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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F12ADFCC051 for ; Fri, 6 Mar 2026 18:01:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1FBF46B0088; Fri, 6 Mar 2026 13:01:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A9B16B00A7; Fri, 6 Mar 2026 13:01:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0AC526B00A8; Fri, 6 Mar 2026 13:01:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id EB87F6B0088 for ; Fri, 6 Mar 2026 13:00:59 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 96B1259DC6 for ; Fri, 6 Mar 2026 18:00:59 +0000 (UTC) X-FDA: 84516404238.27.BCFB9C3 Received: from relay.hostedemail.com (unirelay06 [10.200.18.69]) by imf08.hostedemail.com (Postfix) with ESMTP id C398E16001B for ; Fri, 6 Mar 2026 18:00:57 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772820057; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Q8ZBfG0sGTE9QlDrlHCSXPcKk7XAlqaSY7GhvFEaFms=; b=6RT2PGL//baPnrNTSTybMGoTfxJ6R0xGgMsbwppwvOGIjRFR90HdcD86Gk41Pp4Rxuv6zJ YDX/3xNRSFH8vhM/4g8xvdQNTIHMRo71Xged+9odTluiOk75eAekpLBD1yJnGskQINp10z rZpkcAVOpBHdJNGMUYj9b75Q7WrlXOY= ARC-Authentication-Results: i=1; imf08.hostedemail.com; none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772820057; a=rsa-sha256; cv=none; b=uykIrV5jiL+5klRqXSHckf/vRdXKBVC+33YbV+KpvZbaLvjekOjHuZjk1HbJHd9saa24o4 lAL9BqKSB+m9JJGq33jMnopHBF5v/1e4bMpNEG+mxnVDh7zQvSgyD8Yuev4HDBhJ8+RwPw kUfGwmljsgV/1D1PLDo8Psxz14B3FFM= Received: from omf11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 837631B85AE; Fri, 6 Mar 2026 18:00:55 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf11.hostedemail.com (Postfix) with ESMTPA id 048F22002F; Fri, 6 Mar 2026 18:00:51 +0000 (UTC) Date: Fri, 6 Mar 2026 13:00:52 -0500 From: Steven Rostedt To: Andrew Morton Cc: Dmitry Ilvokhin , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, Peter Zijlstra Subject: Re: [PATCH 1/8] mm: use zone lock guard in reserve_highatomic_pageblock() Message-ID: <20260306130052.7da8eab3@gandalf.local.home> In-Reply-To: <20260306095336.a79fcc869a7f6d2b2e97501b@linux-foundation.org> References: <20260306095336.a79fcc869a7f6d2b2e97501b@linux-foundation.org> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1/6Ow7aF6DmQhdrW9kJih2ck9+OIyCBH/U= X-HE-Meta: U2FsdGVkX1+PCmMBt+lClgi6UsFpx96YSReA/s0JN4Fg9contLIxr2iGTktY9FD2H68DBV2ce4rR1eDF453v/D4BqPnYbBmgcbAAcqONfI9XKJ0aQ+AEZYEg/fgJkb886L3MfEqbUO/SO0gCsqukCvlRh+GqR6mgrhqS/wNVBF4AIopBFgu9itqpy8C236rhTyL7WYJuaVNmHsl3n5mMwJ3kQ3kZPjZGdSkzrY7MvcfOUL8jikJpao9sBW8cJEMnLBd0vsoViWDcrZQjSnmo1D5/Jd2yOp1lpj6Nd2gckQKQnJt9LbXr1w8VkY/tc8Ta330P/qc2uKmE0jN0krbrQwgZYSH3KUtHHDOWpflUOB6hu++YFbg1he7OjW9WNg9njSrH6es4ThqGFYLIB8XeAPMF/IKSpQxLrK9OgJdl76k3yf4KohOdqvH1beBGSize