From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9A84B299923 for ; Thu, 9 Jul 2026 20:44:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783629849; cv=none; b=IcLWOs6x9c5a5n3DFhWCfU5TgqH13djMJ6gqaLtRgODjS/flIScaqBm2Nm29gZZWf6LguCwtwQLm2O+ybYmngl6u36BaPuJEGdVJirpB/vrrixJrkdC2eKsAaX3sbzg/2ixZCC0xnpN1B/sZ9u5k/YAhLh/n+XBC2AeQfegSOfY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783629849; c=relaxed/simple; bh=DGl4KzYDgo0VrRnn1xVQTGds9zkP5U7gPOaBspAlrnA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=L+6uF4R/9YjhnbKyV9+UYTQkhK8fKKbh7dJ/oharlxN/QDQXXQ3ER+l/3vbI10baVBeP6DBOQ2J+h3T1ezOI1Ten0AF0SVHFqur8P6ZQ4jR78rxjMfin4uNYEegqGSY2tJKASTAa9KuJCbjVKP0NgAdeSDCRvjMqyQe7IXfLAM8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B1A05jVt; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B1A05jVt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F343E1F000E9; Thu, 9 Jul 2026 20:44:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783629848; bh=Et1g9fkjQA21VEy/dQj18Ponx7GtRjq32b06cYFAtns=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=B1A05jVtaixynbNYumfT8ggsXTfGWBvtrRhGqjEBdchzMQFibVoHTncQ4DCEyKToL POKEXbCiDiQ+7OyC7ej5Wgq3m/EEyB5e8YzUxDxZL35MfCjkTSuSVrQbZhJTil8pSs jYM2QVBfcEI0X6pYNKQL269dkujt4P3Cpms5Xmy5jWjp013xaUF2K8x1KdR8DloFWF hcj7cFtkl3HIFp+9puBA42cOLTRo9PQ1XOIddN5w3EdR7IfMUa9jLsCUVno3RRVfrV CDbkjAHC9sxKRkeO0/SKrYGLtA4F7TmqoYbeiRVCwsqX27cACJblXxXX6B5XY1VuNH lsvlx/fEpgW7A== Message-ID: Date: Thu, 9 Jul 2026 22:44:04 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/4] mm: page_alloc: move capture_control to the page allocator Content-Language: en-US To: Johannes Weiner Cc: Andrew Morton , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Zi Yan , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260626182215.1107966-1-hannes@cmpxchg.org> <20260626182215.1107966-4-hannes@cmpxchg.org> 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/9/26 19:45, Johannes Weiner wrote: > On Thu, Jul 02, 2026 at 12:20:48PM +0200, Vlastimil Babka (SUSE) wrote: >> Now my version (only compile tested): > > Ah, now I get it. Thanks. > >> diff --git a/include/linux/compaction.h b/include/linux/compaction.h >> index f29ef0653546..66a2f70e9e01 100644 >> --- a/include/linux/compaction.h >> +++ b/include/linux/compaction.h >> @@ -58,6 +58,7 @@ enum compact_result { >> }; >> >> struct alloc_context; /* in mm/internal.h */ >> +struct capture_control; /* in mm/internal.h */ >> >> /* >> * Number of free order-0 pages that should be available above given watermark >> @@ -92,7 +93,7 @@ extern int fragmentation_index(struct zone *zone, unsigned int order); >> extern enum compact_result try_to_compact_pages(gfp_t gfp_mask, >> unsigned int order, unsigned int alloc_flags, >> const struct alloc_context *ac, enum compact_priority prio, >> - struct page **page); >> + struct capture_control *capc); >> extern void reset_isolation_suitable(pg_data_t *pgdat); >> extern bool compaction_suitable(struct zone *zone, int order, >> unsigned long watermark, int highest_zoneidx); >> diff --git a/mm/compaction.c b/mm/compaction.c >> index b7878e4a2c4b..902573797f99 100644 >> --- a/mm/compaction.c >> +++ b/mm/compaction.c >> @@ -2792,7 +2792,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc) >> static enum compact_result compact_zone_order(struct zone *zone, int order, >> gfp_t gfp_mask, enum compact_priority prio, >> unsigned int alloc_flags, int highest_zoneidx, >> - struct page **capture) >> + struct capture_control *capc) >> { >> enum compact_result ret; >> struct compact_control cc = { >> @@ -2809,36 +2809,8 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, >> .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY), >> .ignore_block_suitable = (prio == MIN_COMPACT_PRIORITY) >> }; >> - struct capture_control capc = { >> - .cc = &cc, >> - .page = NULL, >> - }; >> - >> - /* >> - * Make sure the structs are really initialized before we expose the >> - * capture control, in case we are interrupted and the interrupt handler >> - * frees a page. >> - */ >> - barrier(); >> - WRITE_ONCE(current->capture_control, &capc); >> >> - ret = compact_zone(&cc, &capc); >> - >> - /* >> - * Make sure we hide capture control first before we read the captured >> - * page pointer, otherwise an interrupt could free and capture a page >> - * and we would leak it. >> - */ >> - WRITE_ONCE(current->capture_control, NULL); >> - *capture = READ_ONCE(capc.page); >> - /* >> - * Technically, it is also possible that compaction is skipped but >> - * the page is still captured out of luck(IRQ came and freed the page). >> - * Returning COMPACT_SUCCESS in such cases helps in properly accounting >> - * the COMPACT[STALL|FAIL] when compaction is skipped. >> - */ >> - if (*capture) >> - ret = COMPACT_SUCCESS; >> + ret = compact_zone(&cc, capc); > > &capc, and I switched it to just return compact_zone(&cc, &capc); > > But otherwise it looks clean to me. I'd just take this as-is with your > From: if you don't mind. Can I add your S-O-B? Sure, but I don't remember if I started from scratch or your version. At least add a co-developed-by yourself or something :) Signed-off-by: Vlastimil Babka (SUSE)