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 99691C54E94 for ; Tue, 24 Jan 2023 02:50:02 +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=IRCYfxGBBHUvyec3zJu2HAfYiZSms2OZ353cXv+XJr8=; b=n6vaXL/MqqjQvj +smsWnzDtGvcDxUnlm/qfGvqm5y/dRckcKdzDqllOydXsF5sI5GpO01flXuGq8mM8pGLAouVteWl2 jU+g8dFbvffU4hC/E5irRHD/3acu0Vk+VwWWg9MrZaMAQCmfO6cI49TKYkssLc54gGAJ7HR4J3T45 2IyzicRFPWUIwn7lauDozSffAjUhbIXTlkQmDq1BTVdfmGuKBvjEtxIYMNb8g9qelBiCVbaRSzKkN nmko77t5QTceI5DEFr5h+jcmGa1A1S/xJBGAWkT2MqhkyCFzYJi5WsH6TPJ011i0mgcohTOUgIiuq vwaHnWCTQmYIfIqM9sEg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pK9Nj-0028OX-PC; Tue, 24 Jan 2023 02:49:55 +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 1pK9Ng-0028NM-1C for kexec@lists.infradead.org; Tue, 24 Jan 2023 02:49:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674528590; 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=tDEShTc+qxEMTNcIsETbduQ+QSQW/4E7thNs06NrHuI=; b=RRv+k+9frVG95OjJax32o0aR4EcILedyLs3VYU1MEsp99ya2tWd5BKe8UNMrYoh/y3FMEx N8erMWM1xGjWwciXe8fwSBUPto9WFiICXBEf+8bzBf6f5BKYwfZoR2msETA+AONpqbDJPw OU44QS84+fTqlrZH7b0sjFBOS3oRFMk= 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-56-ajSWj7FDNyGCHfrOcokx7g-1; Mon, 23 Jan 2023 21:49:48 -0500 X-MC-Unique: ajSWj7FDNyGCHfrOcokx7g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CE1E385C069; Tue, 24 Jan 2023 02:49:47 +0000 (UTC) Received: from localhost (ovpn-12-81.pek2.redhat.com [10.72.12.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 607FC4069768; Tue, 24 Jan 2023 02:49:45 +0000 (UTC) Date: Tue, 24 Jan 2023 10:49:42 +0800 From: Baoquan He To: Simon Horman Cc: linux-kernel@vger.kernel.org, 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 Subject: Re: [PATCH 2/2] arm64/kdump: add code comments for crashkernel reservation cases Message-ID: References: <20230117034921.185150-1-bhe@redhat.com> <20230117034921.185150-3-bhe@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230123_184952_165729_BB32B4AA X-CRM114-Status: GOOD ( 32.30 ) 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 01/20/23 at 10:02am, Simon Horman wrote: > On Tue, Jan 17, 2023 at 11:49:21AM +0800, Baoquan He wrote: > > This will help understand codes on crashkernel reservations on arm64. > > FWIIW, I think you can fold this into the first patch. Sure, will do. I folded this into patch 1 at the very beginning. Then felt the added code comments add lines of change and make the code change not so straightforward. I admit it's from personal feeling. > > And, although I have no good idea at this moment, I do wonder > if the logic can be simplified - I for one really needed the > comments to understand the retry logic. Got it. I will consider if I can improve the logic readability. Thanks. > > > Signed-off-by: Baoquan He > > --- > > arch/arm64/mm/init.c | 13 +++++++++++++ > > 1 file changed, 13 insertions(+) > > > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > > index 26a05af2bfa8..f88ad17cb20d 100644 > > --- a/arch/arm64/mm/init.c > > +++ b/arch/arm64/mm/init.c > > @@ -177,6 +177,10 @@ static void __init reserve_crashkernel(void) > > crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, > > search_base, crash_max); > > if (!crash_base) { > > + /* > > + * For crashkernel=size[KMG]@offset[KMG], print out failure > > + * message if can't reserve the specified region. > > + */ > > if (fixed_base) { > > pr_warn("cannot reserve crashkernel region [0x%llx-0x%llx]\n", > > search_base, crash_max); > > @@ -188,6 +192,11 @@ static void __init reserve_crashkernel(void) > > * high memory, the minimum required low memory will be > > * reserved later. > > */ > > + /* > > + * 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. > > + */ > > I think this duplicates the preceding comment. > Perhaps just replace the earlier comment with this one. > > > if (!high && crash_max == CRASH_ADDR_LOW_MAX) { > > crash_max = CRASH_ADDR_HIGH_MAX; > > search_base = CRASH_ADDR_LOW_MAX; > > @@ -195,6 +204,10 @@ static void __init reserve_crashkernel(void) > > 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)) { > > crash_max = CRASH_ADDR_LOW_MAX; > > search_base = 0; > > -- > > 2.34.1 > > > > > > _______________________________________________ > > kexec mailing list > > kexec@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/kexec > > > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec