From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 8F3E76B0389 for ; Tue, 7 Mar 2017 10:17:52 -0500 (EST) Received: by mail-wr0-f197.google.com with SMTP id l37so1478408wrc.7 for ; Tue, 07 Mar 2017 07:17:52 -0800 (PST) Received: from mail-wm0-x244.google.com (mail-wm0-x244.google.com. [2a00:1450:400c:c09::244]) by mx.google.com with ESMTPS id n110si398229wrb.159.2017.03.07.07.17.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Mar 2017 07:17:51 -0800 (PST) Received: by mail-wm0-x244.google.com with SMTP id n11so1528459wma.0 for ; Tue, 07 Mar 2017 07:17:51 -0800 (PST) Date: Tue, 7 Mar 2017 18:17:47 +0300 From: "Kirill A. Shutemov" Subject: Re: [RFC 05/11] mm: make the try_to_munlock void function Message-ID: <20170307151747.GA2940@node.shutemov.name> References: <1488436765-32350-1-git-send-email-minchan@kernel.org> <1488436765-32350-6-git-send-email-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1488436765-32350-6-git-send-email-minchan@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , kernel-team@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Michal Hocko , Vlastimil Babka , "Kirill A . Shutemov" On Thu, Mar 02, 2017 at 03:39:19PM +0900, Minchan Kim wrote: > try_to_munlock returns SWAP_MLOCK if the one of VMAs mapped > the page has VM_LOCKED flag. In that time, VM set PG_mlocked to > the page if the page is not pte-mapped THP which cannot be > mlocked, either. > > With that, __munlock_isolated_page can use PageMlocked to check > whether try_to_munlock is successful or not without relying on > try_to_munlock's retval. It helps to make ttu/ttuo simple with > upcoming patches. I *think* you're correct, but it took time to wrap my head around. We basically rely on try_to_munlock() never caller for PTE-mapped THP. And we don't at the moment. It worth adding something like VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page); into try_to_munlock(). Otherwise looks good to me. Will free adding my Acked-by once this nit is addressed. -- Kirill A. Shutemov -- 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