From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 123146B0005 for ; Mon, 1 Feb 2016 09:24:50 -0500 (EST) Received: by mail-wm0-f51.google.com with SMTP id l66so73731370wml.0 for ; Mon, 01 Feb 2016 06:24:50 -0800 (PST) Received: from mail-wm0-f68.google.com (mail-wm0-f68.google.com. [74.125.82.68]) by mx.google.com with ESMTPS id z77si15241524wmz.103.2016.02.01.06.24.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 01 Feb 2016 06:24:48 -0800 (PST) Received: by mail-wm0-f68.google.com with SMTP id l66so9367968wml.2 for ; Mon, 01 Feb 2016 06:24:48 -0800 (PST) Date: Mon, 1 Feb 2016 15:24:46 +0100 From: Michal Hocko Subject: Re: [PATCH 1/2] mm: fix bogus VM_BUG_ON_PAGE() in isolate_lru_page() Message-ID: <20160201142446.GB24008@dhcp22.suse.cz> References: <1454333169-121369-1-git-send-email-kirill.shutemov@linux.intel.com> <1454333169-121369-2-git-send-email-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1454333169-121369-2-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Andrew Morton , Dmitry Vyukov , Vlastimil Babka , David Rientjes , Naoya Horiguchi , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon 01-02-16 16:26:08, Kirill A. Shutemov wrote: > We don't care if there's a tail pages which is not on LRU. We are not > going to isolate them anyway. yes we are not going to isolate them but calling this function on a tail page is wrong in principle, no? PageLRU check is racy outside of lru_lock so what if we are racing here. I know, highly unlikely but not impossible. So I am not really sure this is an improvement. When would we hit this VM_BUG_ON and it wouldn't be a bug or at least suspicious usage? -- Michal Hocko SUSE Labs -- 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