From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id BB36A6B01D0 for ; Tue, 15 Jun 2010 03:11:40 -0400 (EDT) Message-ID: <4C1727A9.9040606@redhat.com> Date: Tue, 15 Jun 2010 10:11:37 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [RFC/T/D][PATCH 2/2] Linux/Guest cooperative unmapped page cache control References: <20100608155140.3749.74418.sendpatchset@L34Z31A.ibm.com> <20100608155153.3749.31669.sendpatchset@L34Z31A.ibm.com> <4C10B3AF.7020908@redhat.com> <20100610142512.GB5191@balbir.in.ibm.com> <1276214852.6437.1427.camel@nimitz> <20100611045600.GE5191@balbir.in.ibm.com> <4C15E3C8.20407@redhat.com> <20100614084810.GT5191@balbir.in.ibm.com> <1276528376.6437.7176.camel@nimitz> <4C164C22.1050503@redhat.com> <20100614174008.GA5191@balbir.in.ibm.com> In-Reply-To: <20100614174008.GA5191@balbir.in.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com Cc: Dave Hansen , kvm , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On 06/14/2010 08:40 PM, Balbir Singh wrote: > * Avi Kivity [2010-06-14 18:34:58]: > > >> On 06/14/2010 06:12 PM, Dave Hansen wrote: >> >>> On Mon, 2010-06-14 at 14:18 +0530, Balbir Singh wrote: >>> >>>> 1. A slab page will not be freed until the entire page is free (all >>>> slabs have been kfree'd so to speak). Normal reclaim will definitely >>>> free this page, but a lot of it depends on how frequently we are >>>> scanning the LRU list and when this page got added. >>>> >>> You don't have to be freeing entire slab pages for the reclaim to have >>> been useful. You could just be making space so that _future_ >>> allocations fill in the slab holes you just created. You may not be >>> freeing pages, but you're reducing future system pressure. >>> >> Depends. If you've evicted something that will be referenced soon, >> you're increasing system pressure. >> >> > I don't think slab pages care about being referenced soon, they are > either allocated or freed. A page is just a storage unit for the data > structure. A new one can be allocated on demand. > If we're talking just about slab pages, I agree. If we're applying pressure on the shrinkers, then you are removing live objects which can be costly to reinstantiate. -- error compiling committee.c: too many arguments to function -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org