On 2023/5/25 16:24, Mike Rapoport wrote:
> On Thu, May 25, 2023 at 04:01:48AM +0000, Haifeng Xu wrote:
>> Since commit 03e85f9d5f1f ("mm/page_alloc: Introduce free_area_init_core_hotplug"),
>> free_area_init_node() doesn't get called in hotplug path anymore, so
>> remove the comments related to it.
>>
>> Signed-off-by: Haifeng Xu <haifeng.xu@xxxxxxxxxx>
>> ---
>> mm/mm_init.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/mm/mm_init.c b/mm/mm_init.c
>> index 7f7f9c677854..cf55bba04b23 100644
>> --- a/mm/mm_init.c
>> +++ b/mm/mm_init.c
>> @@ -1174,7 +1174,6 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
>> unsigned long zone_start_pfn, zone_end_pfn;
>> unsigned long nr_absent;
>>
>> - /* When hotadd a new node from cpu_up(), the node should be empty */
>> if (!node_start_pfn && !node_end_pfn)
>> return 0;
>
> I think it's better to call calculate_node_totalpages only if node actually has
> memory and for node with no memory we just need to make sure all the node
> and zone page counts are indeed set to 0.
Yes, it's good advice.
>
> Then the condition here and in zone_spanned_pages_in_node() can be removed
> along with the comment and patch 2 won't be required at all.
Regarding to patch 2, if the node has mmeory but contains zone with no memory,
it can avoid the calculation of absent pages.
I thik we can add a check that whether zone_end_pfn is equal to zone_start_pfn
in patch 3. If it's true, return 0 directly. So patch 2 can be dropped.
Thanks!
>
>> @@ -1227,7 +1226,7 @@ static unsigned long __init zone_spanned_pages_in_node(int nid,
>> {
>> unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
>> unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
>> - /* When hotadd a new node from cpu_up(), the node should be empty */
>> +
>> if (!node_start_pfn && !node_end_pfn)
>> return 0;
>>
>> --
>> 2.25.1
>>
>>
>
