Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755147Ab0DVNqB (ORCPT ); Thu, 22 Apr 2010 09:46:01 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:26930 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754944Ab0DVNp6 (ORCPT ); Thu, 22 Apr 2010 09:45:58 -0400 Date: Thu, 22 Apr 2010 06:44:09 -0700 From: Dan Magenheimer To: 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 Subject: Frontswap [PATCH 4/4] (was Transcendent Memory): config files Message-ID: <20100422134409.GA3078@ca-server1.us.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-11) X-Auth-Type: Internal IP X-Source-IP: acsinet15.oracle.com [141.146.126.227] X-CT-RefId: str=0001.0A090208.4BD052CE.00A6:SCFMA922111,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2182 Lines: 49 Frontswap [PATCH 4/4] (was Transcendent Memory): config files Frontswap config defaults to on as the hooks devolve to pointer-compare-to-NULL if no frontswap backend is provided. Signed-off-by: Dan Magenheimer Diffstat: Kconfig | 16 ++++++++++++++++ Makefile | 1 + 2 files changed, 17 insertions(+) --- linux-2.6.34-rc5/mm/Makefile 2010-04-19 17:29:56.000000000 -0600 +++ linux-2.6.34-rc5-frontswap/mm/Makefile 2010-04-21 09:17:37.000000000 -0600 @@ -17,6 +17,7 @@ obj-y += init-mm.o obj-$(CONFIG_BOUNCE) += bounce.o obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o +obj-$(CONFIG_FRONTSWAP) += frontswap.o obj-$(CONFIG_HAS_DMA) += dmapool.o obj-$(CONFIG_HUGETLBFS) += hugetlb.o obj-$(CONFIG_NUMA) += mempolicy.o --- linux-2.6.34-rc5/mm/Kconfig 2010-04-19 17:29:56.000000000 -0600 +++ linux-2.6.34-rc5-frontswap/mm/Kconfig 2010-04-21 09:17:37.000000000 -0600 @@ -287,3 +287,19 @@ config NOMMU_INITIAL_TRIM_EXCESS of 1 says that all excess pages should be trimmed. See Documentation/nommu-mmap.txt for more information. + +config FRONTSWAP + bool "Enable frontswap pseudo-RAM driver to cache swap pages" + default y + help + Frontswap is so named because it can be thought of as the opposite of + a "backing" store for a swap device. The storage is assumed to be + a synchronous concurrency-safe page-oriented pseudo-RAM device (such + as Xen's Transcendent Memory, aka "tmem") which is not directly + accessible or addressable by the kernel and is of unknown (and + possibly time-varying) size. When a pseudo-RAM device is available, + a signficant swap I/O reduction may be achieved. When none is + available, all frontswap calls are reduced to a single pointer- + compare-against-NULL resulting in a negligible performance hit. + + If unsure, say Y to enable frontswap. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/