Messages in this thread | | | Date | Mon, 24 Apr 2023 18:46:40 +0800 | Subject | Re: [PATCH v2 1/2] mm/page_alloc: drop the unnecessary pfn_valid() for start pfn | From | Baolin Wang <> |
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On 4/24/2023 5:50 PM, Michal Hocko wrote: > On Sun 23-04-23 18:59:10, Baolin Wang wrote: >> We've already used pfn_to_online_page() for start pfn to make sure > > Who is we? I do not see any note explicitly requiring that start_pfn has > to be valid for __pageblock_pfn_to_page.
Sorry for confusing, what I mean is the __pageblock_pfn_to_page() function, which has used pfn_to_online_page() for start pfn. So the pfn_valid() in __pageblock_pfn_to_page() for start pfn is unnecessary.
I will update the commit log to make it clear.
>> it is online and valid, so the pfn_valid() for the start pfn is >> unnecessary, drop it. >> >> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> >> Reviewed-by: David Hildenbrand <david@redhat.com> >> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> >> --- >> Changes from v1: >> - Collect reviewed tags. Thanks David and Ying. >> --- >> mm/page_alloc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 9de2a18519a1..6457b64fe562 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -1512,7 +1512,7 @@ struct page *__pageblock_pfn_to_page(unsigned long start_pfn, >> /* end_pfn is one past the range we are checking */ >> end_pfn--; >> >> - if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn)) >> + if (!pfn_valid(end_pfn)) >> return NULL; >> >> start_page = pfn_to_online_page(start_pfn); >> -- >> 2.27.0 >
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