Re: [PATCH v2] mm: Fix for negative counter: nr_file_hugepages

[Stefan Roesch]

Matthew Wilcox <willy@xxxxxxxxxxxxx> writes:

> On Tue, Nov 07, 2023 at 10:18:05AM -0800, Stefan Roesch wrote:
>> +++ b/mm/huge_memory.c
>> @@ -2740,7 +2740,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
>>  			if (folio_test_swapbacked(folio)) {
>>  				__lruvec_stat_mod_folio(folio, NR_SHMEM_THPS,
>>  							-nr);
>> -			} else {
>> +			} else if (folio_test_pmd_mappable(folio)) {
>>  				__lruvec_stat_mod_folio(folio, NR_FILE_THPS,
>>  							-nr);
>>  				filemap_nr_thps_dec(mapping);
>
> As I said, we also need the folio_test_pmd_mappable() for swapbacked.
> Not because there's currently a problem, but because we don't leave
> landmines for other people to trip over in future!

I'll add it in the next version.