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author | Oleg Nesterov <oleg@redhat.com> | 2013-02-03 19:58:35 (GMT) |
---|---|---|
committer | Oleg Nesterov <oleg@redhat.com> | 2013-02-08 17:28:06 (GMT) |
commit | 736288ba5016e255869c26296014eeff649971c2 (patch) | |
tree | 235ab829ec63136e19d97a817489484f88ad3da8 /kernel/trace | |
parent | bdf8647c44766590ed02f9a84a450a796558b753 (diff) | |
download | linux-fsl-qoriq-736288ba5016e255869c26296014eeff649971c2.tar.xz |
uprobes/perf: Teach trace_uprobe/perf code to track the active perf_event's
Introduce "struct trace_uprobe_filter" which records the "active"
perf_event's attached to ftrace_event_call. For the start we simply
use list_head, we can optimize this later if needed. For example, we
do not really need to record an event with ->parent != NULL, we can
rely on parent->child_list. And we can certainly do some optimizations
for the case when 2 events have the same ->tp_target or tp_target->mm.
Change trace_uprobe_register() to process TRACE_REG_PERF_OPEN/CLOSE
and add/del this perf_event to the list.
We can probably avoid any locking, but lets start with the "obvioulsy
correct" trace_uprobe_filter->rwlock which protects everything.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/trace')
-rw-r--r-- | kernel/trace/trace_uprobe.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index c4e29e1..2a74a93 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -28,6 +28,12 @@ #define UPROBE_EVENT_SYSTEM "uprobes" +struct trace_uprobe_filter { + rwlock_t rwlock; + int nr_systemwide; + struct list_head perf_events; +}; + /* * uprobe event core functions */ @@ -35,6 +41,7 @@ struct trace_uprobe { struct list_head list; struct ftrace_event_class class; struct ftrace_event_call call; + struct trace_uprobe_filter filter; struct uprobe_consumer consumer; struct inode *inode; char *filename; @@ -58,6 +65,18 @@ static LIST_HEAD(uprobe_list); static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); +static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) +{ + rwlock_init(&filter->rwlock); + filter->nr_systemwide = 0; + INIT_LIST_HEAD(&filter->perf_events); +} + +static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) +{ + return !filter->nr_systemwide && list_empty(&filter->perf_events); +} + /* * Allocate new trace_uprobe and initialize it (including uprobes). */ @@ -87,6 +106,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs) INIT_LIST_HEAD(&tu->list); tu->consumer.handler = uprobe_dispatcher; + init_trace_uprobe_filter(&tu->filter); return tu; error: @@ -544,6 +564,8 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag) if (is_trace_uprobe_enabled(tu)) return -EINTR; + WARN_ON(!uprobe_filter_is_empty(&tu->filter)); + tu->flags |= flag; ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); if (ret) @@ -557,6 +579,8 @@ static void probe_event_disable(struct trace_uprobe *tu, int flag) if (!is_trace_uprobe_enabled(tu)) return; + WARN_ON(!uprobe_filter_is_empty(&tu->filter)); + uprobe_unregister(tu->inode, tu->offset, &tu->consumer); tu->flags &= ~flag; } @@ -632,6 +656,30 @@ static int set_print_fmt(struct trace_uprobe *tu) } #ifdef CONFIG_PERF_EVENTS +static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) +{ + write_lock(&tu->filter.rwlock); + if (event->hw.tp_target) + list_add(&event->hw.tp_list, &tu->filter.perf_events); + else + tu->filter.nr_systemwide++; + write_unlock(&tu->filter.rwlock); + + return 0; +} + +static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) +{ + write_lock(&tu->filter.rwlock); + if (event->hw.tp_target) + list_del(&event->hw.tp_list); + else + tu->filter.nr_systemwide--; + write_unlock(&tu->filter.rwlock); + + return 0; +} + /* uprobe profile handler */ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) { @@ -687,6 +735,13 @@ int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, case TRACE_REG_PERF_UNREGISTER: probe_event_disable(tu, TP_FLAG_PROFILE); return 0; + + case TRACE_REG_PERF_OPEN: + return uprobe_perf_open(tu, data); + + case TRACE_REG_PERF_CLOSE: + return uprobe_perf_close(tu, data); + #endif default: return 0; |