From: Jianguo Wu <wujianguo@huawei.com>
To: Tang Chen <tangchen@cn.fujitsu.com>
Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
linux-mm@kvack.org, paulus@samba.org, sparclinux@vger.kernel.org,
Christoph Lameter <cl@linux.com>,
linux-s390@vger.kernel.org, x86@kernel.org,
linux-acpi@vger.kernel.org,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Jiang Liu <liuj97@gmail.com>, Len Brown <len.brown@intel.com>,
Jiang Liu <jiang.liu@huawei.com>,
Wen Congyang <wency@cn.fujitsu.com>,
cmetcalf@tilera.com, linux-kernel@vger.kernel.org,
Minchan Kim <minchan.kim@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [Patch v4 09/12] memory-hotplug: remove page table of x86_64 architecture
Date: Fri, 7 Dec 2012 15:06:16 +0800 [thread overview]
Message-ID: <50C19568.7080500@huawei.com> (raw)
In-Reply-To: <50C19022.9000501@cn.fujitsu.com>
On 2012/12/7 14:43, Tang Chen wrote:
> 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.
>
Hi Tang,
Virtual addresses will work fine, I used physical addresses in order to
keep consistent with phys_pud[pmd/pte]_init(), So I think we should keep this.
Thanks,
Jianguo Wu
> 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
>
>
>
> .
>
next prev parent reply other threads:[~2012-12-07 7:06 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-27 10:00 [Patch v4 00/12] memory-hotplug: hot-remove physical memory Wen Congyang
2012-11-27 10:00 ` [Patch v4 01/12] memory-hotplug: try to offline the memory twice to avoid dependence Wen Congyang
2012-12-04 9:17 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 02/12] memory-hotplug: check whether all memory blocks are offlined or not when removing memory Wen Congyang
2012-12-04 9:22 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 03/12] memory-hotplug: remove redundant codes Wen Congyang
2012-12-04 9:22 ` Tang Chen
2012-12-04 10:31 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 04/12] memory-hotplug: remove /sys/firmware/memmap/X sysfs Wen Congyang
2012-11-27 10:00 ` [Patch v4 05/12] memory-hotplug: introduce new function arch_remove_memory() for removing page table depends on architecture Wen Congyang
2012-12-04 9:30 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP Wen Congyang
2012-12-04 9:34 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 07/12] memory-hotplug: implement register_page_bootmem_info_section of sparse-vmemmap Wen Congyang
2012-11-27 10:00 ` [Patch v4 08/12] memory-hotplug: remove memmap " Wen Congyang
2012-11-28 9:40 ` Jianguo Wu
2012-11-30 1:45 ` Wen Congyang
2012-11-30 2:47 ` Jianguo Wu
2012-11-30 2:55 ` Yasuaki Ishimatsu
2012-12-03 2:23 ` Jianguo Wu
2012-12-04 9:13 ` Tang Chen
2012-12-04 12:20 ` Jianguo Wu
2012-12-05 2:07 ` Tang Chen
2012-12-05 3:23 ` Jianguo Wu
2012-12-07 1:42 ` Tang Chen
2012-12-07 2:20 ` Jianguo Wu
2012-12-04 9:47 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 09/12] memory-hotplug: remove page table of x86_64 architecture Wen Congyang
2012-12-07 6:43 ` Tang Chen
2012-12-07 7:06 ` Jianguo Wu [this message]
2012-11-27 10:00 ` [Patch v4 10/12] memory-hotplug: memory_hotplug: clear zone when removing the memory Wen Congyang
2012-12-04 10:09 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 11/12] memory-hotplug: remove sysfs file of node Wen Congyang
2012-12-04 10:10 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 12/12] memory-hotplug: free node_data when a node is offlined Wen Congyang
2012-12-04 10:10 ` Tang Chen
2012-11-27 19:27 ` [Patch v4 00/12] memory-hotplug: hot-remove physical memory Andrew Morton
2012-11-27 19:38 ` Rafael J. Wysocki
2012-11-28 0:43 ` Yasuaki Ishimatsu
2012-11-30 6:37 ` Tang Chen
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