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 07E02CA9ED2 for ; Mon, 12 Oct 2026 08:23:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0B5E86B0095; Mon, 12 Oct 2026 04:23:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0675E6B0096; Mon, 12 Oct 2026 04:23:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EBFA56B0098; Mon, 12 Oct 2026 04:23:24 -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 C3FEC6B0095 for ; Mon, 12 Oct 2026 04:23:24 -0400 (EDT) Received: from smtpin04.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 35AEA40A2A for ; Mon, 12 Oct 2026 08:23:23 +0000 (UTC) X-FDA: 85313284686.04.7DE2A66 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf20.hostedemail.com (Postfix) with ESMTP id 5BF4C1C0004 for ; Mon, 12 Oct 2026 08:23:21 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=oUUX9kCk; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf20.hostedemail.com: domain of vbabka@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=vbabka@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1791793401; b=OJt3MxgU9BXaPNJQI4dtktino8JhQm31reHWQLpoJCJrIMwrI6EZKKtFbyCdejz7bf602H 00YfgTW9SzbZYp4C7dMzxZ6QOLHPJUDu31rTaOuTvp2OA1NmUait7ImBrZSvnc4RrJ/vav kYHmFCaATJmdWUiPQXgKSo7WAfhgMgg= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=oUUX9kCk; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf20.hostedemail.com: domain of vbabka@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=vbabka@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1791793401; 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=d9z8HFwQLWdwCptSKIysBAuEW6nHmYa6sNljw2nHjPs=; b=RVo2kVZVPSn/Aomg/4yHZAOMUAAgwIlMTCKMW3A1wx/+S9Y0GG5Am6VZPkCA7yjxW+MO5n lmCfceblYucfsyvKgB4/UEOzgiS98pY6O8Sis39c6zGlbaFR16aF/e+kj/3p/liHjujsHl NJyyP888j0gm8OlZXlP3oao/VHhV+Ug= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 6A24841144; Mon, 12 Oct 2026 08:23:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB70E1F0089B; Mon, 12 Oct 2026 08:23:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791793400; bh=d9z8HFwQLWdwCptSKIysBAuEW6nHmYa6sNljw2nHjPs=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=oUUX9kCkrclnsjWl9hC+hEtT6yLc7og6n6BlGwkV8DjgO22JJg6rnVyWaom+nj7j3 YYnCdBpGcMtXyFgpJpNOcyJN89akeZ4BCXNocgqGs+byyflugG61jpPVcXpAnjPrYE JDb/3KPVyPvkfkMdV2KDzE9BaYIRX8iftpwn4D5GHiqx+bt6h1kpsv5AA7Si8IkzYf 3eipqtxnUubCslBTZ+tAJluv/s02yRliiCYFeOOFQTmksuLz8y+T/jc+x2r5VzsZy4 Zom33FU2DnkA1dRR0qIS05j8drd8GtuabAtwsVIM76IwQ/uMgQZBFFAwxpUWOVLlEg T4q3fX3ALfjow== Message-ID: <5895ceec-df6a-4604-a7b9-8138212d786f@kernel.org> Date: Mon, 12 Oct 2026 10:23:16 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/slub: clamp slab_min_order to MAX_PAGE_ORDER Content-Language: en-US To: Sang-Heon Jeon , Andrew Morton , Harry Yoo Cc: Christoph Lameter , David Rientjes , Hao Li , linux-mm@kvack.org, Roman Gushchin References: <20261011014841.405327-1-ekffu200098@gmail.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: <20261011014841.405327-1-ekffu200098@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 8pwqxq8oipmw4csbdpbi4n88or4ch754 X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 5BF4C1C0004 X-HE-Tag: 1791793401-943005 X-HE-Meta: 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 Gxk8D8Vv cZBUJ+qNxy77DGTA1c8sUrCuu0mzcnIoBAqA96ZfzocK7zZVvtyZKfQtpqEVt3+FFTLT13STn9tQ3NQQcnh0iT4ml3rXCTgO8VheOEPqRtfEdq2zHYd+8tmtM9sY1aoK4y7wmdYaIeDp6CTxqcw/uyCca/4vRoaYg4jN8LfLURPPdN3xT+Y44X35QL4Y0lA5GnPLTzaV8kT5cK+fiayhFkIT6qeD+3JkO3kUlB6XbOzTyGQQg9qtH05jxtnT9HqhbhiQ3xaKwA1Uj7j58daO/k6CHCDk/Gcoo6TpIuuWaUWMn+G8IbzsI/xT4psKyLT9s8/RchFTxPyhEZEAfP8PJ7bbDdOfdZSV1mC+R Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10/11/26 03:48, Sang-Heon Jeon wrote: > setup_slub_max_order() clamps slab_max_order to MAX_PAGE_ORDER, but > setup_slub_min_order() has no such clamp. > > The buddy allocator cannot allocate more than 2^MAX_PAGE_ORDER pages > at once, so slab_min_order above it makes no sense. > > If slab_min_order is set above MAX_PAGE_ORDER, it can even panic at > boot or invoke undefined behavior in order_objects(). > > So clamp slab_min_order to MAX_PAGE_ORDER as well. > > Fixes: 81819f0fc828 ("SLUB core") > Signed-off-by: Sang-Heon Jeon Hi, this is effectively part of my bigger refactor here: https://lore.kernel.org/linux-mm/20260923-slub_tiny_rework-v1-1-a0e66d536eb5@kernel.org/ Thanks, Vlastimil > --- > Changes from v1 [1] > - Change fixes tag to 81819f0fc828 ("SLUB core") > - Remove stable tag > > [1] https://lore.kernel.org/all/20261007163403.1643768-1-ekffu200098@gmail.com/#t > --- > mm/slub.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/slub.c b/mm/slub.c > index 1559cbace469..8400df7c222e 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -8354,6 +8354,8 @@ static int __init setup_slub_min_order(const char *str, const struct kernel_para > if (ret) > return ret; > > + slub_min_order = min_t(unsigned int, slub_min_order, MAX_PAGE_ORDER); > + > if (slub_min_order > slub_max_order) > slub_max_order = slub_min_order; > > > base-commit: d755441b7672c74f29d1241ffdd2b067ecab1ca0