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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95ACBC433DF for ; Thu, 25 Jun 2020 20:35:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 436932072E for ; Thu, 25 Jun 2020 20:35:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="AMrFzgXk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 436932072E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A1E696B005D; Thu, 25 Jun 2020 16:35:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9CCE76B0062; Thu, 25 Jun 2020 16:35:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E3BE6B0070; Thu, 25 Jun 2020 16:35:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0222.hostedemail.com [216.40.44.222]) by kanga.kvack.org (Postfix) with ESMTP id 772256B005D for ; Thu, 25 Jun 2020 16:35:04 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 2C94F8248D7C for ; Thu, 25 Jun 2020 20:35:04 +0000 (UTC) X-FDA: 76968888528.28.hand65_131540026e4f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin28.hostedemail.com (Postfix) with ESMTP id DF2EB2506D for ; Thu, 25 Jun 2020 20:35:03 +0000 (UTC) X-HE-Tag: hand65_131540026e4f X-Filterd-Recvd-Size: 2909 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Thu, 25 Jun 2020 20:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=28eoYY2uGIc1DwA6QcApRQG+3fffIKYfjFEy3EC/Dxs=; b=AMrFzgXkDAU0Jk+yRxwizHzv3T dIDsB2abYaN/5WBY9xDm5Tu+LBOnLcxAaW6925hooa0nzJIycKlPZ32RLl24kZESHi9Sho1VRRn6h nKObtZ5wWxOCNdchklkwz77RInazmElcmZk5AahCU+Izn/4NqJW6KEPW6xyFvb7b7WrNN+oijtO6g bI2KH7eCf66Uw23DtnoRJqmfDuY+oW85z5Wg4KNW2YNISFLtOD0xuzpziSjBgJJ7c9L7t4mtV9jTK B/mMv3e50NGZvDQ8q64GlomBn85rEOxtZFrBCWx90//a8VYf5vxUHN5H/u7engQjgSg/Aepl2ju79 c/GfljpA==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1joYa2-0004hi-NK; Thu, 25 Jun 2020 20:34:42 +0000 Date: Thu, 25 Jun 2020 21:34:42 +0100 From: Matthew Wilcox To: "Darrick J. Wong" Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-xfs@vger.kernel.org, dm-devel@redhat.com, Mikulas Patocka , Jens Axboe , NeilBrown , Yafang Shao Subject: Re: [PATCH 0/6] Overhaul memalloc_no* Message-ID: <20200625203442.GG7703@casper.infradead.org> References: <20200625113122.7540-1-willy@infradead.org> <20200625184832.GP7606@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200625184832.GP7606@magnolia> X-Rspamd-Queue-Id: DF2EB2506D X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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, Jun 25, 2020 at 11:48:32AM -0700, Darrick J. Wong wrote: > On Thu, Jun 25, 2020 at 12:31:16PM +0100, Matthew Wilcox (Oracle) wrote: > > I want a memalloc_nowait like we have memalloc_noio and memalloc_nofs > > for an upcoming patch series, and Jens also wants it for non-blocking > > io_uring. It turns out we already have dm-bufio which could benefit > > from memalloc_nowait, so it may as well go into the tree now. > > > > The biggest problem is that we're basically out of PF_ flags, so we need > > to find somewhere else to store the PF_MEMALLOC_NOWAIT flag. It turns > > out the PF_ flags are really supposed to be used for flags which are > > accessed from other tasks, and the MEMALLOC flags are only going to > > be used by this task. So shuffling everything around frees up some PF > > flags and generally makes the world a better place. > > So, uh, how does this intersect with the patch "xfs: reintroduce > PF_FSTRANS for transaction reservation recursion protection" that > re-adds PF_TRANS because uh I guess we lost some subtlety or another at > some point? I don't know. I read that thread, but I couldn't follow the argument.