From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 568DA60021B for ; Sun, 27 Dec 2009 20:22:14 -0500 (EST) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id nBS1MBsG029208 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Mon, 28 Dec 2009 10:22:11 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 03F582B6A41 for ; Mon, 28 Dec 2009 10:22:11 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id BDB1C45DE4C for ; Mon, 28 Dec 2009 10:22:10 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id A0DD91DB8045 for ; Mon, 28 Dec 2009 10:22:10 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 53EE11DB8041 for ; Mon, 28 Dec 2009 10:22:10 +0900 (JST) Date: Mon, 28 Dec 2009 10:19:02 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC PATCH] asynchronous page fault. Message-Id: <20091228101902.4a7feac1.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20091228093606.9f2e666c.kamezawa.hiroyu@jp.fujitsu.com> References: <20091225105140.263180e8.kamezawa.hiroyu@jp.fujitsu.com> <1261915391.15854.31.camel@laptop> <20091228093606.9f2e666c.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Peter Zijlstra , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "minchan.kim@gmail.com" , cl@linux-foundation.org List-ID: On Mon, 28 Dec 2009 09:36:06 +0900 KAMEZAWA Hiroyuki wrote: > == one vma == > # Samples: 1338964273489 > # > # Overhead Command Shared Object Symbol > # ........ ............... ........................ ...... > # > 26.90% multi-fault-all [kernel] [k] clear_page_c > | > --- clear_page_c > __alloc_pages_nodemask > handle_mm_fault > do_page_fault > page_fault > 0x400940 > | > --100.00%-- (nil) > > 20.65% multi-fault-all [kernel] [k] _raw_spin_lock > | > --- _raw_spin_lock > | > |--85.07%-- free_pcppages_bulk > | free_hot_cold_page > > .... > 3.94% multi-fault-all [kernel] [k] find_vma_speculative > | > --- find_vma_speculative > | > |--99.40%-- do_page_fault > | page_fault > | 0x400940 > | | > | --100.00%-- (nil) > | > --0.60%-- page_fault > 0x400940 > | > --100.00%-- (nil) > == > A small modification for avoiding atomic_add_unless() makes following score. (used atomic_inc()->atomic_read() instead of that.) == 2.55% multi-fault-all [kernel] [k] vma_put | --- vma_put | |--98.87%-- do_page_fault | page_fault | 0x400940 | (nil) | --1.13%-- page_fault 0x400940 (nil) 0.65% multi-fault-all [kernel] [k] find_vma_speculative | --- find_vma_speculative | |--95.55%-- do_page_fault | page_fault | 0x400940 | | | --100.00%-- (nil) | --4.45%-- page_fault 0x400940 (nil) == Hmm...maybe worth to consider some. I hope something good pops up to me after new year vacation. Regards, -Kame -- 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