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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 267C1C3DA78 for ; Tue, 17 Jan 2023 03:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PKz8guySafmuDyVeVRa+ZdEkvDXl4XCFWQFwfwex/Yw=; b=Fvv2C4lz07qT0P C+MBKpIQs2DRFtFaGNTMVB9VCP2fpoqh+HOGQMiegm1oIbhOfZvuxr4qV7JS+B6FWfKfTe9OUXmvB n/VkWCuuCQZ4fvGf3fQzf1GWmtpGs3FDRYjItjOgeC+8ouGonP390qVRplmgFy9itELxGA86a99N5 7QRtwtZ9IkCxzSFjwEFmzXif+At7TQ8llQx3J9El1oV+XAtvoU/Q8ZwFN9zCm7pvKfXRz6zapnX8q 7L54Q0dxuLctd7LAEO3T5CVqXUcMPWuf6FD6BB/9g3OYCnsmUrtCp/kpGo3SAtvGGvTCPK/HVGdmk 2w/KVocQ5b9AEcIlCapw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pHcyn-00Cnv2-Rs; Tue, 17 Jan 2023 03:49:45 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pHcyj-00CnsG-DN for kexec@lists.infradead.org; Tue, 17 Jan 2023 03:49:42 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673927377; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XKf0pfjvYxPkjbdKZXYck8pY3VTnEaZbMJ46YyM2HTg=; b=ULMT76/BS8uNfBP4vcNcBfAA6obElX32OrJ4e5dU/HZdW59Cp98iTKbpX5suxyeB3GdHT7 +zCBBJSc+zdt3lttV3NBqBHrChPZnS5354IA6LAn3GXGzpPbcyztA2DMuS3dZR0BWob+U0 DiAax2+rik/0pRDhf7g+Dl23w4MBuxg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-482-0KrDAEoOOSGLbtIy3AN8Hg-1; Mon, 16 Jan 2023 22:49:35 -0500 X-MC-Unique: 0KrDAEoOOSGLbtIy3AN8Hg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0D407802BF3; Tue, 17 Jan 2023 03:49:35 +0000 (UTC) Received: from fedora.redhat.com (ovpn-12-229.pek2.redhat.com [10.72.12.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id A08321415108; Tue, 17 Jan 2023 03:49:30 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, thunder.leizhen@huawei.com, John.p.donnelly@oracle.com, wangkefeng.wang@huawei.com, Baoquan He Subject: [PATCH 1/2] arm64: kdump: simplify the reservation behaviour of crashkernel=,high Date: Tue, 17 Jan 2023 11:49:20 +0800 Message-Id: <20230117034921.185150-2-bhe@redhat.com> In-Reply-To: <20230117034921.185150-1-bhe@redhat.com> References: <20230117034921.185150-1-bhe@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230116_194941_559857_7A0F14DB X-CRM114-Status: GOOD ( 18.33 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On arm64, reservation for 'crashkernel=xM,high' is taken by searching for suitable memory region up down. If the 'xM' of crashkernel high memory is reserved from high memory successfully, it will try to reserve crashkernel low memory later accoringly. Otherwise, it will try to search low memory area for the 'xM' suitable region. While we observed an unexpected case where a reserved region crosses the high and low meomry boundary. E.g on a system with 4G as low memory end, user added the kernel parameters like: 'crashkernel=512M,high', it could finally have [4G-126M, 4G+386M], [1G, 1G+128M] regions in running kernel. This looks very strange because we have two low memory regions [4G-126M, 4G] and [1G, 1G+128M]. Much explanation need be given to tell why that happened. Here, for crashkernel=xM,high, search the high memory for the suitable region above the high and low memory boundary. If failed, try reserving the suitable region below the boundary. Like this, the crashkernel high region will only exist in high memory, and crashkernel low region only exists in low memory. The reservation behaviour for crashkernel=,high is clearer and simpler. Signed-off-by: Baoquan He --- arch/arm64/mm/init.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 58a0bb2c17f1..26a05af2bfa8 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -127,12 +127,13 @@ static int __init reserve_crashkernel_low(unsigned long long low_size) */ static void __init reserve_crashkernel(void) { - unsigned long long crash_base, crash_size; - unsigned long long crash_low_size = 0; + unsigned long long crash_base, crash_size, search_base; unsigned long long crash_max = CRASH_ADDR_LOW_MAX; + unsigned long long crash_low_size = 0; char *cmdline = boot_command_line; - int ret; bool fixed_base = false; + bool high = false; + int ret; if (!IS_ENABLED(CONFIG_KEXEC_CORE)) return; @@ -155,7 +156,9 @@ static void __init reserve_crashkernel(void) else if (ret) return; + search_base = CRASH_ADDR_LOW_MAX; crash_max = CRASH_ADDR_HIGH_MAX; + high = true; } else if (ret || !crash_size) { /* The specified value is invalid */ return; @@ -166,31 +169,44 @@ static void __init reserve_crashkernel(void) /* User specifies base address explicitly. */ if (crash_base) { fixed_base = true; + search_base = crash_base; crash_max = crash_base + crash_size; } retry: crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, - crash_base, crash_max); + search_base, crash_max); if (!crash_base) { + if (fixed_base) { + pr_warn("cannot reserve crashkernel region [0x%llx-0x%llx]\n", + search_base, crash_max); + return; + } + /* * If the first attempt was for low memory, fall back to * high memory, the minimum required low memory will be * reserved later. */ - if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) { + if (!high && crash_max == CRASH_ADDR_LOW_MAX) { crash_max = CRASH_ADDR_HIGH_MAX; + search_base = CRASH_ADDR_LOW_MAX; crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; goto retry; } + if (high && (crash_max == CRASH_ADDR_HIGH_MAX)) { + crash_max = CRASH_ADDR_LOW_MAX; + search_base = 0; + goto retry; + } pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size); return; } - if ((crash_base > CRASH_ADDR_LOW_MAX - crash_low_size) && - crash_low_size && reserve_crashkernel_low(crash_low_size)) { + if ((crash_base >= CRASH_ADDR_LOW_MAX) && crash_low_size && + reserve_crashkernel_low(crash_low_size)) { memblock_phys_free(crash_base, crash_size); return; } -- 2.34.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec