Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758591Ab3EUAF0 (ORCPT ); Mon, 20 May 2013 20:05:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48105 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756487Ab3EUAEr (ORCPT ); Mon, 20 May 2013 20:04:47 -0400 From: Rafael Aquini To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hughd@google.com, shli@kernel.org, kzak@redhat.com, jmoyer@redhat.com, riel@redhat.com, lwoodman@redhat.com, mgorman@suse.de Subject: [RFC PATCH 02/02] swapon: add "cluster-discard" support Date: Mon, 20 May 2013 21:04:25 -0300 Message-Id: <398ace0dd3ca1283372b3aad3fceeee59f6897d7.1369084886.git.aquini@redhat.com> In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5001 Lines: 149 Introduce a new swapon flag/option to support more flexible swap discard setup. The --cluster-discard swapon(8) option can be used by a system admin to flag sys_swapon() to perform page-cluster fine-grained discards. This patch also changes the behaviour of swapon(8) --discard option, that now will only be used to flag sys_swapon() batched discards will be issued at swapon(8) time. Signed-off-by: Rafael Aquini --- sys-utils/swapon.8 | 19 ++++++++++++++++--- sys-utils/swapon.c | 34 ++++++++++++++++++++++++++-------- 2 files changed, 42 insertions(+), 11 deletions(-) diff --git a/sys-utils/swapon.8 b/sys-utils/swapon.8 index 385bf5a..0c8ac69 100644 --- a/sys-utils/swapon.8 +++ b/sys-utils/swapon.8 @@ -112,10 +112,23 @@ All devices marked as ``swap'' in are made available, except for those with the ``noauto'' option. Devices that are already being used as swap are silently skipped. .TP +.TP +.B "\-c, \-\-cluster\-discard" +Swapping will discard clusters of swap pages in between freeing them +and re-writing to them, if the swap device supports that. This option +also implies the +.I \-d, \-\-discard +swapon flag. +The +.I /etc/fstab +mount option +.BI cluster\-discard +may be also used to enable this flag. + +.TP .B "\-d, \-\-discard" -Discard freed swap pages before they are reused, if the swap -device supports the discard or trim operation. This may improve -performance on some Solid State Devices, but often it does not. +Enables swap discards, if the swap device supports that, and performs +a batch discard operation for the swap device at swapon time. The .I /etc/fstab mount option diff --git a/sys-utils/swapon.c b/sys-utils/swapon.c index f1e2433..a71f69e 100644 --- a/sys-utils/swapon.c +++ b/sys-utils/swapon.c @@ -34,7 +34,11 @@ #endif #ifndef SWAP_FLAG_DISCARD -# define SWAP_FLAG_DISCARD 0x10000 /* discard swap cluster after use */ +# define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */ +#endif + +#ifndef SWAP_FLAG_DISCARD_CLUSTER +# define SWAP_FLAG_DISCARD_CLUSTER 0x20000 /* discard swap cluster after use */ #endif #ifndef SWAP_FLAG_PREFER @@ -70,7 +74,7 @@ enum { static int all; static int priority = -1; /* non-prioritized swap by default */ -static int discard; +static int discard = 0; /* don't send swap discards by default */ /* If true, don't complain if the device/file doesn't exist */ static int ifexists; @@ -570,8 +574,11 @@ static int do_swapon(const char *orig_special, int prio, << SWAP_FLAG_PRIO_SHIFT); } #endif - if (fl_discard) + if (fl_discard) { flags |= SWAP_FLAG_DISCARD; + if (fl_discard > 1) + flags |= SWAP_FLAG_DISCARD_CLUSTER; + } status = swapon(special, flags); if (status < 0) @@ -615,8 +622,14 @@ static int swapon_all(void) if (mnt_fs_get_option(fs, "noauto", NULL, NULL) == 0) continue; - if (mnt_fs_get_option(fs, "discard", NULL, NULL) == 0) - dsc = 1; + if (mnt_fs_get_option(fs, "discard", NULL, NULL) == 0) { + if !(dsc) + dsc = 1; + } + if (mnt_fs_get_option(fs, "cluster-discard", NULL, NULL) == 0) { + if (!dsc || dsc == 1) + dsc = 2; + } if (mnt_fs_get_option(fs, "nofail", NULL, NULL) == 0) nofail = 1; if (mnt_fs_get_option(fs, "pri", &p, NULL) == 0 && p) @@ -647,7 +660,8 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out) fputs(USAGE_OPTIONS, out); fputs(_(" -a, --all enable all swaps from /etc/fstab\n" - " -d, --discard discard freed pages before they are reused\n" + " -c, --cluster-discard discard freed pages before they are reused, while swapping\n" + " -d, --discard discard freed pages before they are reused, all at once, at swapon time\n" " -e, --ifexists silently skip devices that do not exist\n" " -f, --fixpgsz reinitialize the swap space if necessary\n" " -p, --priority specify the priority of the swap device\n" @@ -696,6 +710,7 @@ int main(int argc, char *argv[]) static const struct option long_opts[] = { { "priority", 1, 0, 'p' }, + { "cluster-discard", 0, 0, 'c' }, { "discard", 0, 0, 'd' }, { "ifexists", 0, 0, 'e' }, { "summary", 0, 0, 's' }, @@ -719,7 +734,7 @@ int main(int argc, char *argv[]) mnt_init_debug(0); mntcache = mnt_new_cache(); - while ((c = getopt_long(argc, argv, "ahdefp:svVL:U:", + while ((c = getopt_long(argc, argv, "ahcdefp:svVL:U:", long_opts, NULL)) != -1) { switch (c) { case 'a': /* all */ @@ -738,8 +753,11 @@ int main(int argc, char *argv[]) case 'U': add_uuid(optarg); break; + case 'c': + discard += 2; + break; case 'd': - discard = 1; + discard += 1; break; case 'e': /* ifexists */ ifexists = 1; -- 1.7.11.7 -- 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/