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 19A00C433E2 for ; Thu, 3 Sep 2020 11:29:26 +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 D25EB2083B for ; Thu, 3 Sep 2020 11:29:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="1C51mMb6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D25EB2083B 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=MkuzsyjzbhmQeDQdX/CJUSMxyqagHTtI9KlZNJu9ark=; b=1C51mMb6jshrtgqkYTUoubsH6 TeVKaOzfCsF2DwTSZKOsj30S+CFvfZCE97aiEQDoFbxfpVMlT2QJJSAbFcJX/3w9Cf3IN+g73Ky2b hKiblZ7lu5Z5zBJN50J+/cj3PyDS81ye8h0g2NsY/aklguBq5Ta9MkGFMLFrjw63AK5pXSMkis5X2 ytB72b8I9Sw2C4oI++o3AnWhEdkyZkEjPW64y3VKCbAZ2qky7BiT87p38BqVnAk8ABeVEktfes3mP m9/7WtvMCyXrGrD0iF9tHHoyt/JFzyxNV0iHoMg99yvDluL5TXoao1infSiMTOY2jSdKpAjqfRso4 bnsKIYoQw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDnOu-0002xG-P6; Thu, 03 Sep 2020 11:27:32 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32] helo=huawei.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDnOE-0002VV-8O; Thu, 03 Sep 2020 11:26:52 +0000 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 4F8BB9C923A5A99C2CA7; Thu, 3 Sep 2020 19:26:39 +0800 (CST) Received: from [127.0.0.1] (10.174.176.220) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.487.0; Thu, 3 Sep 2020 19:26:28 +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: Date: Thu, 3 Sep 2020 19:26:27 +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: <20200902170910.GB16673@gaia> 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_072650_548244_D51D686F X-CRM114-Status: GOOD ( 14.85 ) 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 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? Thanks, Chen Zhou _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel