From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by kanga.kvack.org (Postfix) with ESMTP id 784676B0032 for ; Tue, 28 Apr 2015 18:44:47 -0400 (EDT) Received: by widdi4 with SMTP id di4so158339254wid.0 for ; Tue, 28 Apr 2015 15:44:47 -0700 (PDT) Received: from jenni2.inet.fi (mta-out1.inet.fi. [62.71.2.227]) by mx.google.com with ESMTP id g14si40860183wjz.39.2015.04.28.15.44.45 for ; Tue, 28 Apr 2015 15:44:46 -0700 (PDT) Date: Wed, 29 Apr 2015 01:44:42 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH] compaction: fix isolate_migratepages_block() for THP=n Message-ID: <20150428224442.GA6188@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> <20150428153724.cbe99bef1e7c2f073755539a@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150428153724.cbe99bef1e7c2f073755539a@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Kirill A. Shutemov" , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sasha Levin On Tue, Apr 28, 2015 at 03:37:24PM -0700, Andrew Morton wrote: > 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?!?!? Sasha reported bug in -next after I sent the patch. > > > 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 ^^^ this one is fault, I think. > 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 from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- 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