From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F232145A07 for ; Tue, 27 Aug 2024 09:02:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724749334; cv=none; b=Fkj9T4cpwNWPu2NwjudQL/zxWG8VkPm5jcTl8R4OTvMUQmayseuJ2zMVa/qTygmusZpIvMnBDojX0uzbSKgTvBhbv5TK3MSBqnGSeA10/IYSkLoOnLG4AphTdbu95hpo/6ZjQc3ejMQ7w3fsJ81bvkT3E37E8P9dlQzcOWRRuzU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724749334; c=relaxed/simple; bh=CNgje/G2UMnIInNFSzspq8/Z5XpdG66fBhV4nVsqiOw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RewjuS/Ssx4mrzB1iq09cHiMa/wbfcVpCkQMwm/K1JCuTHsNGY/vz6PEYytc12b/HjAPDvHiwBuPOqVH3bffQfND6s4N2Fj504Osl5+no6AuNOcybMCqafZRGYNaM5C4ljDr3rp4EYpEt3oS++BOImhnQ9J+gpdfcZxZOoRbVbc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=QRJ3IODC; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QRJ3IODC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724749331; 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=outpxqXc6KM2Oo4/0nqD4smTGWGwDj3DOJrNewpgErA=; b=QRJ3IODCcxnV/ov4GlcWuZG9AaYnj6Z6W07GTkdKAfrzlGlxnJ7SYQXgQHloQzCe1Ix4Jj 4hoSKYaHoq5+SKSbMd8T/X/NyJELLuDi7S6CNbdhHIc150X6RKmvug5ou8OhiWO0fQenGz W98glv5gmvUIO8LCTDPui1nOtCST9ME= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-468-rv4ABExJM5egEclpNPuyLA-1; Tue, 27 Aug 2024 05:02:08 -0400 X-MC-Unique: rv4ABExJM5egEclpNPuyLA-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7B6471955BFE; Tue, 27 Aug 2024 09:02:05 +0000 (UTC) Received: from localhost (unknown [10.72.112.42]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 416C019560AA; Tue, 27 Aug 2024 09:02:02 +0000 (UTC) Date: Tue, 27 Aug 2024 17:01:58 +0800 From: Baoquan He To: John Paul Adrian Glaubitz Cc: Geert Uytterhoeven , Dave Vasilevsky , linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org, mpe@ellerman.id.au, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Reimar =?iso-8859-1?Q?D=F6ffinger?= Subject: Re: [PATCH] crash: Default to CRASH_DUMP=n when support for it is unlikely Message-ID: References: <20240823125156.104775-1-dave@vasilevsky.ca> <09c29a3c4879d4ce5d8b97fd60d8ba5e38bed979.camel@physik.fu-berlin.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 On 08/27/24 at 08:37am, John Paul Adrian Glaubitz wrote: > On Tue, 2024-08-27 at 14:22 +0800, Baoquan He wrote: > > About why it's enabled by default, as Michael has explained in another > > thread, distros usualy needs to enable it by default because vmcore > > dumping is a very important feature on servers, even guest instances. > > Even though kdump codes are enabled to built in, not providing > > crashkernel= value won't make vmcore dumping take effect, it won't cost > > system resources in that case. > > OK, thanks for the explanation. But as we have found out in the mean time, > the assumption was wrong to enable it by default for all architectures as > some architectures cannot boot a crash dump kernel with their default bootloader > but only through kexec. > > Can we have a follow-up patch to disable crash dump kernels where they're > not needed? I mean, not every platform supported by Linux is obviously a > x86-based or POWER-based server. Yes, while isn't Dave's patch a good one to fix it? In Dave's patch, the default enabling of CRASH_DUMP has been taken off, change to rely on ARCH_DEFAULT_CRASH_DUMP provided by each arch. config CRASH_DUMP bool "kernel crash dumps" - default y + default ARCH_DEFAULT_CRASH_DUMP