On 2015/8/23 18:28, Tang Chen wrote:
> Hi Shi,
>
> Sorry for the late reply. I hope it won't be too late.
>
> NON-ACK by me, I think.
>
> I noticed that your first has been merged. But it won't fix the problem
> these code intended to fix.
>
> After your patch 1, zone's spanned/present won't be set to 0 because:
>
> free_area_init_node()
> |--> get_pfn_range_for_nid(&start_pfn, &end_pfn)
> |--> calculate_node_totalpages(pgdat, start_pfn, end_pfn, ...)
> | --> zone_spanned_pages_in_node()
> | --> if (!node_start_pfn && !node_end_pfn) return 0; -------- false, won't return 0
> | --> zone_absent_pages_in_node()
> | --> if (!node_start_pfn && !node_end_pfn) return 0; -------- false, won't return 0
>
Hi Tang,
Thank you for your reply. When we add a new node, it is not included in the
memblock, I have no idea why zone_spanned_pages_in_node() and zone_absent_pages_in_node()
won't return 0. Do you add some debug code and print it?
> This is caused by a little bug in your patch 1.
>
> You should put memblock_add_node(start, size, nid) before hotadd_new_pgdat()
> because:
>
My patch is just add an empty node first, later __add_zone() will update the size.
But it is all right put here, and it can fix the print bug.
> hotadd_new_pgdat()
> | --> free_area_init_node()
> | --> get_pfn_range_for_nid()
> | --> find memory ranges in memblock.
>
> | --> memblock_add_node(start, size, nid) ------------------- if you add it here, it doesn't work.
>
> The result will be like below if we hotadd node 5.
> [ 2007.577000] Initmem setup node 5 [mem 0x0000000000000000-0xffffffffffffffff]
pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
(u64)start_pfn << PAGE_SHIFT, ((u64)end_pfn << PAGE_SHIFT) - 1);
start_pfn and end_pfn are both 0, and 0-1 -> 0xffffffffffffffff, right?
> [ 2007.584000] On node 5 totalpages: 0
> [ 2007.585000] Built 5 zonelists in Node order, mobility grouping on. Total pages: 32588823
> [ 2007.594000] Policy zone: Normal
> [ 2007.598000] init_memory_mapping: [mem 0x60000000000-0x607ffffffff]
>
>
> And also, if we merge this patch, /sys/devices/system/node/nodeX/meminfo will break.
>
trigger call trace?
>
> Since this patch is not merged, I think let's just drop it.
>
> And about the little bug in your patch 1, since I'm in a hurry, I have already send a patch to fix it.
>
>
> Thanks. :)
>
>
> On 08/11/2015 03:33 PM, Xishi Qiu wrote:
>> After hotadd_new_pgdat()->free_area_init_node(), the pgdat and zone's spanned/present
>> are both 0, so remove reset_node_managed_pages() and reset_node_managed_pages().
>>
>> Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
>> ---
>> mm/memory_hotplug.c | 25 -------------------------
>> 1 file changed, 25 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 11f26cc..997dfad 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1065,16 +1065,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
>> }
>> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
>> -static void reset_node_present_pages(pg_data_t *pgdat)
>> -{
>> - struct zone *z;
>> -
>> - for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
>> - z->present_pages = 0;
>> -
>> - pgdat->node_present_pages = 0;
>> -}
>> -
>> /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
>> static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
>> {
>> @@ -1109,21 +1099,6 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
>> build_all_zonelists(pgdat, NULL);
>> mutex_unlock(&zonelists_mutex);
>> - /*
>> - * zone->managed_pages is set to an approximate value in
>> - * free_area_init_core(), which will cause
>> - * /sys/device/system/node/nodeX/meminfo has wrong data.
>> - * So reset it to 0 before any memory is onlined.
>> - */
>> - reset_node_managed_pages(pgdat);
>> -
>> - /*
>> - * When memory is hot-added, all the memory is in offline state. So
>> - * clear all zones' present_pages because they will be updated in
>> - * online_pages() and offline_pages().
>> - */
>> - reset_node_present_pages(pgdat);
>> -
>> return pgdat;
>> }
>>
>
>
> .
>
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