From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [GIT PATCH] another tranche of SCSI updates for 2.6.26 Date: Mon, 28 Apr 2008 08:13:03 -0400 Message-ID: <1209384784.3367.1.camel@localhost.localdomain> References: <1209320076.3801.26.camel@localhost.localdomain> <20080428013400.GA6245@elte.hu> <1209351113.3801.107.camel@localhost.localdomain> <48157B6A.60307@panasas.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from accolon.hansenpartnership.com ([76.243.235.52]:38716 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765110AbYD1MNJ (ORCPT ); Mon, 28 Apr 2008 08:13:09 -0400 In-Reply-To: <48157B6A.60307@panasas.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Boaz Harrosh Cc: Ingo Molnar , Andrew Morton , Linus Torvalds , linux-scsi , linux-kernel On Mon, 2008-04-28 at 10:23 +0300, Boaz Harrosh wrote: > If we are already on the subject. It looks like we always have at most 1 command in the > free list, so why the free list at all? or am I reading the code wrong? Because list handlers are well understood mechanisms within the kernel. Also because in low memory situations, one command per host is sufficient to guarantee forward progress, but it's not going to be very efficient. Embedded and other low memory environments can increase the size of the free list to improve their I/O path. James