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 7AF53C77B7C for ; Wed, 31 May 2023 07:48:45 +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=rSC0ZRCBZdd6+0gkDl52UrH2RI2i0UcQi9jl0duobfY=; b=X7WP+ECcnsIn09 x/6bF+8DFRJwHUzIh+gYUX2w6M3v8pwaJ7Wx/HiolZle23bfnT0yZQRa2A9xQEndOEv1IRG/2T4Qh IeNQUnJXMQLNLnVU9wyVJRqVdIOchBWZ21u6FJKYubOBXsrF8RgJSFeO5bNEXKLyLifgOA/xqlj2D BTfrVAv4QDLtxRIVVyRLpFg0K1vpwGKeY67mTHPcpLybIQcm6MmtMoJMS1/WyBONXM5mLuR/YKyWv 274B/cuU7hCIT2vqH8DBD/z9RYD4x+rX1wu5FJ8m7wi7/rGv4nIbQZGpWnOUADk6aq5m7ZGqGPSyz +EsrRFs7LxRXvFQuZDYA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q4GZW-00GVWb-1p; Wed, 31 May 2023 07:48:42 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q4GZU-00GVW1-0O for kexec@lists.infradead.org; Wed, 31 May 2023 07:48:41 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685519319; 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=lN0vUYVvRFjvHRoECulLsT+QfP7ftEVA/sIPfwf8rQA=; b=Z5iG+cl85+VEXCz4FJ1VwvqMoad6lgET/0Jz5Pk+klyHk/C465J/zN0RLM2+P6XvplXuHR wArS+1wAQphEUeVyi4ilI9F+7xdJmLLyIz5nXKugncTMeYya8ie4H6317D5qf4zZ/YSqFb vGcIbGhlTLqUzgjV/YHwgwdnHmtCPXY= 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-402-Q2H1UejbNMiemtkarHc2zQ-1; Wed, 31 May 2023 03:48:35 -0400 X-MC-Unique: Q2H1UejbNMiemtkarHc2zQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1F9C3858F0F; Wed, 31 May 2023 07:48:35 +0000 (UTC) Received: from localhost (ovpn-12-54.pek2.redhat.com [10.72.12.54]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4601B2166B25; Wed, 31 May 2023 07:48:33 +0000 (UTC) Date: Wed, 31 May 2023 15:48:30 +0800 From: Baoquan He To: Zhen Lei Cc: Eric Biederman , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Michael Holzheu , Andrew Morton Subject: Re: [PATCH 4/6] kexec: improve the readability of crash_shrink_memory() Message-ID: References: <20230527123439.772-1-thunder.leizhen@huawei.com> <20230527123439.772-5-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230527123439.772-5-thunder.leizhen@huawei.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230531_004840_230248_BDE4DDFB X-CRM114-Status: GOOD ( 23.74 ) 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 05/27/23 at 08:34pm, Zhen Lei wrote: > The major adjustments are: > 1. end = start + new_size. > The 'end' here is not an accurate representation, because it is not the > new end of crashk_res, but the start of ram_res, difference 1. So > eliminate it and replace it with ram_res->start. > 2. Use 'ram_res->start' and 'ram_res->end' as arguments to > crash_free_reserved_phys_range() to indicate that the memory covered by > 'ram_res' is released from the crashk. And keep it close to > insert_resource(). > 3. Replace 'if (start == end)' with 'if (!new_size)', clear indication that > all crashk memory will be shrunken. > > No functional change. > > Signed-off-by: Zhen Lei LGTM, Acked-by: Baoquan He > --- > kernel/kexec_core.c | 15 +++++---------- > 1 file changed, 5 insertions(+), 10 deletions(-) > > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index bcc86a250ab3bf9..69fe92141b0b62d 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -1108,7 +1108,6 @@ ssize_t crash_get_memory_size(void) > int crash_shrink_memory(unsigned long new_size) > { > int ret = 0; > - unsigned long start, end; > unsigned long old_size; > struct resource *ram_res; > > @@ -1119,9 +1118,7 @@ int crash_shrink_memory(unsigned long new_size) > ret = -ENOENT; > goto unlock; > } > - start = crashk_res.start; > - end = crashk_res.end; > - old_size = (end == 0) ? 0 : end - start + 1; > + old_size = !crashk_res.end ? 0 : resource_size(&crashk_res); > new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN); > if (new_size >= old_size) { > ret = (new_size == old_size) ? 0 : -EINVAL; > @@ -1134,22 +1131,20 @@ int crash_shrink_memory(unsigned long new_size) > goto unlock; > } > > - end = start + new_size; > - crash_free_reserved_phys_range(end, crashk_res.end); > - > - ram_res->start = end; > + ram_res->start = crashk_res.start + new_size; > ram_res->end = crashk_res.end; > ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM; > ram_res->name = "System RAM"; > > - if (start == end) { > + if (!new_size) { > release_resource(&crashk_res); > crashk_res.start = 0; > crashk_res.end = 0; > } else { > - crashk_res.end = end - 1; > + crashk_res.end = ram_res->start - 1; > } > > + crash_free_reserved_phys_range(ram_res->start, ram_res->end); > insert_resource(&iomem_resource, ram_res); > > unlock: > -- > 2.25.1 > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec