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 29FD2ECAAD3 for ; Wed, 14 Sep 2022 20:58:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7763F6B0071; Wed, 14 Sep 2022 16:58:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7244B6B0073; Wed, 14 Sep 2022 16:58:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5EC4A8D0001; Wed, 14 Sep 2022 16:58:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 4C8046B0071 for ; Wed, 14 Sep 2022 16:58:31 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 2385912061C for ; Wed, 14 Sep 2022 20:58:31 +0000 (UTC) X-FDA: 79911904422.19.F61B39D Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf15.hostedemail.com (Postfix) with ESMTP id B334DA00A5 for ; Wed, 14 Sep 2022 20:58:30 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A8882B81CC2; Wed, 14 Sep 2022 20:58:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DC3BC433D6; Wed, 14 Sep 2022 20:58:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1663189107; bh=13Kqr57N7WjSLCxogiNCCLJj2p5+iCJdoNC3K8yMzSg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Akde85+OMf9K7zWrWyB8xjCRDyztlflzLDljpgIRiaNvhG1YuewX3TzsCsos/n0CF FSDkgjnoPrs/wbb6mdVtNpr9V/SIgYlHlSPnP5rKQDodKX5TsEBKejNy96oj2yAlrw 8/yUPR2n+bMbVgfeBxozthIYbqniW3FLwGUj1BG0= Date: Wed, 14 Sep 2022 13:58:25 -0700 From: Andrew Morton To: Mike Kravetz Cc: Doug Berger , Jonathan Corbet , Rob Herring , Krzysztof Kozlowski , Frank Rowand , Muchun Song , Mike Rapoport , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Borislav Petkov , "Paul E. McKenney" , Neeraj Upadhyay , Randy Dunlap , Damien Le Moal , Florian Fainelli , David Hildenbrand , Zi Yan , Oscar Salvador , Hari Bathini , Kees Cook , - , KOSAKI Motohiro , Mel Gorman , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux.dev Subject: Re: [PATCH 02/21] mm/hugetlb: correct max_huge_pages accounting on demote Message-Id: <20220914135825.88814aa1699e93c8a782abc6@linux-foundation.org> In-Reply-To: References: <20220913195508.3511038-1-opendmb@gmail.com> <20220913195508.3511038-3-opendmb@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663189110; 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=QNOK6bg3WNCxMIPSeQHjNvu0ozBqcVbsBe3WZ1KA250=; b=fnFzGwCPoc3/YFHCLzwrt4ZUbeK6ftre5jWNF97wZBn2tLgI5NLk0VDsGQxtjYdilM8aoH q8KtgUWDt3X28e+xBdnSp9BZburcs8HVONupAiZB8wtIQJRxhpuYfjV30nS2Yo8OnYQ+mA vLpiXaUc/AFnrB6L213D+yVuPdk9SjE= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=Akde85+O; dmarc=none; spf=pass (imf15.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663189110; a=rsa-sha256; cv=none; b=T0BunglnZiiSlM25c0+qoKSfr85WwVu6Z9iLiiqUqdNe/fn4JmJuzCcdKx9ozgl3gWk5Ys SHdDyl9Tk6Wk0MmioKsHixjF/PAxF4dLqKcfxoVhNkATNFN/dlTc8tMY6V/e+4NcjTznhr 5pDmx05GWq8E+WeMqxfZoplxn6aYsdQ= Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=Akde85+O; dmarc=none; spf=pass (imf15.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: B334DA00A5 X-Stat-Signature: ydkif8j36ndbg16bbsaxt4qmfmjdqtku X-HE-Tag: 1663189110-756861 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: On Wed, 14 Sep 2022 10:23:05 -0700 Mike Kravetz wrote: > On 09/13/22 12:54, Doug Berger wrote: > > When demoting a hugepage to a smaller order, the number of pages > > added to the target hstate will be the size of the large page > > divided by the size of the smaller page. > > > > Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") > > Signed-off-by: Doug Berger > > --- > > mm/hugetlb.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index e070b8593b37..79949893ac12 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) > > * based on pool changes for the demoted page. > > */ > > h->max_huge_pages--; > > - target_hstate->max_huge_pages += pages_per_huge_page(h); > > + target_hstate->max_huge_pages += pages_per_huge_page(h) / > > + pages_per_huge_page(target_hstate); > > > > return rc; > > } > > This has already been fixed here, > > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/ Neither version tells us the user-visible runtime effects of the change :(