Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756431Ab0KRKl6 (ORCPT ); Thu, 18 Nov 2010 05:41:58 -0500 Received: from mga11.intel.com ([192.55.52.93]:51964 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755832Ab0KRKl5 (ORCPT ); Thu, 18 Nov 2010 05:41:57 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,216,1288594800"; d="scan'208";a="627985361" Date: Thu, 18 Nov 2010 17:20:52 +0800 From: Shaohui Zheng To: David Rientjes Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, haicheng.li@linux.intel.com, lethal@linux-sh.org, ak@linux.intel.com, shaohui.zheng@linux.intel.com, Yinghai Lu , Haicheng Li Subject: Re: [1/8,v3] NUMA Hotplug Emulator: add function to hide memory region via e820 table. Message-ID: <20101118092052.GE2408@shaohui> References: <20101117020759.016741414@intel.com> <20101117021000.479272928@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2306 Lines: 71 On Wed, Nov 17, 2010 at 12:16:34AM -0800, David Rientjes wrote: > On Wed, 17 Nov 2010, shaohui.zheng@intel.com wrote: > > > Index: linux-hpe4/arch/x86/kernel/e820.c > > =================================================================== > > --- linux-hpe4.orig/arch/x86/kernel/e820.c 2010-11-15 17:13:02.483461667 +0800 > > +++ linux-hpe4/arch/x86/kernel/e820.c 2010-11-15 17:13:07.083461581 +0800 > > @@ -971,6 +971,7 @@ > > } > > > > static int userdef __initdata; > > +static u64 max_mem_size __initdata = ULLONG_MAX; > > > > /* "mem=nopentium" disables the 4MB page tables. */ > > static int __init parse_memopt(char *p) > > @@ -989,12 +990,28 @@ > > > > userdef = 1; > > mem_size = memparse(p, &p); > > - e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1); > > + e820_remove_range(mem_size, max_mem_size - mem_size, E820_RAM, 1); > > + max_mem_size = mem_size; > > > > return 0; > > } > > This needs memmap= support as well, right? we did not do the testing after combine both memmap and numa=hide paramter, I think that the result should similar with mem=XX, they both remove a memory region from the e820 table. > > > early_param("mem", parse_memopt); > > > > +#ifdef CONFIG_NODE_HOTPLUG_EMU > > +u64 __init e820_hide_mem(u64 mem_size) > > +{ > > + u64 start, end_pfn; > > + > > + userdef = 1; > > + end_pfn = e820_end_of_ram_pfn(); > > + start = (end_pfn << PAGE_SHIFT) - mem_size; > > + e820_remove_range(start, max_mem_size - start, E820_RAM, 1); > > + max_mem_size = start; > > + > > + return start; > > +} > > +#endif > > This doesn't have any sanity checking for whether e820_remove_range() will > leave any significant amount of memory behind so the kernel will even boot > (probably should have a guaranteed FAKE_NODE_MIN_SIZE left behind?). it should not be checked here, it should be checked by the function who call e820_hide_mem, and truncate the mem_size with FAKE_NODE_MIN_SIZE. > > > + > > static int __init parse_memmap_opt(char *p) > > { > > char *oldp; -- Thanks & Regards, Shaohui -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/