X-Rspam-User: X-HE-Tag-Orig: 1772820051-753140 X-Rspamd-Queue-Id: C398E16001B X-Rspamd-Server: rspam08 X-Stat-Signature: myjygjb5g1ih1eezpiay44u1oo6pdfkc X-HE-Tag: 1772820057-388874 X-HE-Meta: U2FsdGVkX19WHiqHT5bFKb6vce1YIqripyca/Iqm1EGZ/tXk2G+d+GzFOwBBuAz2iefhNw/+WEMXNPTNxoD/cARemNgtiycSzjnaZsrywe3z70ng3uSm7Ov+2ONOUTyC36YQW3SAqsmDea+fhjWB/OvAzOH3MIQZXSgWemtoQMATw4zboE88Vv5d/CTzuglNT2IycezMLph+/8oQ/WCh06ghIhMQzYDjK6JhBPoe4OZR8gI+fW6QG+GP7oSeLqkl/2lwveqH/lgMlSLetJCelC6u7GLSWRCWhgrm7HIbm3aQsk2vtc8nnM8Tc/KI66+XdCx6JeB766D2PWkkddUp2VAU3R8eSFiAutyVQl6ExV9ydWRvXcJ6lzn0A7qsOWlWehKvMLZg+o6Pqe7P9alsZtS5CfL8jTEGCYIe9J4FETOQkGdHVQ8e924t2ZyhlIDuwtepdLgRDnyIJNtuSKmoO18Kt5CAzYW27Dlf4QhzDazyXN4Z6Jk5Ifn55KU8gpZdZRu6p0EzpP/Q6bfkD1AqGbREDr4fnkXjO99VukCwN/uOseN58nSgu0wAhDj4+HjbhqY7+w+F22zxnovGy3hgZin2d0cxhtVbW2I0v00kSSR7qOqai0BDL5GBFD4s3F3KLDlSyGTjO7Kpo1F9Vt3knLbSYd73kbW1oNOKxA8KchmoLOSLKO2IT5VGXVPKUh3FlK81M0ohf1566XXcGhXSLEVv9se641MevRo6n7ZtTZqQdZH8TS0QiQONgzm9Ajy754PqUu5pSXT355yIZwGsOjDNYTlQdAf4Edm3GeGGRtwBKNTHe8rVP/FB3aG/Oeg+E+KboiTGuIys/4rzhqVOITGYngD/MN+P681fh9In/1qymrngzWte95UwI6l6ngWHdlBKJ+TCIrZW8sRVP9s3E0RKm57FKrwparIQj0wUqmPJ1C5Bx+fhm1/31ByzZkPRcFNnv2FQibnowy4XeDR akuP6pgl mhJcd49H6/Ql1KlcyClMHZvUFiMCOysRp0sTTbEureo7MHxO9QXn4G34EeJAWK9vk/am8prmsnjK8RjbFL/l5DfJEz8/nmKjPsz4Y Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: [ Adding Peter ] On Fri, 6 Mar 2026 09:53:36 -0800 Andrew Morton wrote: > On Fri, 6 Mar 2026 16:05:35 +0000 Dmitry Ilvokhin wrote: > > > Use the newly introduced zone_lock_irqsave lock guard in > > reserve_highatomic_pageblock() to replace the explicit lock/unlock and > > goto out_unlock pattern with automatic scope-based cleanup. > > > > ... > > > > - zone_lock_irqsave(zone, flags); > > + guard(zone_lock_irqsave)(zone); > > guard() is cute, but this patch adds a little overhead - defconfig > page_alloc.o text increases by 32 bytes, presumably all in > reserve_highatomic_pageblock(). More instructions, larger cache > footprint. > > So we're adding a little overhead to every user's Linux machine for all > time. In return for which the developers get a little convenience and > maintainability. I think maintainability is of importance. Is there any measurable slowdown? Or are we only worried about the text size increase? > > Is it worth it? This is being done all over the kernel. Perhaps we should look at ways to make the generic infrastructure more performant? -- Steve