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Message-ID: <5007D3AB.4080401@jp.fujitsu.com>
Date: Thu, 19 Jul 2012 18:30:19 +0900
From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To: Bob Liu <lliubbo@...il.com>
CC: <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
<linuxppc-dev@...ts.ozlabs.org>, <linux-acpi@...r.kernel.org>,
<rientjes@...gle.com>, <liuj97@...il.com>, <len.brown@...el.com>,
<benh@...nel.crashing.org>, <paulus@...ba.org>, <cl@...ux.com>,
<minchan.kim@...il.com>, <akpm@...ux-foundation.org>,
<kosaki.motohiro@...fujitsu.com>, <wency@...fujitsu.com>
Subject: Re: [RFC PATCH v4 7/13] memory-hotplug : remove_memory calls __remove_pages
Hi Bob,
2012/07/19 17:32, Bob Liu wrote:
> On Wed, Jul 18, 2012 at 6:12 PM, Yasuaki Ishimatsu
> <isimatu.yasuaki@...fujitsu.com> wrote:
>> The patch adds __remove_pages() to remove_memory(). Then the range of
>> phys_start_pfn argument and nr_pages argument in __remove_pagse() may
>> have different zone. So zone argument is removed from __remove_pages()
>> and __remove_pages() caluculates zone in each section.
>>
>> When CONFIG_SPARSEMEM_VMEMMAP is defined, there is no way to remove a memmap.
>> So __remove_section only calls unregister_memory_section().
>>
>> CC: David Rientjes <rientjes@...gle.com>
>> CC: Jiang Liu <liuj97@...il.com>
>> CC: Len Brown <len.brown@...el.com>
>> CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
>> CC: Paul Mackerras <paulus@...ba.org>
>> CC: Christoph Lameter <cl@...ux.com>
>> Cc: Minchan Kim <minchan.kim@...il.com>
>> CC: Andrew Morton <akpm@...ux-foundation.org>
>> CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
>> CC: Wen Congyang <wency@...fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
>>
>> ---
>> arch/powerpc/platforms/pseries/hotplug-memory.c | 5 +----
>> include/linux/memory_hotplug.h | 3 +--
>> mm/memory_hotplug.c | 19 ++++++++++++-------
>> 3 files changed, 14 insertions(+), 13 deletions(-)
>>
>> Index: linux-3.5-rc6/mm/memory_hotplug.c
>> ===================================================================
>> --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-18 18:00:27.440145432 +0900
>> +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-18 18:01:02.070712487 +0900
>> @@ -275,11 +275,14 @@ static int __meminit __add_section(int n
>> #ifdef CONFIG_SPARSEMEM_VMEMMAP
>> static int __remove_section(struct zone *zone, struct mem_section *ms)
>> {
>> - /*
>> - * XXX: Freeing memmap with vmemmap is not implement yet.
>> - * This should be removed later.
>> - */
>> - return -EBUSY;
>> + int ret = -EINVAL;
>> +
>> + if (!valid_section(ms))
>> + return ret;
>> +
>> + ret = unregister_memory_section(ms);
>> +
>
> I saw a patch from Jiang Liu "mm/hotplug: free zone->pageset when a
> zone becomes empty" to
> free the zone->pageset and i think there may more cleanup needed when
> a zone becomes empty.
>
> We already have __add_zone() in __add_section(), what about add a
> function like __remove_zone()
> to do the cleanup here?
Thank you for your cooment. As you say, I think cleanup function of zone
is necessary. So I'll update it.
Thanks,
Yasuaki Ishimatsu.
>
>> + return ret;
>> }
>> #else
>> static int __remove_section(struct zone *zone, struct mem_section *ms)
>> @@ -346,11 +349,11 @@ EXPORT_SYMBOL_GPL(__add_pages);
>> * sure that pages are marked reserved and zones are adjust properly by
>> * calling offline_pages().
>> */
>> -int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
>> - unsigned long nr_pages)
>> +int __remove_pages(unsigned long phys_start_pfn, unsigned long nr_pages)
>> {
>> unsigned long i, ret = 0;
>> int sections_to_remove;
>> + struct zone *zone;
>>
>> /*
>> * We can only remove entire sections
>> @@ -363,6 +366,7 @@ int __remove_pages(struct zone *zone, un
>> sections_to_remove = nr_pages / PAGES_PER_SECTION;
>> for (i = 0; i < sections_to_remove; i++) {
>> unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
>> + zone = page_zone(pfn_to_page(pfn));
>> ret = __remove_section(zone, __pfn_to_section(pfn));
>> if (ret)
>> break;
>> @@ -1031,6 +1035,7 @@ int __ref remove_memory(int nid, u64 sta
>> /* remove memmap entry */
>> firmware_map_remove(start, start + size, "System RAM");
>>
>> + __remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
>> out:
>> unlock_memory_hotplug();
>> return ret;
>> Index: linux-3.5-rc6/include/linux/memory_hotplug.h
>> ===================================================================
>> --- linux-3.5-rc6.orig/include/linux/memory_hotplug.h 2012-07-18 18:00:27.445145371 +0900
>> +++ linux-3.5-rc6/include/linux/memory_hotplug.h 2012-07-18 18:00:40.461982690 +0900
>> @@ -89,8 +89,7 @@ extern bool is_pageblock_removable_noloc
>> /* reasonably generic interface to expand the physical pages in a zone */
>> extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,
>> unsigned long nr_pages);
>> -extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
>> - unsigned long nr_pages);
>> +extern int __remove_pages(unsigned long start_pfn, unsigned long nr_pages);
>>
>> #ifdef CONFIG_NUMA
>> extern int memory_add_physaddr_to_nid(u64 start);
>> Index: linux-3.5-rc6/arch/powerpc/platforms/pseries/hotplug-memory.c
>> ===================================================================
>> --- linux-3.5-rc6.orig/arch/powerpc/platforms/pseries/hotplug-memory.c 2012-07-18 18:00:27.442145407 +0900
>> +++ linux-3.5-rc6/arch/powerpc/platforms/pseries/hotplug-memory.c 2012-07-18 18:00:40.470982578 +0900
>> @@ -76,7 +76,6 @@ unsigned long memory_block_size_bytes(vo
>> static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
>> {
>> unsigned long start, start_pfn;
>> - struct zone *zone;
>> int i, ret;
>> int sections_to_remove;
>>
>> @@ -87,8 +86,6 @@ static int pseries_remove_memblock(unsig
>> return 0;
>> }
>>
>> - zone = page_zone(pfn_to_page(start_pfn));
>> -
>> /*
>> * Remove section mappings and sysfs entries for the
>> * section of the memory we are removing.
>> @@ -101,7 +98,7 @@ static int pseries_remove_memblock(unsig
>> sections_to_remove = (memblock_size >> PAGE_SHIFT) / PAGES_PER_SECTION;
>> for (i = 0; i < sections_to_remove; i++) {
>> unsigned long pfn = start_pfn + i * PAGES_PER_SECTION;
>> - ret = __remove_pages(zone, start_pfn, PAGES_PER_SECTION);
>> + ret = __remove_pages(start_pfn, PAGES_PER_SECTION);
>> if (ret)
>> return ret;
>> }
>>
>> --
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>> see: http://www.linux-mm.org/ .
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>
>
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