Messages in this thread Patch in this message | | | Date | Fri, 05 Apr 2013 12:47:04 +0900 | From | Masami Hiramatsu <> | Subject | Re: Re: [PATCH 3/4] uprobes/tracing: Kill the pointless local_save_flags/preempt_count calls |
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(2013/04/04 23:25), Srikar Dronamraju wrote: > * Oleg Nesterov <oleg@redhat.com> [2013-03-29 19:15:45]: > >> uprobe_trace_func() is never called with irqs or preemption >> disabled, no need to ask preempt_count() or local_save_flags(). >> >> Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > > Adding Masami in the Cc.
Thanks :), since the running context of uprobe handler is different from kprobe one, this change is only needed for uprobe.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Thank you,
> >> --- >> kernel/trace/trace_uprobe.c | 10 +++------- >> 1 files changed, 3 insertions(+), 7 deletions(-) >> >> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c >> index 8e00901..43d258d 100644 >> --- a/kernel/trace/trace_uprobe.c >> +++ b/kernel/trace/trace_uprobe.c >> @@ -492,17 +492,13 @@ static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) >> struct ring_buffer_event *event; >> struct ring_buffer *buffer; >> u8 *data; >> - int size, i, pc; >> - unsigned long irq_flags; >> + int size, i; >> struct ftrace_event_call *call = &tu->call; >> >> - local_save_flags(irq_flags); >> - pc = preempt_count(); >> - >> size = sizeof(*entry) + tu->size; >> >> event = trace_current_buffer_lock_reserve(&buffer, call->event.type, >> - size, irq_flags, pc); >> + size, 0, 0); >> if (!event) >> return 0; >> >> @@ -513,7 +509,7 @@ static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) >> call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); >> >> if (!filter_current_check_discard(buffer, call, entry, event)) >> - trace_buffer_unlock_commit(buffer, event, irq_flags, pc); >> + trace_buffer_unlock_commit(buffer, event, 0, 0); >> >> return 0; >> } >> -- >> 1.5.5.1 >> >
-- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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