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 9E769C4829A for ; Tue, 13 Feb 2024 21:06:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 157E76B0099; Tue, 13 Feb 2024 16:06:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0E1376B009A; Tue, 13 Feb 2024 16:06:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EC1D16B009B; Tue, 13 Feb 2024 16:06:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id D866E6B0099 for ; Tue, 13 Feb 2024 16:06:07 -0500 (EST) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A44EEA135D for ; Tue, 13 Feb 2024 21:06:07 +0000 (UTC) X-FDA: 81788013174.13.B018334 Received: from mout-p-101.mailbox.org (mout-p-101.mailbox.org [80.241.56.151]) by imf01.hostedemail.com (Postfix) with ESMTP id 3033F4001F for ; Tue, 13 Feb 2024 21:06:03 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=pankajraghav.com header.s=MBO0001 header.b=ZG4QS4o8; dmarc=none; spf=pass (imf01.hostedemail.com: domain of kernel@pankajraghav.com designates 80.241.56.151 as permitted sender) smtp.mailfrom=kernel@pankajraghav.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707858364; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rlGuEk+lrsb7TKIHP84bbBdxjJkSQOe0GzEds4VJ6uo=; b=MlpWdwdMrxWxGbGvkhbnCCEC8emSzzk9h4TWOOFmYQEQ6ZjwsxjyIgpvpsn9hon3MP6LEc IlNQfsmnWzlFAoqWhWE8i3kTEKShin00Cubi7fJ9Cl3zfp4/MFP9T3sE1KeUSNoudS8SA8 eAIqrkB/5ftgsqK9n5A1bfYaC38e5WM= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=pankajraghav.com header.s=MBO0001 header.b=ZG4QS4o8; dmarc=none; spf=pass (imf01.hostedemail.com: domain of kernel@pankajraghav.com designates 80.241.56.151 as permitted sender) smtp.mailfrom=kernel@pankajraghav.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707858364; a=rsa-sha256; cv=none; b=1PmM5iiEgHooj6kl8W0oLVnhONzLef8VTl+1f/Gc17aQQY/dgTqDXZJIllAxsmOzGMyxDU dONpJ4NxYc5MCilcGg719mTQS6Xg5Ui4vJoX54FYLpaAY+2lA9NEysxtiULw5IkyL29ZAC IWkaRjmJSIxSwqBUI55lg75fHAfK/Z8= Received: from smtp1.mailbox.org (smtp1.mailbox.org [10.196.197.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-101.mailbox.org (Postfix) with ESMTPS id 4TZDPy5hp7z9smr; Tue, 13 Feb 2024 22:05:58 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1707858358; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rlGuEk+lrsb7TKIHP84bbBdxjJkSQOe0GzEds4VJ6uo=; b=ZG4QS4o883VynvBzMh26WK5TOHr+yNiz10QE3/MYTdpyJpXlNQqm8MlMY0oqBHmrcxR/U2 gfSusG0OqEUHDp90Y/iktmMcvIgx+9GuKg3P8OnIkbBbRqYxmqNVWUGmQPBpBRo7pEPsbc Sb5QjfDMhZl9fIaTZ+Hzjf+/pfS1LjAo1I5rwJoG+hiMoXlZ6pSsNWnTA9aPQSObgodAZc 9W+bG8TtxtZ7w7jkMVvPfgCf/ESTLeAZeTcG9cKXaFMzmCdY8V1XBUK7bXjvvz/SZt8KyJ wFB462Hdk6dO/xWQLnJgY8R/EtL3P+irS0UR8Nyp/iBAViXjWL92ymaGxC5zzQ== Date: Tue, 13 Feb 2024 22:05:54 +0100 From: "Pankaj Raghav (Samsung)" To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, mcgrof@kernel.org, gost.dev@samsung.com, akpm@linux-foundation.org, kbusch@kernel.org, chandan.babu@oracle.com, p.raghav@samsung.com, linux-kernel@vger.kernel.org, hare@suse.de, willy@infradead.org, linux-mm@kvack.org, david@fromorbit.com Subject: Re: [RFC v2 01/14] fs: Allow fine-grained control of folio sizes Message-ID: References: <20240213093713.1753368-1-kernel@pankajraghav.com> <20240213093713.1753368-2-kernel@pankajraghav.com> <20240213163431.GS6184@frogsfrogsfrogs> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240213163431.GS6184@frogsfrogsfrogs> X-Rspamd-Queue-Id: 3033F4001F X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: grj18g873h5nrgfjwshkzojcujhrnik7 X-HE-Tag: 1707858363-726331 X-HE-Meta: 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 qy1alMFq uLlXv3ItLGwYkIOTaT+ZFJvFUhdXvVfhPq7pzz5PaOTNHxFrg8PwoIHOm98uBi0GNdlwis7eH527DUtfaQ6czI6hViRCbkxn4g7J99BY1Q/2AepvgRntAG5K5H6BgDeMSdEZKDrDCWiTbGZII51CZZV4H9hqX5IJnRzzYRbonhc4D5KBaZoAowRw1Ms0yDikkJ+M11kYa5wOHYr0= 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: List-Subscribe: List-Unsubscribe: On Tue, Feb 13, 2024 at 08:34:31AM -0800, Darrick J. Wong wrote: > On Tue, Feb 13, 2024 at 10:37:00AM +0100, Pankaj Raghav (Samsung) wrote: > > From: "Matthew Wilcox (Oracle)" > > > > Some filesystems want to be able to limit the maximum size of folios, > > and some want to be able to ensure that folios are at least a certain > > size. Add mapping_set_folio_orders() to allow this level of control. > > The max folio order parameter is ignored and it is always set to > > MAX_PAGECACHE_ORDER. > > Why? If MAX_PAGECACHE_ORDER is 8 and I instead pass in max==3, I'm > going to be surprised by my constraint being ignored. Maybe I said that > because I'm not prepared to handle an order-7 folio; or some customer > will have some weird desire to twist this knob to make their workflow > faster. > > --D Maybe I should have been explicit. We are planning to add support for min order in the first round, and we want to add support for max order once the min order support is upstreamed. It was done mainly to reduce the scope and testing of this series. I definitely agree there are usecases for setting the max order. It is also the feedback we got from LPC. So one idea would be not to expose max option until we add the support for max order? So filesystems can only set the min_order with the initial support? > > +static inline void mapping_set_folio_orders(struct address_space *mapping, > > + unsigned int min, unsigned int max) > > +{ > > + if (min == 1) > > + min = 2; > > + if (max < min) > > + max = min; > > + if (max > MAX_PAGECACHE_ORDER) > > + max = MAX_PAGECACHE_ORDER; > > + > > + /* > > + * XXX: max is ignored as only minimum folio order is supported > > + * currently. > > + */ > > + mapping->flags = (mapping->flags & ~AS_FOLIO_ORDER_MASK) | > > + (min << AS_FOLIO_ORDER_MIN) | > > + (MAX_PAGECACHE_ORDER << AS_FOLIO_ORDER_MAX); > > +} > > +