From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5945C2C81 for ; Fri, 22 Oct 2021 05:38:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=joQSPE1jf42K9iGwtLp9ug4KvVxpkMDtCEtS/1k1vQs=; b=jpz74NF63z9Xx79gxcWJoLwz/A piNaP7v1tEooFSBcu8kxM7mBbUWzsoeD+UW7lVE73ZJdXIJuxYCJuwJ78e6E+6QmPWP/KmL4EeqXS 2slRXyqI/CVBgh8MCxe6+Or75SfRoVW/Jc3zfBEfXmxwpwol+L0R7CHTU9bEfc3GETUBSG4KeZ0ii B77KRbiJ3NS6xTy8bVDD2B/ujpplso5cB9C1Ze6Mai377gQ59FDIb6DJ4Qlid9ICuLCmRbDawEUTE Rcd49rL8fcfyxLPtVCZTzQPPUP2TxjFptZTRfCg3eePEEWSyM6+BRXrDk4Q+c7E8boGbHY1+rVcI6 C3yjGJkw==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdnFg-009lbb-Bd; Fri, 22 Oct 2021 05:38:00 +0000 Date: Thu, 21 Oct 2021 22:38:00 -0700 From: Christoph Hellwig To: "Darrick J. 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> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: 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 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.