From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id BE0116B022D for ; Sat, 24 Apr 2010 14:25:08 -0400 (EDT) Message-ID: <4BD3377E.6010303@redhat.com> Date: Sat, 24 Apr 2010 21:25:02 +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> In-Reply-To: <5fa93086-b0d7-4603-bdeb-1d6bfca0cd08@default> 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 04/23/2010 07:26 PM, Dan Magenheimer wrote: >> >> Looks like "init" == open, "put_page" == write, "get_page" == read, >> "flush_page|flush_area" == trim. The only difference seems to be that >> an overwriting put_page may fail. Doesn't seem to be much of a win, >> > No, ANY put_page can fail, and this is a critical part of the API > that provides all of the flexibility for the hypervisor and all > the guests. (See previous reply.) > The guest isn't required to do any put_page()s. It can issue lots of them when memory is available, and keep them in the hypervisor forever. Failing new put_page()s isn't enough for a dynamic system, you need to be able to force the guest to give up some of its tmem. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- 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