From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx112.postini.com [74.125.245.112]) by kanga.kvack.org (Postfix) with SMTP id 1B56F6B005D for ; Fri, 7 Dec 2012 01:44:45 -0500 (EST) Message-ID: <50C19022.9000501@cn.fujitsu.com> Date: Fri, 07 Dec 2012 14:43:46 +0800 From: Tang Chen MIME-Version: 1.0 Subject: Re: [Patch v4 09/12] memory-hotplug: remove page table of x86_64 architecture References: <1354010422-19648-1-git-send-email-wency@cn.fujitsu.com> <1354010422-19648-10-git-send-email-wency@cn.fujitsu.com> In-Reply-To: <1354010422-19648-10-git-send-email-wency@cn.fujitsu.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linux-mm@kvack.org List-ID: To: Wen Congyang Cc: x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org, David Rientjes , Jiang Liu , Len Brown , benh@kernel.crashing.org, paulus@samba.org, Christoph Lameter , Minchan Kim , Andrew Morton , KOSAKI Motohiro , Yasuaki Ishimatsu , Jianguo Wu , Jiang Liu On 11/27/2012 06:00 PM, Wen Congyang wrote: > For hot removing memory, we sholud remove page table about the memory. > So the patch searches a page table about the removed memory, and clear > page table. (snip) > +void __meminit > +kernel_physical_mapping_remove(unsigned long start, unsigned long end) > +{ > + unsigned long next; > + bool pgd_changed = false; > + > + start = (unsigned long)__va(start); > + end = (unsigned long)__va(end); Hi Wu, Here, you expect start and end are physical addresses. But in phys_xxx_remove() function, I think using virtual addresses is just fine. Functions like pmd_addr_end() and pud_index() only calculate an offset. So, would you please tell me if we have to use physical addresses here ? Thanks. :) > + > + for (; start< end; start = next) { > + pgd_t *pgd = pgd_offset_k(start); > + pud_t *pud; > + > + next = pgd_addr_end(start, end); > + > + if (!pgd_present(*pgd)) > + continue; > + > + pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd)); > + phys_pud_remove(pud, __pa(start), __pa(next)); > + if (free_pud_table(pud, pgd)) > + pgd_changed = true; > + unmap_low_page(pud); > + } > + > + if (pgd_changed) > + sync_global_pgds(start, end - 1); > + > + flush_tlb_all(); > +} > + > #ifdef CONFIG_MEMORY_HOTREMOVE > int __ref arch_remove_memory(u64 start, u64 size) > { > @@ -692,6 +921,8 @@ int __ref arch_remove_memory(u64 start, u64 size) > ret = __remove_pages(zone, start_pfn, nr_pages); > WARN_ON_ONCE(ret); > > + kernel_physical_mapping_remove(start, start + size); > + > return ret; > } > #endif -- 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