From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id ABD0C6B0005 for ; Thu, 16 Jun 2016 19:11:23 -0400 (EDT) Received: by mail-io0-f198.google.com with SMTP id s63so120572352ioi.1 for ; Thu, 16 Jun 2016 16:11:23 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id 69si8437379pfr.155.2016.06.16.16.11.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Jun 2016 16:11:23 -0700 (PDT) Date: Thu, 16 Jun 2016 16:11:21 -0700 From: Andrew Morton Subject: Re: [PATCH 1/3] mm: Don't blindly assign fallback_migrate_page() Message-Id: <20160616161121.35ee5183b9ef9f7b7dcbc815@linux-foundation.org> In-Reply-To: <1466112375-1717-2-git-send-email-richard@nod.at> References: <1466112375-1717-1-git-send-email-richard@nod.at> <1466112375-1717-2-git-send-email-richard@nod.at> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Richard Weinberger Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, hannes@cmpxchg.org, mgorman@techsingularity.net, n-horiguchi@ah.jp.nec.com, mhocko@suse.com, kirill.shutemov@linux.intel.com, hughd@google.com, vbabka@suse.cz, adrian.hunter@intel.com, dedekind1@gmail.com, hch@infradead.org, linux-fsdevel@vger.kernel.org, boris.brezillon@free-electrons.com, maxime.ripard@free-electrons.com, david@sigma-star.at, david@fromorbit.com, alex@nextthing.co, sasha.levin@oracle.com, iamjoonsoo.kim@lge.com, rvaswani@codeaurora.org, tony.luck@intel.com, shailendra.capricorn@gmail.com On Thu, 16 Jun 2016 23:26:13 +0200 Richard Weinberger wrote: > While block oriented filesystems use buffer_migrate_page() > as page migration function other filesystems which don't > implement ->migratepage() will automatically get fallback_migrate_page() > assigned. fallback_migrate_page() is not as generic as is should > be. Page migration is filesystem specific and a one-fits-all function > is hard to achieve. UBIFS leaned this lection the hard way. > It uses various page flags and fallback_migrate_page() does not > handle these flags as UBIFS expected. > > To make sure that no further filesystem will get confused by > fallback_migrate_page() disable the automatic assignment and > allow filesystems to use this function explicitly if it is > really suitable. hm, is there really much point in doing this? I assume it doesn't actually affect any current filesystems? [2/3] is of course OK - please add it to the UBIFS tree. -- 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