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=-15.3 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,URIBL_BLOCKED, USER_AGENT_SANE_1 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 457FAC432BE for ; Mon, 2 Aug 2021 02:39:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 642E1610A2 for ; Mon, 2 Aug 2021 02:39:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 642E1610A2 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 D366A6B0033; Sun, 1 Aug 2021 22:39:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CE69E8D0001; Sun, 1 Aug 2021 22:39:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BFC266B005D; Sun, 1 Aug 2021 22:39:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0156.hostedemail.com [216.40.44.156]) by kanga.kvack.org (Postfix) with ESMTP id A52A96B0033 for ; Sun, 1 Aug 2021 22:39:10 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 433D819255 for ; Mon, 2 Aug 2021 02:39:10 +0000 (UTC) X-FDA: 78428583660.01.A38AA13 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf12.hostedemail.com (Postfix) with ESMTP id 0D2D31005592 for ; Mon, 2 Aug 2021 02:39:08 +0000 (UTC) Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GdMYH6z5zz82x6; Mon, 2 Aug 2021 10:35:15 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 2 Aug 2021 10:39:05 +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; Mon, 2 Aug 2021 10:39:04 +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> From: Kefeng Wang Message-ID: <0de87be6-7041-c58b-a01f-3d6e3333c6f0@huawei.com> Date: Mon, 2 Aug 2021 10:39:04 +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: <20210801152311.GB28489@arm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0D2D31005592 Authentication-Results: imf12.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf12.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: 83fnsgh3tnzkzr4ppf1ncmbwkzhhynx9 X-HE-Tag: 1627871948-275734 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 2021/8/1 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_struct= *vm) >> */ >> void __init vm_area_register_early(struct vm_struct *vm, size_t alig= n) >> { >> - static size_t vm_init_off __initdata; >> + unsigned long vm_start =3D VMALLOC_START; >> + struct vm_struct *tmp; >> unsigned long addr; >> =20 >> - 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; >> =20 >> + addr =3D ALIGN(vm_start, align); >> vm->addr =3D (void *)addr; >> =20 >> vm_area_add_early(vm); > Is there a risk of breaking other architectures? It doesn't look like t= o > me but I thought I'd ask. Before this patch, vm_init_off is to record the offset from VMALLOC_START= , but it use VMALLOC_START as start address on the function=20 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=20 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_SIZE= ); arch/x86/xen/p2m.c:=C2=A0=C2=A0=C2=A0=C2=A0 vm_area_register_early(&vm, P= MD_SIZE *=20 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 vm_a= rea_add_early() and vm_area_register_early() when this patchset is merged. so it won't b= reak other architectures. > > 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 the=20 middle is not different. >