From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f181.google.com (mail-qc0-f181.google.com [209.85.216.181]) by kanga.kvack.org (Postfix) with ESMTP id D83FE6B0032 for ; Thu, 15 Jan 2015 22:58:01 -0500 (EST) Received: by mail-qc0-f181.google.com with SMTP id l6so6773607qcy.12 for ; Thu, 15 Jan 2015 19:58:01 -0800 (PST) Received: from resqmta-ch2-09v.sys.comcast.net (resqmta-ch2-09v.sys.comcast.net. [2001:558:fe21:29:69:252:207:41]) by mx.google.com with ESMTPS id le8si4636282qcb.11.2015.01.15.19.58.00 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Thu, 15 Jan 2015 19:58:00 -0800 (PST) Date: Thu, 15 Jan 2015 21:57:58 -0600 (CST) From: Christoph Lameter Subject: Re: [PATCH v2 1/2] mm/slub: optimize alloc/free fastpath by removing preemption on/off In-Reply-To: <20150115225130.00c0c99a@grimm.local.home> Message-ID: References: <1421307633-24045-1-git-send-email-iamjoonsoo.kim@lge.com> <20150115171634.685237a4.akpm@linux-foundation.org> <20150115203045.00e9fb73@grimm.local.home> <20150115225130.00c0c99a@grimm.local.home> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Steven Rostedt Cc: Andrew Morton , Joonsoo Kim , Pekka Enberg , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jesper Dangaard Brouer , Thomas Gleixner , Peter Zijlstra > I get: > > mov %gs:0x18(%rax),%rdx > > Looks to me that %gs is used. %gs is used as a segment prefix. That does not add significant cycles. Retrieving the content of %gs and loading it into another register would be expensive in terms of cpu cycles. -- 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