Re: [PATCH] mm/memory_hotplug: use helper function zone_end_pfn() to get end_pfn
From: Miaohe Lin
Date: Wed Jan 27 2021 - 20:59:52 EST
Hi:
On 2021/1/27 17:40, David Hildenbrand wrote:
> On 27.01.21 10:32, Miaohe Lin wrote:
>> Commit 108bcc96ef70 ("mm: add & use zone_end_pfn() and zone_spans_pfn()")
>> introduced the helper zone_end_pfn() to calculate the zone end pfn. But
>> update_pgdat_span() forgot to use it. Use this helper and re-name local
>> variable zone_end_pfn to end_pfn to fix below compilation error:
>>
>> mm/memory_hotplug.c: In function ‘update_pgdat_span’:
>> mm/memory_hotplug.c:448:32: error: called object ‘zone_end_pfn’ is not a
>> function or function pointer
>> unsigned long zone_end_pfn = zone_end_pfn(zone);
>> ^~~~~~~~~~~~
>> mm/memory_hotplug.c:448:17: note: declared here
>> unsigned long zone_end_pfn = zone_end_pfn(zone);
>> ^~~~~~~~~~~~
>>
>
> Please don't talk about compilation issues your changes introduce in that detail, that's just confusing and looks like something would already be broken. Please simplify to something like
I will keep this in mind. Thanks.
>
> "Let's use zone_end_pfn(zone). We have to rename the local variable to avoid an identifier clash (variable vs. function)."
>
> With that
>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
>
Many thanks for review and reply.
>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>> ---
>> mm/memory_hotplug.c | 9 ++++-----
>> 1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 710e469fb3a1..0483db52b85f 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -493,20 +493,19 @@ static void update_pgdat_span(struct pglist_data *pgdat)
>> for (zone = pgdat->node_zones;
>> zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
>> - unsigned long zone_end_pfn = zone->zone_start_pfn +
>> - zone->spanned_pages;
>> + unsigned long end_pfn = zone_end_pfn(zone);
>> /* No need to lock the zones, they can't change. */
>> if (!zone->spanned_pages)
>> continue;
>> if (!node_end_pfn) {
>> node_start_pfn = zone->zone_start_pfn;
>> - node_end_pfn = zone_end_pfn;
>> + node_end_pfn = end_pfn;
>> continue;
>> }
>> - if (zone_end_pfn > node_end_pfn)
>> - node_end_pfn = zone_end_pfn;
>> + if (end_pfn > node_end_pfn)
>> + node_end_pfn = end_pfn;
>> if (zone->zone_start_pfn < node_start_pfn)
>> node_start_pfn = zone->zone_start_pfn;
>> }
>>
>
>