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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A66AEC433EF for ; Fri, 17 Jun 2022 07:39:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380630AbiFQHjO (ORCPT ); Fri, 17 Jun 2022 03:39:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380565AbiFQHjO (ORCPT ); Fri, 17 Jun 2022 03:39:14 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB6E8663F8; Fri, 17 Jun 2022 00:39:12 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4LPW8Q0yF8zhXb1; Fri, 17 Jun 2022 15:37:10 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 17 Jun 2022 15:39:08 +0800 Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 17 Jun 2022 15:39:07 +0800 Subject: Re: [PATCH 1/5] arm64: kdump: Provide default size when crashkernel=Y,low is not specified To: Baoquan He CC: Thomas Gleixner , Ingo Molnar , Borislav Petkov , , "H . Peter Anvin" , Eric Biederman , Rob Herring , Frank Rowand , , Dave Young , Vivek Goyal , , , Catalin Marinas , Will Deacon , , Jonathan Corbet , , Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , "John Donnelly" , Dave Kleikamp References: <20220613080932.663-1-thunder.leizhen@huawei.com> <20220613080932.663-2-thunder.leizhen@huawei.com> <20220617024042.GC234358@MiWiFi-R3L-srv> From: "Leizhen (ThunderTown)" Message-ID: <26bb3d13-fb8b-3e1d-2529-31d34d3c1c1d@huawei.com> Date: Fri, 17 Jun 2022 15:39:06 +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: <20220617024042.GC234358@MiWiFi-R3L-srv> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 2022/6/17 10:40, Baoquan He wrote: > On 06/13/22 at 04:09pm, Zhen Lei wrote: >> To be consistent with the implementation of x86 and improve cross-platform >> user experience. Try to allocate at least 256 MiB low memory automatically >> when crashkernel=Y,low is not specified. > > This should correspond to the case that crashkernel=,high is explicitly > specified, while crashkenrel=,low is omitted. It could be better to > mention these. Okay, I'll update the description in the next version. > > Otherwise, this looks good to me. > >> >> Signed-off-by: Zhen Lei >> --- >> Documentation/admin-guide/kernel-parameters.txt | 8 +------- >> arch/arm64/mm/init.c | 12 +++++++++++- >> 2 files changed, 12 insertions(+), 8 deletions(-) >> >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt >> index 8090130b544b070..61b179232b68001 100644 >> --- a/Documentation/admin-guide/kernel-parameters.txt >> +++ b/Documentation/admin-guide/kernel-parameters.txt >> @@ -843,7 +843,7 @@ >> available. >> It will be ignored if crashkernel=X is specified. >> crashkernel=size[KMG],low >> - [KNL, X86-64] range under 4G. When crashkernel=X,high >> + [KNL, X86-64, ARM64] range under 4G. When crashkernel=X,high > ~~~~ exceeds 80 characters, it should be OK. > >> is passed, kernel could allocate physical memory region >> above 4G, that cause second kernel crash on system >> that require some amount of low memory, e.g. swiotlb >> @@ -857,12 +857,6 @@ >> It will be ignored when crashkernel=X,high is not used >> or memory reserved is below 4G. >> >> - [KNL, ARM64] range in low memory. >> - This one lets the user specify a low range in the >> - DMA zone for the crash dump kernel. >> - It will be ignored when crashkernel=X,high is not used >> - or memory reserved is located in the DMA zones. >> - >> cryptomgr.notests >> [KNL] Disable crypto self-tests >> >> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c >> index 339ee84e5a61a0b..5390f361208ccf7 100644 >> --- a/arch/arm64/mm/init.c >> +++ b/arch/arm64/mm/init.c >> @@ -96,6 +96,14 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1; >> #define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit >> #define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1) >> >> +/* >> + * This is an empirical value in x86_64 and taken here directly. Please >> + * refer to the code comment in reserve_crashkernel_low() of x86_64 for more >> + * details. >> + */ >> +#define DEFAULT_CRASH_KERNEL_LOW_SIZE \ >> + max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20) >> + >> static int __init reserve_crashkernel_low(unsigned long long low_size) >> { >> unsigned long long low_base; >> @@ -147,7 +155,9 @@ static void __init reserve_crashkernel(void) >> * is not allowed. >> */ >> ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base); >> - if (ret && (ret != -ENOENT)) >> + if (ret == -ENOENT) >> + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; >> + else if (ret) >> return; >> >> crash_max = CRASH_ADDR_HIGH_MAX; >> -- >> 2.25.1 >> > > . > -- Regards, Zhen Lei