From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 5 Sep 2008 19:44:49 +0200 From: Ingo Molnar Subject: Re: [PATCH] [RESEND] x86_64: add memory hotremove config option Message-ID: <20080905174449.GC27395@elte.hu> References: <20080905172132.GA11692@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080905172132.GA11692@us.ibm.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Gary Hade Cc: linux-mm@kvack.org, Andrew Morton , Yasunori Goto , Badari Pulavarty , Mel Gorman , Chris McDermott , linux-kernel@vger.kernel.org, x86@kernel.org List-ID: * Gary Hade wrote: > Add memory hotremove config option to x86_64 > > Memory hotremove functionality can currently be configured into the > ia64, powerpc, and s390 kernels. This patch makes it possible to > configure the memory hotremove functionality into the x86_64 kernel as > well. hm, why is it for 64-bit only? > +++ linux-2.6.27-rc5/arch/x86/Kconfig 2008-09-03 13:34:55.000000000 -0700 > @@ -1384,6 +1384,9 @@ > def_bool y > depends on X86_64 || (X86_32 && HIGHMEM) > > +config ARCH_ENABLE_MEMORY_HOTREMOVE > + def_bool y so this will break the build on 32-bit, if CONFIG_MEMORY_HOTREMOVE=y? mm/memory_hotplug.c assumes that remove_memory() is provided by the architecture. > +#ifdef CONFIG_MEMORY_HOTREMOVE > +int remove_memory(u64 start, u64 size) > +{ > + unsigned long start_pfn, end_pfn; > + unsigned long timeout = 120 * HZ; > + int ret; > + start_pfn = start >> PAGE_SHIFT; > + end_pfn = start_pfn + (size >> PAGE_SHIFT); > + ret = offline_pages(start_pfn, end_pfn, timeout); > + if (ret) > + goto out; > + /* Arch-specific calls go here */ > +out: > + return ret; > +} > +EXPORT_SYMBOL_GPL(remove_memory); > +#endif /* CONFIG_MEMORY_HOTREMOVE */ hm, nothing appears to be arch-specific about this trivial wrapper around offline_pages(). Shouldnt this be moved to the CONFIG_MEMORY_HOTREMOVE portion of mm/memory_hotplug.c instead, as a weak function? That way architectures only have to enable ARCH_ENABLE_MEMORY_HOTREMOVE - and architectures with different/special needs can override it. Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org