From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f179.google.com (mail-ob0-f179.google.com [209.85.214.179]) by kanga.kvack.org (Postfix) with ESMTP id A1BC96B0031 for ; Thu, 19 Dec 2013 00:00:00 -0500 (EST) Received: by mail-ob0-f179.google.com with SMTP id wm4so658319obc.24 for ; Wed, 18 Dec 2013 21:00:00 -0800 (PST) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id ds9si1907811obc.73.2013.12.18.20.59.59 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 18 Dec 2013 20:59:59 -0800 (PST) Message-ID: <52B27D48.9030703@oracle.com> Date: Wed, 18 Dec 2013 23:59:52 -0500 From: Sasha Levin MIME-Version: 1.0 Subject: Re: [PATCH v2] mm/rmap: fix BUG at rmap_walk References: <1387424720-22826-1-git-send-email-liwanp@linux.vnet.ibm.com> <20131219042902.GA27512@hacker.(null)> In-Reply-To: <20131219042902.GA27512@hacker.(null)> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wanpeng Li , Bob Liu Cc: Andrew Morton , Hugh Dickins , Joonsoo Kim , Linux-MM , Linux-Kernel On 12/18/2013 11:29 PM, Wanpeng Li wrote: >> PageLocked is not required by page_referenced_anon() and there is not >> >any assertion before, commit 37f093cdf introduced this extra BUG_ON() > There are two callsites shrink_active_list and page_check_references() > of page_referenced(). shrink_active_list and its callee won't lock anonymous > page, however, page_check_references() is called with anonymous page > lock held in shrink_page_list. So page_check_references case need > specail handling. This explanation seems to be based on current observed behaviour. I think it would be easier if you could point out the actual code in each function that requires a page to be locked, once we have that we don't have to care about what the callers currently do. Thanks, Sasha -- 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