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 X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E48BC28CC5 for ; Wed, 5 Jun 2019 21:34:07 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0C12B20717 for ; Wed, 5 Jun 2019 21:34:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kXGm/iaT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C12B20717 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Message-Id:In-Reply-To:MIME-Version: References:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=lMSlhhKNwXCEWBa6PTluEeZglGRKS8KtApQKY1XGiBQ=; b=kXGm/iaTZmfG2+ Cd8r35cpMmTUBYrEaNhbuZx8/y0grUUIyqrK8LTu2mhZb4O8UTcC63X+9wFvPcT73gxZdkCJjBd2E scOblQZvQXrjYmbci7ZzKDu7uTgYDeWox0EoyKF8FHtI648aWMvuAioVp4K3uq+DWd/+fgR42uywc QRGd0JowgQsD91fcYtEueAh2Mz67gKJ71pAZckRzn5FqYS4T3/X6bWoI4fQof39l5Z2wSPYxeBsor ctMcNJjPvy+HWfzK809fjCi1Tr+oqeC3z4Cqo6tVLp5Pv14SLMWEZ1DMK6jyMAVFFuUb6EBcf5PyX 5ovCyaTdNYTt6jzL2E/w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hYdXn-00047W-DL; Wed, 05 Jun 2019 21:34:03 +0000 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5] helo=mx0a-001b2d01.pphosted.com) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hYdXi-00045y-Fj for linux-arm-kernel@lists.infradead.org; Wed, 05 Jun 2019 21:34:00 +0000 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x55LWXxY185896 for ; Wed, 5 Jun 2019 17:33:52 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0b-001b2d01.pphosted.com with ESMTP id 2sxkuh52sd-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 05 Jun 2019 17:33:52 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 5 Jun 2019 22:33:46 +0100 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x55LXjbm54984766 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 5 Jun 2019 21:33:45 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ABD83A405F; Wed, 5 Jun 2019 21:33:45 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 80203A4054; Wed, 5 Jun 2019 21:33:44 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.207.19]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Wed, 5 Jun 2019 21:33:44 +0000 (GMT) Date: Thu, 6 Jun 2019 00:33:42 +0300 From: Mike Rapoport To: Mark Rutland Subject: Re: [PATCH -next] arm64/mm: fix a bogus GFP flag in pgd_alloc() References: <1559656836-24940-1-git-send-email-cai@lca.pw> <20190604142338.GC24467@lakrids.cambridge.arm.com> <20190604143020.GD24467@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190604143020.GD24467@lakrids.cambridge.arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19060521-0020-0000-0000-000003469105 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19060521-0021-0000-0000-00002199A1F4 Message-Id: <20190605213342.GA7023@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-05_13:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=60 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906050136 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190605_143358_644020_A1077E50 X-CRM114-Status: GOOD ( 31.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, mhocko@kernel.org, linux-mm@kvack.org, Qian Cai , vdavydov.dev@gmail.com, hannes@cmpxchg.org, cgroups@vger.kernel.org, akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 04, 2019 at 03:30:20PM +0100, Mark Rutland wrote: > On Tue, Jun 04, 2019 at 03:23:38PM +0100, Mark Rutland wrote: > > On Tue, Jun 04, 2019 at 10:00:36AM -0400, Qian Cai wrote: > > > The commit "arm64: switch to generic version of pte allocation" > > > introduced endless failures during boot like, > > > > > > kobject_add_internal failed for pgd_cache(285:chronyd.service) (error: > > > -2 parent: cgroup) > > > > > > It turns out __GFP_ACCOUNT is passed to kernel page table allocations > > > and then later memcg finds out those don't belong to any cgroup. > > > > Mike, I understood from [1] that this wasn't expected to be a problem, > > as the accounting should bypass kernel threads. > > > > Was that assumption wrong, or is something different happening here? > > > > > backtrace: > > > kobject_add_internal > > > kobject_init_and_add > > > sysfs_slab_add+0x1a8 > > > __kmem_cache_create > > > create_cache > > > memcg_create_kmem_cache > > > memcg_kmem_cache_create_func > > > process_one_work > > > worker_thread > > > kthread > > > > > > Signed-off-by: Qian Cai > > > --- > > > arch/arm64/mm/pgd.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c > > > index 769516cb6677..53c48f5c8765 100644 > > > --- a/arch/arm64/mm/pgd.c > > > +++ b/arch/arm64/mm/pgd.c > > > @@ -38,7 +38,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm) > > > if (PGD_SIZE == PAGE_SIZE) > > > return (pgd_t *)__get_free_page(gfp); > > > else > > > - return kmem_cache_alloc(pgd_cache, gfp); > > > + return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_KERNEL); > > > > This is used to allocate PGDs for both user and kernel pagetables (e.g. > > for the efi runtime services), so while this may fix the regression, I'm > > not sure it's the right fix. > > I see that since [1], pgd_alloc() was updated to special-case the > init_mm, which is not sufficient for cases like: > > efi_mm.pgd = pgd_alloc(&efi_mm) > > ... which occurs in a kthread. > > So let's have a pgd_alloc_kernel() to make that explicit. I've hit "send" before seeing this one :) Well, to be completely on the safe side an explicit pgd_alloc_kernel() sounds right. Then it won't be subject to future changes in memcg and will always "Do The Right Thing". > Thanks, > Mark. > -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel