On Wed, Mar 06, 2024 at 10:52:19PM +1300, Barry Song wrote: > if (folio_test_pmd_mappable(folio)) > flags |= TTU_SPLIT_HUGE_PMD; > + /* > + * Without TTU_SYNC, try_to_unmap will only begin to hold PTL > + * from the first present PTE within a large folio. Some initial > + * PTEs might be skipped due to races with parallel PTE writes > + * in which PTEs can be cleared temporarily before being written > + * new present values. This will lead to a large folio is still > + * mapped while some subpages have been partially unmapped after > + * try_to_unmap; TTU_SYNC helps try_to_unmap acquire PTL from the > + * first PTE, eliminating the influence of temporary PTE values. > + */ Please wrap comments at <80 columns. The easiest way to do this is just to pipe the block of text through "fmt -p \*" (need to quote the * to prevent it from being a glob/regex)
