From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 12 May 2016 04:49:48 -0700 From: Christoph Hellwig To: Richard Weinberger Cc: linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, boris.brezillon@free-electrons.com, maxime.ripard@free-electrons.com, david@sigma-star.at, david@fromorbit.com, dedekind1@gmail.com, alex@nextthing.co, akpm@linux-foundation.org, sasha.levin@oracle.com, iamjoonsoo.kim@lge.com, rvaswani@codeaurora.org, tony.luck@intel.com, shailendra.capricorn@gmail.com, kirill.shutemov@linux.intel.com, hch@infradead.org, hughd@google.com, mgorman@techsingularity.net, vbabka@suse.cz Subject: Re: UBIFS and page migration (take 3) Message-ID: <20160512114948.GA25113@infradead.org> References: <1462974823-3168-1-git-send-email-richard@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1462974823-3168-1-git-send-email-richard@nod.at> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Richard, the series looks fine to me, but it fails to address the root cause: that we have an inherently dangerous default for ->migratepage that assumes that file systems are implemented a certain way. I think the series should also grow a third patch to remove the default and just wire it up for the known good file systems, although we'd need some input on what known good is. Any idea what filesystems do get regular testing with code that's using CMA? A good approximation might be those that use the bufer_head based aops from fs/buffer.c