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=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 6D07EC43218 for ; Tue, 11 Jun 2019 13:02:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2D04D20896 for ; Tue, 11 Jun 2019 13:02:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2D04D20896 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 984766B000A; Tue, 11 Jun 2019 09:02:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9352A6B000C; Tue, 11 Jun 2019 09:02:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7FE056B000D; Tue, 11 Jun 2019 09:02:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id 33C086B000A for ; Tue, 11 Jun 2019 09:02:40 -0400 (EDT) Received: by mail-ed1-f70.google.com with SMTP id d27so20643234eda.9 for ; Tue, 11 Jun 2019 06:02:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:message-id:references:mime-version:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=4DMyWe2oS37T3mS0ayCrmcIxFZr5kIKtudbXOZJI9Hk=; b=Wdnsnh+f+x3UHnp3K5gdIDXytp7X78qjJ+HHUlbkrGmimN9G7iMHkoyUxZyExsJBYX iLiGDba6gP/DtQLGNSuYBP6Amz7GIofA/aqAkVX1FYJVZCcoTbYM5EnnPSuXtCNuJNVr MmzVBPyYeNT5Xj6aCnm8Ez1wwRVdQ6VSSHdSj8LAE5o0PAQtNMMak+KLvEWuOc4LsIaF sBKrcAiSBLSlYShCxfM1/Twu3a43VrXoFaHwT8e6O/7bJDy4m2GHRbeJYKe07sJqW4dX /S8Y1DYbdqJ8LfGaw7SF68xJYH6bt0KwZ8IabW/WWM0QyJD2kqLKUbxSem0NX830i0Eg 30BQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com X-Gm-Message-State: APjAAAXn7Z5XE2KjQvZZFr29a9g2VPVWQdqGyief3fvGheFVB7bOFeev 8CC+clYrFKbQvVDDnXHA8LBxcBcz85miDkWTi1wo6bXxMXGmKlNFLzMSXWf1aJrOwGJ5AOvLlKe 40aq6yyVMeMgKtCEvGwkbn1w7GWqVYRj0QC47WUHIT9WOCspuKhkp9uQjwLlOWKFCvQ== X-Received: by 2002:a17:906:5048:: with SMTP id e8mr64812618ejk.91.1560258159719; Tue, 11 Jun 2019 06:02:39 -0700 (PDT) X-Google-Smtp-Source: APXvYqxGXuazBrWFgaFi3bwDP9M/8cxpAVXruIYYAXY6mJc19uohunn2+kn9Xb//5NrT0qfAODti X-Received: by 2002:a17:906:5048:: with SMTP id e8mr64812528ejk.91.1560258158710; Tue, 11 Jun 2019 06:02:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1560258158; cv=none; d=google.com; s=arc-20160816; b=NhdS0aDpVxqasa7sWqHsbmNMvj6B4Ha1HAvJqmF0FEIr358cbfTcBhPBTACAwatuz8 1MtAiw/JU52OJW82PTZxVdVyzvTbhuPDN8GqHOH8Xl2HVIRMF/O2DR3p1r6aVe58JMkn 5pespiTi9PYIdkCZaT7/Ho1c2L99W6jddQtsbexLJWLujij84UmMMZhp1PVXKhn7ixVv BEujT0OxHTzFtEeYnza1aBU7ygWm4N2S1uuJR9eosB/rk40erl0+QMHgU4hKEhH3p5kT x3NixWtDcC/78c8fSVjU+mf4odV7ZkcIvX6LGTO1U0A1qfSVSeKubbSFiOBLSaaahwcY bbMg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-transfer-encoding :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=4DMyWe2oS37T3mS0ayCrmcIxFZr5kIKtudbXOZJI9Hk=; b=yyOUeBURl1kpwIbBylY/m4s4dt6JNsXWIyXRuqU1hYNlvIXdE+HXaSEuhjZzA9vFW5 JC7QiwGNlfK46Z3DBhzLj07VfxC9ChOKbEJSmhyejO+RRkUgciEDUqJkE8ulSqbYfSSc kBnTOue3gVi0H7f5hLgmJKSVPeVkP76ccQ8LeLrE7J3qXImH/+B+cm2x3okPpyggoyh0 3RsEZzIoKTsTMf7TC8MGl1MyDk5ZWxI1TPt65IMGZxSnfTD0QR5MWrfOpAvNSLLY0AnS NHD209Hi90I8bmBgANYl1nbOwHT5zi2D91V2y1QpBVWSDWNMW9XbB+GeW7OzeZNTqIE6 KoFQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com Received: from foss.arm.com (foss.arm.com. [217.140.110.172]) by mx.google.com with ESMTP id q4si3416197ejj.280.2019.06.11.06.02.38 for ; Tue, 11 Jun 2019 06:02:38 -0700 (PDT) Received-SPF: pass (google.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) client-ip=217.140.110.172; Authentication-Results: mx.google.com; spf=pass (google.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9E8EE344; Tue, 11 Jun 2019 06:02:37 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0D24B3F557; Tue, 11 Jun 2019 06:02:35 -0700 (PDT) Date: Tue, 11 Jun 2019 14:02:33 +0100 From: Mark Rutland To: Mike Rapoport 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() Message-ID: <20190611130233.GD29008@lakrids.cambridge.arm.com> 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> <20190611124118.GA4761@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190611124118.GA4761@rapoport-lnx> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) 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 Tue, Jun 11, 2019 at 03:41:19PM +0300, Mike Rapoport wrote: > 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 :( This is the case with 48-bit VA and 64K pages. In that case we have three levels of table, and the PGD is 1/16th of a page, as it only needs to resolve 9 bits of virtual address rather than 13. If you build defconfig + ARM64_64K_PAGES=y, that should be the case: [mark@lakrids:~/src/linux]% usekorg 8.1.0 aarch64-linux-objdump -d arch/arm64/mm/pgd.o arch/arm64/mm/pgd.o: file format elf64-littleaarch64 Disassembly of section .text: 0000000000000000 : 0: a9bf7bfd stp x29, x30, [sp, #-16]! 4: 90000000 adrp x0, 0 8: 5281b801 mov w1, #0xdc0 // #3520 c: 910003fd mov x29, sp 10: f9400000 ldr x0, [x0] 14: 94000000 bl 0 18: a8c17bfd ldp x29, x30, [sp], #16 1c: d65f03c0 ret 0000000000000020 : 20: a9bf7bfd stp x29, x30, [sp, #-16]! 24: 90000000 adrp x0, 0 28: 910003fd mov x29, sp 2c: f9400000 ldr x0, [x0] 30: 94000000 bl 0 34: a8c17bfd ldp x29, x30, [sp], #16 38: d65f03c0 ret Disassembly of section .init.text: 0000000000000000 : 0: a9bf7bfd stp x29, x30, [sp, #-16]! 4: 52804002 mov w2, #0x200 // #512 8: d2800004 mov x4, #0x0 // #0 c: 910003fd mov x29, sp 10: 2a0203e1 mov w1, w2 14: 52a00083 mov w3, #0x40000 // #262144 18: 90000000 adrp x0, 0 1c: 91000000 add x0, x0, #0x0 20: 94000000 bl 0 24: 90000001 adrp x1, 0 28: a8c17bfd ldp x29, x30, [sp], #16 2c: f9000020 str x0, [x1] 30: d65f03c0 ret Thanks, Mark.