From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mga03.intel.com ([143.182.124.21]) by canuck.infradead.org with esmtp (Exim 4.72 #1 (Red Hat Linux)) id 1P3vbu-0007k5-9u for kexec@lists.infradead.org; Thu, 07 Oct 2010 18:54:35 +0000 Message-ID: <4CAE1767.5040409@intel.com> Date: Thu, 07 Oct 2010 11:54:31 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [tip:core/memblock] x86, memblock: Fix crashkernel allocation References: <4CABAF2A.5090501@kernel.org> <20101006151449.GA7378@redhat.com> <4CACF531.2060407@intel.com> <20101006224704.GD7378@redhat.com> <4CAD01A9.9050907@intel.com> <20101007181804.GE23308@redhat.com> In-Reply-To: <20101007181804.GE23308@redhat.com> 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-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Vivek Goyal Cc: "caiqian@redhat.com" , "linux-tip-commits@vger.kernel.org" , Kexec Mailing List , "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "tglx@linutronix.de" , "yinghai@kernel.org" On 10/07/2010 11:18 AM, Vivek Goyal wrote: > > Ok, I was browsing through kexec-tools, x86 bzImage code and trying to > refresh my memory what segments were being loaded and what were memory > address concerns. > > - relocatable bzImage (max addr 0x37ffffff, 896MB). > Though I don't know/understand where that 896MB come from. > > - initrd (max addr 0x37ffffff, 896MB) > Don't know why 896MB as upper limit 896 MB is presumably the (default!!) LOWMEM limit on 32 bits. This is actually wrong if vmalloc= is also specified on command line, though, or with nonstandard compile-time options. > - Purgatory (max addr 2G) > > - A segment to keep elf headers (no limit) > These are accessed when second kernel as fully booted so can be > addressed in higher addresses. > > - A backup segment to copy first 640K of memory (not aware of any limit) > - Setup/parameter segment (no limit) > - We don't really execute anything here and just access it for > command line. Probably has a 4 GB limit, since I believe it only has a 32-bit pointer. > So atleast for bzImage it looks that if we specify crashkernel=128M<896M, it > will work. > > So I am fine with above additional syntax for crashkernel=. May be we shall > have to the deprecate the crashkernel=X<@0 syntax. > > CCing kexec list, in case others have any comments. It would be easy enough to either deprecate or make it an alias for crashkernel=...<896M, which is basically what Yinghai's patch does. -hpa _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec