Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752766AbaA2QHZ (ORCPT ); Wed, 29 Jan 2014 11:07:25 -0500 Received: from mail-la0-f54.google.com ([209.85.215.54]:42150 "EHLO mail-la0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751341AbaA2QHY (ORCPT ); Wed, 29 Jan 2014 11:07:24 -0500 MIME-Version: 1.0 In-Reply-To: <20140129145535.GA12562@redhat.com> References: <1390895840.8373.2.camel@beeld> <20140128164320.GB7596@redhat.com> <20140129145535.GA12562@redhat.com> Date: Wed, 29 Jan 2014 22:07:22 +0600 Message-ID: Subject: Re: Do we really need curr_target in signal_struct ? From: Rakib Mullick To: Oleg Nesterov Cc: LKML , Ingo Molnar , Andrew Morton Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 29, 2014 at 8:55 PM, Oleg Nesterov wrote: > On 01/29, Rakib Mullick wrote: >> >> On Tue, Jan 28, 2014 at 10:43 PM, Oleg Nesterov wrote: >> > >> AFAIU, ->current_target is only a loop breaker to avoid infinite loop, > > No. It caches the last result of "find a thread which can handle this > group-wide signal". > The reason behind of my understanding is the following comments: /* * No thread needs to be woken. * Any eligible threads will see * the signal in the queue soon. */ What if, there's no thread in a group wants_signal()? Or it can't practically happen? >> but - by using while_each_thread() we can remove it completely, thus >> helps to get rid from maintaining it too. > > ... and remove the optimization above. > >> I'll prepare a proper patch with you suggestions for reviewing. > > I am not sure we want this patch. Once again, I do not know how much > ->curr_target helps, and certainaly it can't help always. But you > should not blindly remove it just because yes, sure, it is not strictly > needed to find a wants_signal() thread. > Are you thinking that , since things are not broken, then we shouldn't try to do anything? Thanks, Rakib -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/