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 05616C7EE32 for ; Fri, 3 Mar 2023 03:02:31 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZfNemK8bm+XVAqvl7kH3PSI0MFmY4MF+/nzAesXr5gc=; b=nMzGFG2lkLdHHs Kv+KM2f9pPLDr+VzUzfafNG+hnsv0t0K4JNOxVGbhAgfu3QDKMuiWCRTkmPTMgbShh6Dy5NW7pUpz 6etqetRfq4v6IquEkMd8ylhuzpwQzp3xVH3ZQyTDWqonZU8qPB7t6OYHgg/ER8kqWjy/TwwzuVNMl tVsTdOJv/XQLTm0LD6g1NEg5bfMHM8klxnz2B7dxa/ZFDms68+xUVdjiXcAQGjpv7Fbgt6NqKNHaP dewtY+yLc52wDjLNVUp4V8dmGqBIIMvraWxk/YWoFbBi3bqbp9uqnFjjyWlvmw/Oi1L9adSAscfaB mkVUVSKo2wyoBLisyZNQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXvfp-004at0-Az; Fri, 03 Mar 2023 03:01:33 +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 1pXvfl-004arT-V2 for linux-arm-kernel@lists.infradead.org; Fri, 03 Mar 2023 03:01:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677812486; 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: in-reply-to:in-reply-to:references:references; bh=B79nsr/L+yxY5ZiHIGPfHGlquDm1c+TbNdmntyfdbOk=; b=U3vT5UNC/U+OoaZCqPrZc/cunrQH/jurpwyE170YDRxfyOtdf3vhiaDUjsu+Jkv66LGCSo WDXQT6e+CEKDNjhXtmVc1tdOiTRwDTM6eP0wxKATtBHa7b1K2RBE5gx1uUAd5Gi1qG+FEd Ep6+qoHFGdEB31d1xDfOOApX0qbmw4U= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-624-kfVt7ZOyPxuBPOeHxtUHfg-1; Thu, 02 Mar 2023 22:01:25 -0500 X-MC-Unique: kfVt7ZOyPxuBPOeHxtUHfg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B6E8F280BF64; Fri, 3 Mar 2023 03:01:24 +0000 (UTC) Received: from localhost (ovpn-13-150.pek2.redhat.com [10.72.13.150]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9B93040C6EC4; Fri, 3 Mar 2023 03:01:22 +0000 (UTC) Date: Fri, 3 Mar 2023 11:01:19 +0800 From: Baoquan He To: "Leizhen (ThunderTown)" Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com, horms@kernel.org, John.p.donnelly@oracle.com, will@kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3] arm64: kdump: simplify the reservation behaviour of crashkernel=,high Message-ID: References: <20230223124532.128744-1-bhe@redhat.com> <7971ddbe-aefb-271e-647c-59d81c5840a7@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <7971ddbe-aefb-271e-647c-59d81c5840a7@huawei.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230302_190130_109951_AC8CBC3D X-CRM114-Status: GOOD ( 22.70 ) X-BeenThere: linux-arm-kernel@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: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 03/02/23 at 11:32am, Leizhen (ThunderTown) wrote: ...... > > @@ -166,31 +169,51 @@ 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 the first attempt was for low memory, fall back to > > - * high memory, the minimum required low memory will be > > - * reserved later. > > + * For crashkernel=size[KMG]@offset[KMG], print out failure > > + * message if can't reserve the specified region. > > */ > > - if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) { > > + if (fixed_base) { > > + pr_info("crashkernel reservation failed - memory is in use.\n"); > > How about changing pr_info to pr_warn? > > > + return; > > + } > > + > > + /* > > + * For crashkernel=size[KMG], if the first attempt was for > > + * low memory, fall back to high memory, the minimum required > > + * low memory will be reserved later. > > + */ > > + 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; > > } > > > > + /* > > + * For crashkernel=size[KMG],high, if the first attempt was > > + * for high memory, fall back to low memory. > > + */ > > + if (high && crash_max == CRASH_ADDR_HIGH_MAX) { > > Adding unlikely to indicate that it is rare would be better. > > if (unlikely(high && crash_max == CRASH_ADDR_HIGH_MAX)) Rethink about this and checked code in kernel, seems likely|unlikely are mostly used in highly frequent execution branch optimize code path, while crashkernel resevatoin is one time execution during boot, we may not need to bother to add unlikely. What do you think? > > > + 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; > > } > > > > -- > Regards, > Zhen Lei > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel