From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f48.google.com (mail-pa0-f48.google.com [209.85.220.48]) by kanga.kvack.org (Postfix) with ESMTP id 50BE56B0069 for ; Mon, 27 Oct 2014 03:57:17 -0400 (EDT) Received: by mail-pa0-f48.google.com with SMTP id ey11so4972458pad.21 for ; Mon, 27 Oct 2014 00:57:17 -0700 (PDT) Received: from lgeamrelo02.lge.com (lgeamrelo02.lge.com. [156.147.1.126]) by mx.google.com with ESMTP id dw11si9801353pac.228.2014.10.27.00.57.15 for ; Mon, 27 Oct 2014 00:57:16 -0700 (PDT) Date: Mon, 27 Oct 2014 16:58:30 +0900 From: Joonsoo Kim Subject: Re: [RFC 0/4] [RFC] slub: Fastpath optimization (especially for RT) Message-ID: <20141027075830.GF23379@js1304-P5Q-DELUXE> References: <20141022155517.560385718@linux.com> <20141023080942.GA7598@js1304-P5Q-DELUXE> <20141024045630.GD15243@js1304-P5Q-DELUXE> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: akpm@linuxfoundation.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org, Thomas Gleixner , linux-mm@kvack.org, penberg@kernel.org, iamjoonsoo@lge.com On Fri, Oct 24, 2014 at 09:41:49AM -0500, Christoph Lameter wrote: > > I found that you said retrieving tid first is sufficient to do > > things right in old discussion. :) > > Right but the tid can be obtained from a different processor. > > > One other aspect of this patchset is that it reduces the cache footprint > of the alloc and free functions. This typically results in a performance > increase for the allocator. If we can avoid the page_address() and > virt_to_head_page() stuff that is required because we drop the ->page > field in a sufficient number of places then this may be a benefit that > goes beyond the RT and CONFIG_PREEMPT case. Yeah... if we can avoid those function calls, it would be good. But, current struct kmem_cache_cpu occupies just 32 bytes on 64 bits machine, and, that means just 1 cacheline. Reducing size of struct may have no remarkable performance benefit in this case. Thanks. -- 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