From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161733AbXDXM2j (ORCPT ); Tue, 24 Apr 2007 08:28:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161740AbXDXM2j (ORCPT ); Tue, 24 Apr 2007 08:28:39 -0400 Received: from rgminet01.oracle.com ([148.87.113.118]:55563 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161733AbXDXM2j (ORCPT ); Tue, 24 Apr 2007 08:28:39 -0400 Date: Tue, 24 Apr 2007 14:27:39 +0200 From: Jens Axboe To: Vasily Tarasov Cc: LKML , OVZDL Subject: Re: [PATCH] cfq: get rid of cfqq hash Message-ID: <20070424122739.GJ3744@kernel.dk> References: <1177415595.191341.7293.nullmailer@me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1177415595.191341.7293.nullmailer@me> X-Brightmail-Tracker: AAAAAQAAAAI= X-Brightmail-Tracker: AAAAAA== X-Whitelist: TRUE X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 24 2007, Vasily Tarasov wrote: > From: Vasily Tarasov > > cfq hash is no more necessary. We always can get cfqq from io context. > cfq_get_io_context_noalloc() function is introduced, because we don't want to > allocate cic on merging and checking may_queue. > In order to identify sync queue we've used hash key = CFQ_KEY_ASYNC. Since hash > is eliminated we need to use other criterion: sync flag for queue is added. > In all places where we dig in rb_tree we're in current context, so no > additional locking is required. > > > Advantages of this patch: no additional memory for hash, no seeking in hash, > code is cleaner. But it is necessary now to seek cic in per-ioc rbtree, but > it is faster: > - most processes work only with few devices > - most systems have only few block devices > - it is a rb-tree Vasily, thanks for doing this, it's a good cleanup. One request, though - care to rebase this against the cfq devel branch? I'm afraid it's nowhere near applying right now. -- Jens Axboe