From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761834Ab3DDOa7 (ORCPT ); Thu, 4 Apr 2013 10:30:59 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:48282 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761158Ab3DDOa6 (ORCPT ); Thu, 4 Apr 2013 10:30:58 -0400 Date: Thu, 4 Apr 2013 19:55:22 +0530 From: Srikar Dronamraju To: Oleg Nesterov Cc: Ananth N Mavinakayanahalli , Steven Rostedt , Anton Arapov , Frederic Weisbecker , Ingo Molnar , linux-kernel@vger.kernel.org, Masami Hiramatsu Subject: Re: [PATCH 3/4] uprobes/tracing: Kill the pointless local_save_flags/preempt_count calls Message-ID: <20130404142522.GC8986@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20130329181520.GA20670@redhat.com> <20130329181545.GA20697@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20130329181545.GA20697@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13040414-5806-0000-0000-000020987F64 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov [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 Acked-by: Srikar Dronamraju Adding Masami in the Cc. > --- > 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 > -- Thanks and Regards Srikar Dronamraju