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 C7131EB64D9 for ; Fri, 7 Jul 2023 14:39:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 35BF18D0003; Fri, 7 Jul 2023 10:39:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 30BA08D0002; Fri, 7 Jul 2023 10:39:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 15DE18D0003; Fri, 7 Jul 2023 10:39:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 0691A8D0002 for ; Fri, 7 Jul 2023 10:39:03 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id C66C0140DB6 for ; Fri, 7 Jul 2023 14:39:02 +0000 (UTC) X-FDA: 80985072924.12.132B56A Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by imf15.hostedemail.com (Postfix) with ESMTP id 38F33A0007 for ; Fri, 7 Jul 2023 14:38:59 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=JJiwO3bD; dmarc=pass (policy=none) header.from=ibm.com; spf=pass (imf15.hostedemail.com: domain of gerald.schaefer@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=gerald.schaefer@linux.ibm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1688740740; a=rsa-sha256; cv=none; b=wmd6BA13Kk91a7Bx/gYoCuIJmabhlTyB6kuSDFfvXabQa5nFhND6AWFqkouO90c2arVH1J /hV72+nPs9QrRR/BANEzP03/C0zVhlel96Yht1rzgFV8spB5Vphq/8vO4LTD5ZW3rLZgeI BgfAkBvAWl+f2iSt9UdOwHNaSlWk0d0= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=JJiwO3bD; dmarc=pass (policy=none) header.from=ibm.com; spf=pass (imf15.hostedemail.com: domain of gerald.schaefer@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=gerald.schaefer@linux.ibm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688740740; 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=xDHweLfB2jGmEALLzfHomsEO0iNqJHh+OCBfH7P6xK8=; b=XISvqRsEQgP/ea7VXIICPcjrY9OEq37z2mdl0t0JfWY22gKayQLivo4XpLpv9TxLDq0bue j12Qe9c9Tx4IVQwdRE/Bh9Ro6PCvkv0FVzbilNluhGpbxL47N9eXJP87gjyf9oRGnLcKH7 w2jl3pyxn6OIaIwWIy9/u9UvJBf7d/o= Received: from pps.filterd (m0353723.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 367EKoLn002537; Fri, 7 Jul 2023 14:38:18 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=pp1; bh=xDHweLfB2jGmEALLzfHomsEO0iNqJHh+OCBfH7P6xK8=; b=JJiwO3bD6N7eg3IH8SPkBO+4d/XtPlb+o/JWZVlM7CzRU21imiL40tTT7ZrGWc/rcgC8 /ZQawoJzJ/Wi4YLFowBQZTzFSsAioyMZPUQj2/+TzATXsOqAEwPAm/8Er5fao4qLfzKD kRYH5IZgLX1rkVyo5Dnxic2rIqYoORkHY4hH4THeouMwfaTpM9WXeJAc6VddXVoilfaE gfwbTZuv0iejbuxSU1u0BBVFoIAK4bhb+avBCh+DDMSLdfERrKFp1/Onb3Na6Dda/11u xhZI5AYKQfEArH0gbJFiFlEy61E8nbrzVLvMyMHX6afIi6idU/k5hOjVWQR8mRXwhuDJ Xg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rpmcv0h7t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Jul 2023 14:38:17 +0000 Received: from m0353723.ppops.net (m0353723.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 367Ebf4c029017; Fri, 7 Jul 2023 14:37:44 GMT Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rpmcv0ftt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Jul 2023 14:37:44 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 367E0T2h032367; Fri, 7 Jul 2023 14:37:18 GMT Received: from smtprelay04.fra02v.mail.ibm.com ([9.218.2.228]) by ppma06ams.nl.ibm.com (PPS) with ESMTPS id 3rjbde41s0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 07 Jul 2023 14:37:18 +0000 Received: from smtpav03.fra02v.mail.ibm.com (smtpav03.fra02v.mail.ibm.com [10.20.54.102]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 367EbECL36962894 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Jul 2023 14:37:14 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 024662004B; Fri, 7 Jul 2023 14:37:14 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 998F720043; Fri, 7 Jul 2023 14:37:10 +0000 (GMT) Received: from thinkpad-T15 (unknown [9.179.12.113]) by smtpav03.fra02v.mail.ibm.com (Postfix) with SMTP; Fri, 7 Jul 2023 14:37:10 +0000 (GMT) Date: Fri, 7 Jul 2023 16:37:08 +0200 From: Gerald Schaefer To: Hugh Dickins Cc: Alexander Gordeev , Jason Gunthorpe , Andrew Morton , Vasily Gorbik , Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Lorenzo Stoakes , Huang Ying , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , Russell King , "David S. Miller" , Michael Ellerman , "Aneesh Kumar K.V" , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda , Jann Horn , Vishal Moola , Vlastimil Babka , linux-arm-kernel@lists.infradead.