From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx157.postini.com [74.125.245.157]) by kanga.kvack.org (Postfix) with SMTP id 148BC6B006E for ; Tue, 21 May 2013 17:06:53 -0400 (EDT) Date: Tue, 21 May 2013 18:06:32 -0300 From: Rafael Aquini Subject: Re: [RFC PATCH 01/02] swap: discard while swapping only if SWAP_FLAG_DISCARD_CLUSTER Message-ID: <20130521210628.GD20178@optiplex.redhat.com> References: <519AC605.4070709@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <519AC605.4070709@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: linux-kernel@vger.kernel.org, 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 Howdy Kosaki-san, Thanks for your time over this one :) On Mon, May 20, 2013 at 08:55:33PM -0400, KOSAKI Motohiro wrote: > (5/20/13 8:04 PM), Rafael Aquini wrote: > > Intruduce a new flag to make page-cluster fine-grained discards while swapping > > conditional, as they can be considered detrimental to some setups. However, > > keep allowing batched discards at sys_swapon() time, when enabled by the > > system administrator. > > > > Signed-off-by: Rafael Aquini > > --- > > include/linux/swap.h | 8 +++++--- > > mm/swapfile.c | 12 ++++++++---- > > 2 files changed, 13 insertions(+), 7 deletions(-) > > > > diff --git a/include/linux/swap.h b/include/linux/swap.h > > index 1701ce4..ab2e742 100644 > > --- a/include/linux/swap.h > > +++ b/include/linux/swap.h > > @@ -19,10 +19,11 @@ struct bio; > > #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ > > #define SWAP_FLAG_PRIO_MASK 0x7fff > > #define SWAP_FLAG_PRIO_SHIFT 0 > > -#define SWAP_FLAG_DISCARD 0x10000 /* discard swap cluster after use */ > > +#define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap areas */ > > +#define SWAP_FLAG_DISCARD_CLUSTER 0x20000 /* discard swap clusters after use */ > > From point of backward compatibility view, 0x10000 should be disable both discarding > when mount and when IO. I think you mean 0x10000 should be enable both here, then. That's a nice catch. I'll try to think a way to accomplish it in a simple fashion. > And, introducing new two flags, enable mount time discard and enable IO time discard. > > IOW, Please consider newer kernel and older swapon(8) conbination. > Other than that, looks good to me. > > -- 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