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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D529C433F5 for ; Mon, 11 Oct 2021 01:09:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46B9D60F6E for ; Mon, 11 Oct 2021 01:09:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233375AbhJKBLg (ORCPT ); Sun, 10 Oct 2021 21:11:36 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:28908 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232586AbhJKBLf (ORCPT ); Sun, 10 Oct 2021 21:11:35 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HSLDz4x22zbn2h; Mon, 11 Oct 2021 09:05:07 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Mon, 11 Oct 2021 09:09:30 +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_CBC_SHA256) id 15.1.2308.8; Mon, 11 Oct 2021 09:09:30 +0800 Message-ID: <6d78633c-8e74-1d84-5f02-90fc56c1a11b@huawei.com> Date: Mon, 11 Oct 2021 09:09:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.1.1 Subject: Re: [PATCH v4 0/3] arm64: support page mapping percpu first chunk allocator Content-Language: en-US To: Andrew Morton CC: , , , , , , , , , , References: <20210910053354.26721-1-wangkefeng.wang@huawei.com> <20211010143622.18f491df5591d039cda8f7b7@linux-foundation.org> From: Kefeng Wang In-Reply-To: <20211010143622.18f491df5591d039cda8f7b7@linux-foundation.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggeme715-chm.china.huawei.com (10.1.199.111) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/10/11 5:36, Andrew Morton wrote: > On Fri, 10 Sep 2021 13:33:51 +0800 Kefeng Wang wrote: > >> Percpu embedded first chunk allocator is the firstly option, but it >> could fails on ARM64, eg, >> "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000" >> "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000" >> "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000" >> >> then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838", >> even the system could not boot successfully. >> >> Let's implement page mapping percpu first chunk allocator as a fallback >> to the embedding allocator to increase the robustness of the system. >> >> Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and KASAN_VMALLOC enabled. > > How serious are these problems in real-world situations? Do people > feel that a -stable backport is needed, or is a 5.16-rc1 merge > sufficient? > . Thanks Andrew. A specific memory layout is required(also with KASAN enabled), we met this issue at qemu and real hardware, due to KASAN enabled, so I think 5.16-rc1 is sufficient.