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 07/12] s390: add pte_free_defer() for pgtables sharing page Message-ID: <20230707163708.5157e19f@thinkpad-T15> In-Reply-To: <8c6a4a46-2d17-8cfb-50f-f89f1d44973f@google.com> References: <54cb04f-3762-987f-8294-91dafd8ebfb0@google.com> <20230628211624.531cdc58@thinkpad-T15> <20230629175645.7654d0a8@thinkpad-T15> <7bef5695-fa4a-7215-7e9d-d4a83161c7ab@google.com> <8c6a4a46-2d17-8cfb-50f-f89f1d44973f@google.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 9Q6opkkwFp06hBkp91WUs1l0tejkNqki X-Proofpoint-ORIG-GUID: IKcXEBRjrfIrdRwSgUlS8tQG9J7PotRS X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-07_10,2023-07-06_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 spamscore=0 priorityscore=1501 mlxscore=0 clxscore=1015 malwarescore=0 phishscore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2307070134 X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 38F33A0007 X-Stat-Signature: 9eyoxwz1emuh85b3ips3aojzr9iw89og X-HE-Tag: 1688740739-938683 X-HE-Meta: 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 zXHI/25V OjZRZEz7nKXlwPbkTW2jRzZIHYYe1kxgscbd8mzr6Z9Ec/52gPSiXqiMPaNiuMYHymTb7LamHkH8gCqUuQT3TlPBmOiqLnm2NHvaTXS23N+i+vJeJcfVEQCcsxfrsiYoeCweQPwzJiABp42/FkIL6k8g8BeW78km/GARMrsuiVlMm5rITTUKCiyF/Ca9E61TWeAd49jk+Ven1OdwjO4yQzn3ZX9fGHMFbGZxRoxwqeR7l39eaBsjckmwiO/ZT1ZPNbtrMgXD9U261MbtjcDVesLLdOloHj62UJxv3uZgjl246M61MLLEjcOSpY4+YUe0upNiavwjFdE6la5ZSCuiKNGQ1JZGPcAQDBq41IA6IgBe5PXqDAHqeD+cx7ZAxhCDBUTKVvAfzREF6RLPU3jLGtts3sA== 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, 5 Jul 2023 17:52:40 -0700 (PDT) Hugh Dickins wrote: > On Wed, 5 Jul 2023, Alexander Gordeev wrote: > > On Sat, Jul 01, 2023 at 09:32:38PM -0700, Hugh Dickins wrote: > > > On Thu, 29 Jun 2023, Hugh Dickins wrote: > > > > Hi Hugh, > > > > ... > > > > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > > > +void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable) > > > +{ > > > + struct page *page; > > > > If I got your and Claudio conversation right, you were going to add > > here WARN_ON_ONCE() in case of mm_alloc_pgste(mm)? Good point, thanks Alexander for noticing! > > Well, Claudio approved, so I would have put it in, if we had stuck with > that version which had "if (mm_alloc_pgste(mm)) {" in pte_free_defer(); > but once that went away, it became somewhat irrelevant... to me anyway. > > But I don't mind adding it here, in the v3 I'll post when -rc1 is out, > if it might help you guys - there is some point, since pte_free_defer() > is a route which can usefully check for such a case, without confusion > from harmless traffic from immediate frees of just-in-case allocations. > > But don't expect it to catch all such cases (if they exist): another > category of s390 page_table_free()s comes from the PageAnon > zap_deposited_table() in zap_huge_pmd(): those tables might or might > not have been exposed to userspace at some time in the past. Right, after THP collapse, the previously active PTE table would be deposited in this case, and then later freed in zap_deposited_table(). I guess we need to be very careful, if THP was ever enabled for KVM guests. > > I'll add the WARN_ON_ONCE in pte_free_defer() (after checking that > WARN_ON_ONCE is the one we want - I get confused by all the different > flavours of WARN, and have to check the header file each time to be > sure of the syntax and semantics): but be aware that it won't be > checking all potential cases. Thanks, looks good.