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=-7.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 2E2E5C433E9 for ; Thu, 3 Sep 2020 13:20:34 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E0ED6206EB for ; Thu, 3 Sep 2020 13:20:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OrxyMScO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0ED6206EB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=7OpAP27h+jcVIj8dc9ZG3mblrNEN2MbpjHDfWsTErZo=; b=OrxyMScOC7VJQMxIPY8aNa26n SndIfuAZmRR2yvx+ReurABnLBPnh740+vp+ee4Me2TSzKqRbyTxv1jwBZalMbJ0qkLEJBsH24UP91 uWXqmVS5zzWdfOAwjqdcqkyhx/V8189odiFmjABXeug5T/nCbgHbN+i9SG1nj1rQUX9LVGeW1gA/j q8orLsNlZRDobpILigDrbZfg6WrYCiu+Dnv+0iQCJkETQhs9rAjd4euSdh2OBQYAVxS/SvEIb/Ksa lDgFwj0ZhEO8WQppnlgV4Uj6R0PviO7unHtj0T6lYCjSQTHvJpAEy7XgFEqymCzmGfaYxnqXN/D2N vMuseRduw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDp93-0005FA-H5; Thu, 03 Sep 2020 13:19:17 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191] helo=huawei.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDp8r-0005B5-Tf; Thu, 03 Sep 2020 13:19:12 +0000 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id C91757B51C7D80ACF500; Thu, 3 Sep 2020 21:18:59 +0800 (CST) Received: from [127.0.0.1] (10.174.176.220) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.487.0; Thu, 3 Sep 2020 21:18:53 +0800 Subject: Re: [PATCH v11 3/5] arm64: kdump: reimplement crashkernel=X To: Catalin Marinas References: <20200801130856.86625-1-chenzhou10@huawei.com> <20200801130856.86625-4-chenzhou10@huawei.com> <20200902170910.GB16673@gaia> From: chenzhou Message-ID: <779fd86d-4d1a-c2ac-ffc8-79f05526a00c@huawei.com> Date: Thu, 3 Sep 2020 21:18:51 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.174.176.220] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200903_091906_308495_CECEE4EA X-CRM114-Status: GOOD ( 17.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wangkefeng.wang@huawei.com, linux-doc@vger.kernel.org, bhsharma@redhat.com, huawei.libin@huawei.com, guohanjun@huawei.com, will@kernel.org, bhe@redhat.com, corbet@lwn.net, mingo@redhat.com, dyoung@redhat.com, John.P.donnelly@oracle.com, arnd@arndb.de, xiexiuqi@huawei.com, horms@verge.net.au, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, james.morse@arm.com, prabhakar.pkin@gmail.com, nsaenzjulienne@suse.de Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020/9/3 19:26, chenzhou wrote: > Hi Catalin, > > > On 2020/9/3 1:09, Catalin Marinas wrote: >> On Sat, Aug 01, 2020 at 09:08:54PM +0800, Chen Zhou wrote: >>> There are following issues in arm64 kdump: >>> 1. We use crashkernel=X to reserve crashkernel below 4G, which >>> will fail when there is no enough low memory. >>> 2. If reserving crashkernel above 4G, in this case, crash dump >>> kernel will boot failure because there is no low memory available >>> for allocation. >>> 3. Since commit 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32"), >>> if the memory reserved for crash dump kernel falled in ZONE_DMA32, >>> the devices in crash dump kernel need to use ZONE_DMA will alloc >>> fail. >>> >>> To solve these issues, change the behavior of crashkernel=X. >>> crashkernel=X tries low allocation in ZONE_DMA, and fall back to >>> high allocation if it fails. >>> >>> If requized size X is too large and leads to very little free memory >>> in ZONE_DMA after low allocation, the system may not work normally. >>> So add a threshold and go for high allocation directly if the required >>> size is too large. The value of threshold is set as the half of >>> the low memory. >>> >>> If crash_base is outside ZONE_DMA, try to allocate at least 256M in >>> ZONE_DMA automatically. "crashkernel=Y,low" can be used to allocate >>> specified size low memory. >> Except for the threshold to keep zone ZONE_DMA memory, >> reserve_crashkernel() looks very close to the x86 version. Shall we try >> to make this generic as well? In the first instance, you could avoid the >> threshold check if it takes an explicit ",high" option. > Ok, i will try to do this. > > I look into the function reserve_crashkernel() of x86 and found the start address is > CRASH_ALIGN in function memblock_find_in_range(), which is different with arm64. > > I don't figure out why is CRASH_ALIGN in x86, is there any specific reason? Besides, in function reserve_crashkernel_low() of x86, the start address is 0. > > Thanks, > Chen Zhou > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > . > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel