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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 CB1E2C4321A for ; Tue, 11 Jun 2019 12:41:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB53B21734 for ; Tue, 11 Jun 2019 12:41:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388330AbfFKMlc (ORCPT ); Tue, 11 Jun 2019 08:41:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34104 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727733AbfFKMlb (ORCPT ); Tue, 11 Jun 2019 08:41:31 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5BCW0NR123936 for ; Tue, 11 Jun 2019 08:41:30 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2t2bkv2umn-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 11 Jun 2019 08:41:29 -0400 Received: from localhost by e06smtp07.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) Tue, 11 Jun 2019 13:41:23 +0100 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5BCfM8E56688832 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Jun 2019 12:41:22 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CC6FB11C052; Tue, 11 Jun 2019 12:41:22 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A368411C050; Tue, 11 Jun 2019 12:41:21 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.204.69]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Tue, 11 Jun 2019 12:41:21 +0000 (GMT) Date: Tue, 11 Jun 2019 15:41:19 +0300 From: Mike Rapoport To: Mark Rutland Cc: Qian Cai , Will Deacon , akpm@linux-foundation.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, mhocko@kernel.org, linux-mm@kvack.org, vdavydov.dev@gmail.com, hannes@cmpxchg.org, cgroups@vger.kernel.org, linux-arm-kernel@lists.infradead.org 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> <20190610114326.GF15979@fuggles.cambridge.arm.com> <1560187575.6132.70.camel@lca.pw> <20190611100348.GB26409@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190611100348.GB26409@lakrids.cambridge.arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19061112-0028-0000-0000-000003794EFF X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19061112-0029-0000-0000-000024393D13 Message-Id: <20190611124118.GA4761@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-11_06:,, 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-1906110086 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 11, 2019 at 11:03:49AM +0100, Mark Rutland wrote: > On Mon, Jun 10, 2019 at 01:26:15PM -0400, Qian Cai wrote: > > On Mon, 2019-06-10 at 12:43 +0100, Will Deacon 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. > > > > > > > > Do we need a separate pgd_alloc_kernel()? > > > > > > So can I take the above for -rc5, or is somebody else working on a different > > > fix to implement pgd_alloc_kernel()? > > > > The offensive commit "arm64: switch to generic version of pte allocation" is not > > yet in the mainline, but only in the Andrew's tree and linux-next, and I doubt > > Andrew will push this out any time sooner given it is broken. > > I'd assumed that Mike would respin these patches to implement and use > pgd_alloc_kernel() (or take gfp flags) and the updated patches would > replace these in akpm's tree. > > Mike, could you confirm what your plan is? I'm happy to review/test > updated patches for arm64. Sorry for the delay, I'm mostly offline these days. I wanted to understand first what is the reason for the failure. I've tried to reproduce it with qemu, but I failed to find a bootable configuration that will have PGD_SIZE != PAGE_SIZE :( Qian Cai, can you share what is your environment and the kernel config? > Thanks, > Mark. > -- Sincerely yours, Mike.