From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id B743B8D003A for ; Thu, 17 Feb 2011 12:52:47 -0500 (EST) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 070B23EE0B3 for ; Fri, 18 Feb 2011 02:52:35 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id D940845DE52 for ; Fri, 18 Feb 2011 02:52:34 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id BDB5345DE4D for ; Fri, 18 Feb 2011 02:52:34 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id AE7C4EF8006 for ; Fri, 18 Feb 2011 02:52:34 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.249.87.103]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 7AD4FEF8003 for ; Fri, 18 Feb 2011 02:52:34 +0900 (JST) Date: Fri, 18 Feb 2011 02:46:03 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 2/8] mm: Remove i_mmap_mutex lockbreak Message-Id: <20110218024603.2089221d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110217170854.766930171@chello.nl> References: <20110217170520.229881980@chello.nl> <20110217170854.766930171@chello.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Andrea Arcangeli , Avi Kivity , Thomas Gleixner , Rik van Riel , Ingo Molnar , akpm@linux-foundation.org, Linus Torvalds , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Benjamin Herrenschmidt , David Miller , Hugh Dickins , Mel Gorman , Nick Piggin , Paul McKenney , Yanmin Zhang On Thu, 17 Feb 2011 18:05:22 +0100 Peter Zijlstra wrote: > Hugh says: > "The only significant loser, I think, would be page reclaim (when > concurrent with truncation): could spin for a long time waiting for > the i_mmap_mutex it expects would soon be dropped? " > > Counter points: > - cpu contention makes the spin stop (need_resched()) > - zap pages should be freeing pages at a higher rate than reclaim > ever can > - shouldn't hold up reclaim more than lock_page() would > > I think the simplification of the truncate code is definately worth > it. > > Signed-off-by: Peter Zijlstra Maybe I have to improve batched-uncharge in memcg, whose work depends on ZAP_BLOCK_SIZE....but the zap routine seems cleaner. Reviewed-by: KAMEZAWA Hiroyuki -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org