From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CBEFC433EF for ; Fri, 21 Jan 2022 07:17:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DA5786B0080; Fri, 21 Jan 2022 02:17:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D54AD6B0081; Fri, 21 Jan 2022 02:17:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C44CD6B0082; Fri, 21 Jan 2022 02:17:38 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay032.a.hostedemail.com [64.99.140.32]) by kanga.kvack.org (Postfix) with ESMTP id B43916B0080 for ; Fri, 21 Jan 2022 02:17:38 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 80D2C8103B for ; Fri, 21 Jan 2022 07:17:38 +0000 (UTC) X-FDA: 79053438996.03.F099942 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf04.hostedemail.com (Postfix) with ESMTP id 1D21440002 for ; Fri, 21 Jan 2022 07:17:37 +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=yFPxDUUe1fppNO0I1fDa7AQSMUJ89zWSqQ4St/CxUW8=; b=re5gJo5P3fM6JbXabIyQgDSFuL 2/c/R1kbmGwM9wnFvcVIbtFV6CPKFG9KTLSuDQkKjGa7WNFhDfqwXK8gLbDqtDaEMLLkSvfF1Rw68 m15Kn9nvJWBn4B4wYwj1beL1ETujNA/HHaYmLvJM1tinQimQSEbY3tHoWaFsZhrCy0q7ReWHsApIq 7FNG6Ycsi2kWOXn0+33z2cwtPVagIqc4tKLK2Q0YpAKyEXB6MkHql2Px/ou3XS9ptRM0ecbOxqpQB qLixJ458q3LMWO/T57T734HDJV6QUdtx8nSwdkI9MtVzW4rRmkebbT/b2TvZFx5kS+5khxoY0iyXY j6+9XE0A==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nAoAu-00E2IP-QD; Fri, 21 Jan 2022 07:17:32 +0000 Date: Thu, 20 Jan 2022 23:17:32 -0800 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Shiyang Ruan , Christoph Hellwig , Dan Williams , Linux Kernel Mailing List , linux-xfs , Linux NVDIMM , Linux MM , linux-fsdevel , david , Jane Chu Subject: Re: [PATCH v9 02/10] dax: Introduce holder for dax_device Message-ID: References: <20220105185626.GE398655@magnolia> <20220105224727.GG398655@magnolia> <20220105235407.GN656707@magnolia> <76f5ed28-2df9-890e-0674-3ef2f18e2c2f@fujitsu.com> <20220121022200.GG13563@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220121022200.GG13563@magnolia> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 1D21440002 X-Stat-Signature: db14bzhwhsszabrqyu7e6inxk4bmtabq Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=re5gJo5P; spf=none (imf04.hostedemail.com: domain of BATV+e38482cd6722563dea4e+6725+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+e38482cd6722563dea4e+6725+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none X-HE-Tag: 1642749457-600984 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jan 20, 2022 at 06:22:00PM -0800, Darrick J. Wong wrote: > Hm, so that means XFS can only support dax+pmem when there aren't > partitions in use? Ew. Yes. Or any sensible DAX usage going forward for that matter. > > > > (2) extent the holder mechanism to cover a rangeo > > I don't think I was around for the part where "hch balked at a notifier > call chain" -- what were the objections there, specifically? I would > hope that pmem problems would be infrequent enough that the locking > contention (or rcu expiration) wouldn't be an issue...? notifiers are a nightmare untype API leading to tons of boilerplate code. Open coding the notification is almost always a better idea.