From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id 3186D6B0032 for ; Tue, 28 Apr 2015 18:37:27 -0400 (EDT) Received: by pacyx8 with SMTP id yx8so8810064pac.1 for ; Tue, 28 Apr 2015 15:37:26 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id zd13si36595407pab.169.2015.04.28.15.37.26 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Apr 2015 15:37:26 -0700 (PDT) Date: Tue, 28 Apr 2015 15:37:24 -0700 From: Andrew Morton Subject: Re: [PATCH] compaction: fix isolate_migratepages_block() for THP=n Message-Id: <20150428153724.cbe99bef1e7c2f073755539a@linux-foundation.org> In-Reply-To: <20150428222828.GA6072@node.dhcp.inet.fi> References: <1430134006-215317-1-git-send-email-kirill.shutemov@linux.intel.com> <20150428151420.227e7ac34745e9fe8e9bc145@linux-foundation.org> <20150428222828.GA6072@node.dhcp.inet.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sasha Levin On Wed, 29 Apr 2015 01:28:28 +0300 "Kirill A. Shutemov" wrote: > On Tue, Apr 28, 2015 at 03:14:20PM -0700, Andrew Morton wrote: > > On Mon, 27 Apr 2015 14:26:46 +0300 "Kirill A. Shutemov" wrote: > > > > > PageTrans* helpers are always-false if THP is disabled compile-time. > > > It means the fucntion will fail to detect hugetlb pages in this case. > > > > > > Let's use PageCompound() instead. With small tweak to how we calculate > > > next low_pfn it will make function ready to see tail pages. > > > > > > > > So this patch has no runtime effects at present? It is preparation for > > something else? > > I wrote this to fix bug I originally attributed to refcounting patchset, > but Sasha triggered the same bug on -next without the patchset applied: > > http://lkml.kernel.org/g/553EB993.7030401@oracle.com Well why the heck didn't the changelog tell us this?!?!? > Now I think it's related to changing of PageLRU() behaviour on tail page > by my page flags patchset. So this patch is a bugfix against one of page-flags-trivial-cleanup-for-pagetrans-helpers.patch page-flags-introduce-page-flags-policies-wrt-compound-pages.patch page-flags-define-pg_locked-behavior-on-compound-pages.patch page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch page-flags-define-behavior-slb-related-flags-on-compound-pages.patch page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch page-flags-define-pg_reserved-behavior-on-compound-pages.patch page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch page-flags-define-pg_swapcache-behavior-on-compound-pages.patch page-flags-define-pg_mlocked-behavior-on-compound-pages.patch page-flags-define-pg_uncached-behavior-on-compound-pages.patch page-flags-define-pg_uptodate-behavior-on-compound-pages.patch page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch mm-sanitize-page-mapping-for-tail-pages.patch include-linux-page-flagsh-rename-macros-to-avoid-collisions.patch Which one was the faulty patch? > PageLRU() on tail pages now reports true if > head page is on LRU. It means no we can go futher insede > isolate_migratepages_block() with tail page. -- 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