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 ESMTP id B34A16B002D for ; Tue, 15 Nov 2011 12:33:44 -0500 (EST) Message-ID: <4EC2A274.8080801@goop.org> Date: Tue, 15 Nov 2011 09:33:40 -0800 From: Jeremy Fitzhardinge MIME-Version: 1.0 Subject: Re: [GIT PULL] mm: frontswap (for 3.2 window) References: <75efb251-7a5e-4aca-91e2-f85627090363@default> <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@default 4EB1AD53.2000600@redhat.com> <4EC29367.9040106@redhat.com> In-Reply-To: <4EC29367.9040106@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Dan Magenheimer , Andrea Arcangeli , Pekka Enberg , Cyclonus J , Sasha Levin , Christoph Hellwig , David Rientjes , Linus Torvalds , linux-mm@kvack.org, LKML , Andrew Morton , Konrad Wilk , Seth Jennings , ngupta@vflare.org, Chris Mason , JBeulich@novell.com, Dave Hansen , Jonathan Corbet 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.) J -- 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