From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id D048D6B002D for ; Wed, 16 Nov 2011 09:51:31 -0500 (EST) Date: Wed, 16 Nov 2011 09:49:59 -0500 From: Konrad Rzeszutek Wilk Subject: Re: [GIT PULL] mm: frontswap (for 3.2 window) Message-ID: <20111116144959.GA11487@phenom.dumpdata.com> References: <20111027215243.GA31644@infradead.org> <1319785956.3235.7.camel@lappy> <552d2067-474d-4aef-a9a4-89e5fd8ef84f@default20111031181651.GF3466@redhat.com> <60592afd-97aa-4eaf-b86b-f6695d31c7f1@default> <20111031223717.GI3466@redhat.com> <1b2e4f74-7058-4712-85a7-84198723e3ee@default4EB1AD53.2000600@redhat.com> <4EC29367.9040106@redhat.com> <4EC2A274.8080801@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4EC2A274.8080801@goop.org> Sender: owner-linux-mm@kvack.org List-ID: To: Jeremy Fitzhardinge Cc: Rik van Riel , Dan Magenheimer , Andrea Arcangeli , Pekka Enberg , Cyclonus J , Sasha Levin , Christoph Hellwig , David Rientjes , Linus Torvalds , linux-mm@kvack.org, LKML , Andrew Morton , Seth Jennings , ngupta@vflare.org, Chris Mason , JBeulich@novell.com, Dave Hansen , Jonathan Corbet On Tue, Nov 15, 2011 at 09:33:40AM -0800, Jeremy Fitzhardinge wrote: > On 11/15/2011 08:29 AM, Rik van Riel wrote: > > On 11/02/2011 05:14 PM, Dan Magenheimer wrote: > > > >> It occurs to me that batching could be done locally without > >> changing the in-kernel "API" (i.e. frontswap_ops)... the > >> guest-side KVM tmem-backend-driver could do the compression > >> into guest-side memory and make a single > >> hypercall=vmexit/vmenter whenever it has collected enough for > >> a batch. > > > > That seems like the best way to do it, indeed. > > > > Do the current hooks allow that mode of operation, > > or do the hooks only return after the entire operation > > has completed? > > The APIs are synchronous, but need only return once the memory has been > dealt with in some way. If you were batching before making a hypercall, > then the implementation would just have to make a copy into its private > memory and you'd have to make sure that lookups on batched but > unsubmitted pages work. > > (It's been a while since I've looked at these patches, but I'm assuming > nothing fundamental has changed about them lately.) Yup, what you describe is possible, and nothing fundamental has changed about them. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org