From: Christoph Hellwig Subject: Re: [PATCH] mm: replace FAULT_FLAG_SIZE with parameter to huge_fault Date: Mon, 6 Feb 2017 06:36:48 -0800 Message-ID: <20170206143648.GA461@infradead.org> References: <148615748258.43180.1690152053774975329.stgit@djiang5-desk3.ch.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: mawilcox-0li6OtcxBFHby3iVrkZq2A@public.gmane.org, linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, jack-IBi9RG/b67k@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, vbabka-AlSwsSmVLrQ@public.gmane.org To: Dave Jiang Return-path: Content-Disposition: inline In-Reply-To: <148615748258.43180.1690152053774975329.stgit-Cxk7aZI4ujnJARH06PadV2t3HXsI98Cx0E9HWUfgJXw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org On Fri, Feb 03, 2017 at 02:31:22PM -0700, Dave Jiang wrote: > Since the introduction of FAULT_FLAG_SIZE to the vm_fault flag, it has > been somewhat painful with getting the flags set and removed at the > correct locations. More than one kernel oops was introduced due to > difficulties of getting the placement correctly. Removing the flag > values and introducing an input parameter to huge_fault that indicates > the size of the page entry. This makes the code easier to trace and > should avoid the issues we see with the fault flags where removal of the > flag was necessary in the fallback paths. Why is this not in struct vm_fault? Also can be use this opportunity to fold ->huge_fault into ->fault?