Thanks Peter, my testing shows that there are many issues on 32-bit kernel for memory hot-add, there are still more works to do for 32-bit kernels(more than 2 patches). Memory hot-add is much more important on 64-bit kernel, I think that we can fix the bug on 64-bit kernel first. 32-kernel hotplug is the working in next step. Thanks & Regards, Shaohui -----Original Message----- From: H. Peter Anvin [mailto:hpa@kernel.org] Sent: Friday, January 08, 2010 1:03 PM To: Zheng, Shaohui Cc: linux-mm@kvack.org; akpm@linux-foundation.org; linux-kernel@vger.kernel.org; ak@linux.intel.com; y-goto@jp.fujitsu.com; Dave Hansen; Wu, Fengguang; x86@kernel.org Subject: Re: [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1) On 01/07/2010 07:32 PM, Zheng, Shaohui wrote: > Resend the patch to the mailing-list, the original patch URL is > http://patchwork.kernel.org/patch/69075/, it is not accepted without comments, > sent it again to review. > > Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel > > The new added memory can not be access by interface /dev/mem, because we do not > update the variable high_memory. This patch add a new e820 entry in e820 table, > and update max_pfn, max_low_pfn and high_memory. > > We add a function update_pfn in file arch/x86/mm/init.c to udpate these > varibles. Memory hotplug does not make sense on 32-bit kernel, so we did not > concern it in this function. > Memory hotplug makes sense on 32-bit kernels, at least in virtual environments. -hpa {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I