From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takuya Yoshikawa Subject: Re: [RFC] need to improve slot creation/destruction? -- Re: [RFC][PATCH] srcu: Implement call_srcu() Date: Fri, 10 Feb 2012 22:08:12 +0900 Message-ID: <20120210220812.4e2e3a30c7fddf72d4e6e8af@gmail.com> References: <1328016724.2446.229.camel@twins> <4F27F0E6.1040309@redhat.com> <1328017807.2446.230.camel@twins> <20120131222447.GH2391@linux.vnet.ibm.com> <1328091749.2760.34.camel@laptop> <4F29178A.1090306@redhat.com> <4F2918D5.4050104@redhat.com> <20120201135020.GB18998@amt.cnet> <20120209004320.5772daa0472aef4700dab1b6@gmail.com> <4F33D6C9.2070403@redhat.com> <4F33D711.6020104@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:57195 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754220Ab2BJNIR (ORCPT ); Fri, 10 Feb 2012 08:08:17 -0500 Received: by iacb35 with SMTP id b35so257642iac.19 for ; Fri, 10 Feb 2012 05:08:16 -0800 (PST) In-Reply-To: <4F33D711.6020104@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > On 02/09/2012 04:23 PM, Avi Kivity wrote: > > > BTW do we really need fast slot creation/destruction? > > > > Not really, but it's good to have infrastructure that copes with > > different workloads. If the patches keep the code simple I think it's a > > good thing to have. My patch is pretty simple. > To qualify - taking several tens of milliseconds is out of the question > as some workloads grind to a halt. But it doesn't need to be incredibly > fast. I think the problem is not how long it takes to create/invalidate a slot but following faults and shadow pages reconstruction. Similar to mmu shrinker problem we discussed before. E.g. users will not expect sudden latency induced by pci hotplug. Takuya