From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 0D9B26B01E3 for ; Sun, 25 Apr 2010 09:18:57 -0400 (EDT) Message-ID: <4BD4413D.5030808@redhat.com> Date: Sun, 25 Apr 2010 16:18:53 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: Frontswap [PATCH 0/4] (was Transcendent Memory): overview References: <20100422134249.GA2963@ca-server1.us.oracle.com> <4BD06B31.9050306@redhat.com> <53c81c97-b30f-4081-91a1-7cef1879c6fa@default> <4BD07594.9080905@redhat.com> <4BD16D09.2030803@redhat.com> <4BD1A74A.2050003@redhat.com> <4830bd20-77b7-46c8-994b-8b4fa9a79d27@default> <4BD1B427.9010905@redhat.com> <4BD1B626.7020702@redhat.com> <5fa93086-b0d7-4603-bdeb-1d6bfca0cd08@default> <4BD3377E.6010303@redhat.com> <1c02a94a-a6aa-4cbb-a2e6-9d4647760e91@default 4BD43033.7090706@redhat.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Dan Magenheimer Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jeremy@goop.org, hugh.dickins@tiscali.co.uk, ngupta@vflare.org, JBeulich@novell.com, chris.mason@oracle.com, kurt.hackel@oracle.com, dave.mccracken@oracle.com, npiggin@suse.de, akpm@linux-foundation.org, riel@redhat.com List-ID: On 04/25/2010 04:12 PM, Dan Magenheimer wrote: >> >> In this case you could use the same mechanism to stop new put_page()s? >> > You are suggesting the hypervisor communicate dynamically-rapidly-changing > physical memory availability information to a userland daemon in each guest, > and each daemon communicate this information to each respective kernel > to notify the kernel that hypervisor memory is not available? > > Seems very convoluted to me, and anyway it doesn't eliminate the need > for a hook placed exactly where the frontswap_put hook is placed. > Yeah, it's pretty ugly. Balloons typically communicate without a daemon too. >> Seems frontswap is like a reverse balloon, where the balloon is in >> hypervisor space instead of the guest space. >> > That's a reasonable analogy. Frontswap serves nicely as an > emergency safety valve when a guest has given up (too) much of > its memory via ballooning but unexpectedly has an urgent need > that can't be serviced quickly enough by the balloon driver. > (or ordinary swap) -- 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