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Wong" Cc: Jane Chu , Christoph Hellwig , "david@fromorbit.com" , "dan.j.williams@intel.com" , "vishal.l.verma@intel.com" , "dave.jiang@intel.com" , "agk@redhat.com" , "snitzer@redhat.com" , "dm-devel@redhat.com" , "ira.weiny@intel.com" , "willy@infradead.org" , "vgoyal@redhat.com" , "linux-fsdevel@vger.kernel.org" , "nvdimm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-xfs@vger.kernel.org" Subject: Re: [dm-devel] [PATCH 0/6] dax poison recovery with RWF_RECOVERY_DATA flag Message-ID: References: <20211021001059.438843-1-jane.chu@oracle.com> <20211022015817.GY24307@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211022015817.GY24307@magnolia> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 21, 2021 at 06:58:17PM -0700, Darrick J. Wong wrote: > On Fri, Oct 22, 2021 at 01:37:28AM +0000, Jane Chu wrote: > > On 10/21/2021 4:31 AM, Christoph Hellwig wrote: > > > Looking over the series I have serious doubts that overloading the > > > slow path clear poison operation over the fast path read/write > > > path is such a great idea. > > Why would data recovery after a media error ever be considered a > fast/hot path? Not sure what you're replying to (the text is from me, the mail you are repling to is fom Jane), but my point is that the read/write got path should not be overloaded with data recovery. > A normal read/write to a fsdax file would not pass the > flag, which skips the poison checking with whatever MCE consequences > that has, right? Exactly! > pwritev2(..., RWF_RECOVER_DATA) should be infrequent enough that > carefully stepping around dax_direct_access only has to be faster than > restoring from backup, I hope? Yes. And thus be kept as separate as possible.