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=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 57A98C4338F for ; Thu, 5 Aug 2021 12:46:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9ECB6601FC for ; Thu, 5 Aug 2021 12:46:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 9ECB6601FC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id E9ABF6B006C; Thu, 5 Aug 2021 08:46:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E4B2B6B0071; Thu, 5 Aug 2021 08:46:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D39DD6B0072; Thu, 5 Aug 2021 08:46:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0034.hostedemail.com [216.40.44.34]) by kanga.kvack.org (Postfix) with ESMTP id B9CB26B006C for ; Thu, 5 Aug 2021 08:46:27 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 64D2C8249980 for ; Thu, 5 Aug 2021 12:46:27 +0000 (UTC) X-FDA: 78441000414.19.1295C4E Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf03.hostedemail.com (Postfix) with ESMTP id 402103002248 for ; Thu, 5 Aug 2021 12:46:26 +0000 (UTC) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GgStv3bbkzcl9Q; Thu, 5 Aug 2021 20:42:47 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 5 Aug 2021 20:46:22 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 5 Aug 2021 20:46:21 +0800 Subject: Re: [PATCH v2 1/3] vmalloc: Choose a better start address in vm_area_register_early() To: Catalin Marinas CC: Will Deacon , Andrey Ryabinin , Andrey Konovalov , Dmitry Vyukov , , , , References: <20210720025105.103680-1-wangkefeng.wang@huawei.com> <20210720025105.103680-2-wangkefeng.wang@huawei.com> <20210801152311.GB28489@arm.com> <0de87be6-7041-c58b-a01f-3d6e3333c6f0@huawei.com> <20210804111402.GB4857@arm.com> From: Kefeng Wang Message-ID: Date: Thu, 5 Aug 2021 20:46:20 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20210804111402.GB4857@arm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 402103002248 Authentication-Results: imf03.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf03.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com X-Stat-Signature: urgi35aizcfkmq6kkajnrhudakyp1sbx X-HE-Tag: 1628167586-332653 Content-Transfer-Encoding: quoted-printable 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 2021/8/4 19:14, Catalin Marinas wrote: > On Mon, Aug 02, 2021 at 10:39:04AM +0800, Kefeng Wang wrote: >> On 2021/8/1 23:23, Catalin Marinas wrote: >>> On Tue, Jul 20, 2021 at 10:51:03AM +0800, Kefeng Wang wrote: >>>> There are some fixed locations in the vmalloc area be reserved >>>> in ARM(see iotable_init()) and ARM64(see map_kernel()), but for >>>> pcpu_page_first_chunk(), it calls vm_area_register_early() and >>>> choose VMALLOC_START as the start address of vmap area which >>>> could be conflicted with above address, then could trigger a >>>> BUG_ON in vm_area_add_early(). >>>> >>>> Let's choose the end of existing address range in vmlist as the >>>> start address instead of VMALLOC_START to avoid the BUG_ON. >>>> >>>> Signed-off-by: Kefeng Wang >>>> --- >>>> mm/vmalloc.c | 8 +++++--- >>>> 1 file changed, 5 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >>>> index d5cd52805149..a98cf97f032f 100644 >>>> --- a/mm/vmalloc.c >>>> +++ b/mm/vmalloc.c >>>> @@ -2238,12 +2238,14 @@ void __init vm_area_add_early(struct vm_stru= ct *vm) >>>> */ >>>> void __init vm_area_register_early(struct vm_struct *vm, size_t a= lign) >>>> { >>>> - static size_t vm_init_off __initdata; >>>> + unsigned long vm_start =3D VMALLOC_START; >>>> + struct vm_struct *tmp; >>>> unsigned long addr; >>>> - addr =3D ALIGN(VMALLOC_START + vm_init_off, align); >>>> - vm_init_off =3D PFN_ALIGN(addr + vm->size) - VMALLOC_START; >>>> + for (tmp =3D vmlist; tmp; tmp =3D tmp->next) >>>> + vm_start =3D (unsigned long)tmp->addr + tmp->size; >>>> + addr =3D ALIGN(vm_start, align); >>>> vm->addr =3D (void *)addr; >>>> vm_area_add_early(vm); >>> Is there a risk of breaking other architectures? It doesn't look like= to >>> me but I thought I'd ask. >> Before this patch, vm_init_off is to record the offset from VMALLOC_ST= ART, >> >> but it use VMALLOC_START as start address on the function >> vm_area_register_early() >> >> called firstly,=C2=A0 this will cause the BUG_ON. >> >> With this patch, the most important change is that we choose the start >> address via >> >> dynamic calculate the 'start' address by traversing the list. >> >> [wkf@localhost linux-next]$ git grep vm_area_register_early >> arch/alpha/mm/init.c: vm_area_register_early(&console_remap_vm, PAGE_S= IZE); >> arch/x86/xen/p2m.c:=C2=A0=C2=A0=C2=A0=C2=A0 vm_area_register_early(&vm= , PMD_SIZE * >> PMDS_PER_MID_PAGE); >> mm/percpu.c:=C2=A0=C2=A0=C2=A0 vm_area_register_early(&vm, PAGE_SIZE); >> [wkf@localhost linux-next]$ git grep vm_area_add_early >> arch/arm/mm/ioremap.c:=C2=A0 vm_area_add_early(vm); >> arch/arm64/mm/mmu.c:=C2=A0=C2=A0=C2=A0 vm_area_add_early(vma); >> >> x86/alpha won't call vm_area_add_early(), only arm64 could call both v= m_area_add_early() >> and vm_area_register_early() when this patchset is merged. so it won'= t break other architectures. > Thanks for checking. > >>> Also, instead of always picking the end, could we search for a range >>> that fits? >> We only need a space in vmalloc range,=C2=A0 using end or a range in t= he middle >> is not different. > I was thinking of making it more future-proof in case one registers a > vm area towards the end of the range. It's fairly easy to pick a range > in the middle now that you are adding a list traversal. ok,=C2=A0 will chose a suitable hole in the vmalloc range. >