Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932837Ab1CWNBj (ORCPT ); Wed, 23 Mar 2011 09:01:39 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:58075 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932811Ab1CWNBi (ORCPT ); Wed, 23 Mar 2011 09:01:38 -0400 Date: Wed, 23 Mar 2011 09:01:37 -0400 From: Christoph Hellwig To: Jens Axboe Cc: "linux-kernel@vger.kernel.org" Subject: Re: merging discard request in the block layer Message-ID: <20110323130137.GA10455@infradead.org> References: <20110322194755.GA20122@infradead.org> <4D88FE5E.1010204@fusionio.com> <4D890EBD.1090103@fusionio.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D890EBD.1090103@fusionio.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 734 Lines: 20 On Tue, Mar 22, 2011 at 10:03:57PM +0100, Jens Axboe wrote: > > That would seem to indicate a bug in the merging logic instead. > > What kind of max discard size does you device have? If the max discard > size is smaller than the regular request size, this could help. It's a SCSI device, so the max discard size is a lot larger: # cat /sys/block/sda/queue/max_sectors_kb 512 # cat /sys/block/sda/queue/max_hw_sectors_kb 32767 # cat /sys/block/sda/queue/discard_max_bytes 4294966784 -- 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/