706be3502b378cb14564449b15f983.tar.bz2
perf: Introduce hw_perf_event->tp_target and ->tp_list
sys_perf_event_open()->perf_init_event(event) is called before find_get_context(event), this means that event->ctx == NULL when class->reg(TRACE_REG_PERF_REGISTER/OPEN) is called and thus it can't know if this event is per-task or system-wide. This patch adds hw_perf_event->tp_target for PERF_TYPE_TRACEPOINT, this is analogous to PERF_TYPE_BREAKPOINT/bp_target we already have. The patch also moves ->bp_target up so that it can overlap with the new member, this can help the compiler to generate the better code. trace_uprobe_register() will use it for prefiltering to avoid the unnecessary breakpoints in mm's we do not want to trace. ->tp_target doesn't have its own reference, but we can rely on the fact that either sys_perf_event_open() holds a reference, or it is equal to event->ctx->task. So this pointer is always valid until free_event(). Also add the "struct list_head tp_list" into this union. It is not strictly necessary, but it can simplify the next changes and we can add it for free. Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 301079d06f24..e2d4323c6ae6 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6162,11 +6162,14 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
if (task) {
event->attach_state = PERF_ATTACH_TASK;
+
+ if (attr->type == PERF_TYPE_TRACEPOINT)
+ event->hw.tp_target = task;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
/*
* hw_breakpoint is a bit difficult here..
*/
- if (attr->type == PERF_TYPE_BREAKPOINT)
+ else if (attr->type == PERF_TYPE_BREAKPOINT)
event->hw.bp_target = task;
#endif
}