From mboxrd@z Thu Jan 1 00:00:00 1970 From: Don Zickus Subject: Re: [PATCH 2/5] softlockup: make detector be aware of task switch of processes hogging cpu Date: Mon, 18 Aug 2014 16:38:08 -0400 Message-ID: <20140818203801.GE49576@redhat.com> References: <1407768567-171794-1-git-send-email-dzickus@redhat.com> <1407768567-171794-3-git-send-email-dzickus@redhat.com> <20140818090319.GA25495@gmail.com> <20140818150658.GQ49576@redhat.com> <20140818180158.GA4540@gmail.com> <20140818184339.GB49576@redhat.com> <20140818190200.GB5074@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: akpm@linux-foundation.org, kvm@vger.kernel.org, pbonzini@redhat.com, mingo@redhat.com, LKML , chai wen To: Ingo Molnar Return-path: Received: from mx1.redhat.com ([209.132.183.28]:5960 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751930AbaHRUiQ (ORCPT ); Mon, 18 Aug 2014 16:38:16 -0400 Content-Disposition: inline In-Reply-To: <20140818190200.GB5074@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Aug 18, 2014 at 09:02:00PM +0200, Ingo Molnar wrote: > > * Don Zickus wrote: > > > > > > So I agree with the motivation of this improvement, but > > > > > is this implementation namespace-safe? > > > > > > > > What namespace are you worried about colliding with? I > > > > thought softlockup_ would provide the safety?? Maybe I > > > > am missing something obvious. :-( > > > > > > I meant PID namespaces - a PID in itself isn't guaranteed > > > to be unique across the system. > > > > Ah, I don't think we thought about that. Is there a better > > way to do this? Is there a domain id or something that can > > be OR'd with the pid? > > What is always unique is the task pointer itself. We use pids > when we interface with user-space - but we don't really do that > here, right? No, I don't believe so. Ok, so saving 'current' and comparing that should be enough, correct? Cheers, Don