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 A6185C43458 for ; Mon, 29 Jun 2026 14:28:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 390566B00D2; Mon, 29 Jun 2026 10:28:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 319B26B00D3; Mon, 29 Jun 2026 10:28:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1E12A6B00D6; Mon, 29 Jun 2026 10:28:39 -0400 (EDT) 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 CE8FE6B00D2 for ; Mon, 29 Jun 2026 10:28:38 -0400 (EDT) Received: from smtpin18.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 3F8801A014C for ; Mon, 29 Jun 2026 14:28:38 +0000 (UTC) X-FDA: 84933181116.18.E3BA4E2 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf17.hostedemail.com (Postfix) with ESMTP id 6CF2D4000D for ; Mon, 29 Jun 2026 14:28:36 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=klYh+h+N; spf=pass (imf17.hostedemail.com: domain of vbabka@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=vbabka@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1782743316; b=6xpgPgQe3/pnjrWN/LcfOSik9RSexMlrD9UFznwcf1s4l6sTiqO0A9P13Zjaj8E+jwv5Og /vhbo2Sy37gvsU4QC5/i7AlrFRKAQNCRfHBxBByvXvREowSdLYcGSSN4TVCWWmz0ARh3zF Eo2b3GPjGisS+YjtlHih5uOevMaSFzc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1782743316; 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:dkim-signature; bh=8JC0C0FVVaFQrsOmwXSu62JfKtEg4PNYqhPkdJ82cpY=; b=tbWmxXj8U3Nk8X2sqIdGrFJ3USj0Ys+FRTj9BABLfi5yrEG2zN1xva1kcAsFDvCKKHqxYb HsVSnAQky9jdx6rxZfTVt4ACBQbjll2NNOsNX1YOTtoywDWJIhY8GhFTIxdlNZsZ9do76B DCA1WINsSHwpR0XtVCUXWmrklMU6baM= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=klYh+h+N; spf=pass (imf17.hostedemail.com: domain of vbabka@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=vbabka@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id C25F46001D; Mon, 29 Jun 2026 14:28:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA1BE1F000E9; Mon, 29 Jun 2026 14:28:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782743315; bh=8JC0C0FVVaFQrsOmwXSu62JfKtEg4PNYqhPkdJ82cpY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=klYh+h+NCjpwB6o0nF2PE9VU7HROot7A/l/tv/vAa5i3AYwqhTAGp0lNFXv5ZnOls /24b2uxy4GIOG146+tDnU4pb6yZrqHKsVaiHla6LTVnjYhwPAoF1pKIIRR7x/wmnyt B9zGe02inWeG4xYGPgW0WbcIhm4zI4adsYmgUCqSs/40q8Xzl59W0RcYqVcPQo2Rvj /8K9mq25xFhAw0q2W3h3tqH9nO4E3ThAajOiOV1OOJHN85LW0i9qNmXpGo7XtTtGYe wHUbLcOD5rU5K1ewfN8O93ocsV+AU+43m//1LLmYPjumQlycrT2mCGcmIfPzSEb6Qj GcykTGdQkOUPA== Message-ID: <220774cb-ba5b-4a12-a649-955c83bfc704@kernel.org> Date: Mon, 29 Jun 2026 16:28:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] mm/compaction: stop recording free page order in page->private Content-Language: en-US To: Zi Yan , Andrew Morton , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , David Hildenbrand , Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Mike Rapoport Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260628-keep-subpage-private-zero-at-free-v1-0-f4ce3930d10f@nvidia.com> <20260628-keep-subpage-private-zero-at-free-v1-1-f4ce3930d10f@nvidia.com> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <20260628-keep-subpage-private-zero-at-free-v1-1-f4ce3930d10f@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6CF2D4000D X-Stat-Signature: c4k68w9epw87ocbb484i3ftkkzb3h8r7 X-HE-Tag: 1782743316-581934 X-HE-Meta: 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 +3ehBWbx L5i6szU7OeYECmlGuZDcsa64saNXjdLy2R0wLXaj0fVcOKR77Wx4e8FoWHifAZjjxe+43WtDHqJJKAETB4DQ0bL2F2v6xTrjBfNY+xCZFiJaOtckA120kTeQJaaONUgBIzJuy0ti2GqV1RgDa1GZxwzcX5BQWRGg5UcbVIduA5kVEf73go9Cjyo6pzcqdqENeuRxCW1SF17s0+Ck7Zt8+B4ha07QLCiGkIUXRSN3I1VyOv+8A1GHJUA4O74DoD1Pwj9H7E7SGPSFOjgU3eRqAw6RPpV5OjFWLkdpX3+OJ0g9DQ+omdju6ukc08w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 6/29/26 04:56, Zi Yan wrote: > Commit 733aea0b3a7bb ("mm/compaction: add support for >0 order folio > memory compaction.") stores isolated free pages in an array indexed by free > page orders, it is no longer needed to store the order in each page's > ->private field. And there is no code using the stored order. Stop doing > that. Ah, great observation. Cool. > It also prepares for an upcoming change that ensures subpage->private is > zero at page free time and the removal of set_page_private(0) from > prep_compound_tail(). In alloc_contig_frozen_range_noprof(), > isolate_freepages_range() is used to grab free pages from buddy allocator > and it leaves the aforementioned page->private set until > either split_free_frozen_pages() or prep_new_page() is called. That > triggers the upcoming subpage->private nonzero check along once > set_page_private(0) is removed from prep_compound_tail(), which is called > via prep_new_page(). I'm not sure it needs to be said here (or in such detail?) > Signed-off-by: Zi Yan Reviewed-by: Vlastimil Babka (SUSE) > --- > mm/compaction.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index b776f35ad020..349838cc6c19 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -644,7 +644,6 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, > isolated = __isolate_free_page(page, order); > if (!isolated) > break; > - set_page_private(page, order); > > nr_scanned += isolated - 1; > total_isolated += isolated; > @@ -1617,7 +1616,6 @@ static void fast_isolate_freepages(struct compact_control *cc) > /* Isolate the page if available */ > if (page) { > if (__isolate_free_page(page, order)) { > - set_page_private(page, order); > nr_isolated = 1 << order; > nr_scanned += nr_isolated - 1; > total_isolated += nr_isolated; > @@ -1846,7 +1844,6 @@ static struct folio *compaction_alloc_noprof(struct folio *src, unsigned long da > size >>= 1; > > list_add(&freepage[size].lru, &cc->freepages[start_order]); > - set_page_private(&freepage[size], start_order); > } > dst = (struct folio *)freepage; > >