diff options
Diffstat (limited to 'Documentation/mm')
| -rw-r--r-- | Documentation/mm/unevictable-lru.rst | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/Documentation/mm/unevictable-lru.rst b/Documentation/mm/unevictable-lru.rst index 34b8b098c5bc..53e59433497a 100644 --- a/Documentation/mm/unevictable-lru.rst +++ b/Documentation/mm/unevictable-lru.rst @@ -298,7 +298,7 @@ treated as a no-op and mlock_fixup() simply returns. If the VMA passes some filtering as described in "Filtering Special VMAs" below, mlock_fixup() will attempt to merge the VMA with its neighbors or split off a subset of the VMA if the range does not cover the entire VMA. Any pages -already present in the VMA are then marked as mlocked by mlock_page() via +already present in the VMA are then marked as mlocked by mlock_folio() via mlock_pte_range() via walk_page_range() via mlock_vma_pages_range(). Before returning from the system call, do_mlock() or mlockall() will call @@ -373,20 +373,21 @@ Because of the VMA filtering discussed above, VM_LOCKED will not be set in any "special" VMAs. So, those VMAs will be ignored for munlock. If the VMA is VM_LOCKED, mlock_fixup() again attempts to merge or split off the -specified range. All pages in the VMA are then munlocked by munlock_page() via +specified range. All pages in the VMA are then munlocked by munlock_folio() via mlock_pte_range() via walk_page_range() via mlock_vma_pages_range() - the same function used when mlocking a VMA range, with new flags for the VMA indicating that it is munlock() being performed. -munlock_page() uses the mlock pagevec to batch up work to be done under -lru_lock by __munlock_page(). __munlock_page() decrements the page's -mlock_count, and when that reaches 0 it clears PG_mlocked and clears -PG_unevictable, moving the page from unevictable state to inactive LRU. +munlock_folio() uses the mlock pagevec to batch up work to be done +under lru_lock by __munlock_folio(). __munlock_folio() decrements the +folio's mlock_count, and when that reaches 0 it clears the mlocked flag +and clears the unevictable flag, moving the folio from unevictable state +to the inactive LRU. -But in practice that may not work ideally: the page may not yet have reached +But in practice that may not work ideally: the folio may not yet have reached "the unevictable LRU", or it may have been temporarily isolated from it. In those cases its mlock_count field is unusable and must be assumed to be 0: so -that the page will be rescued to an evictable LRU, then perhaps be mlocked +that the folio will be rescued to an evictable LRU, then perhaps be mlocked again later if vmscan finds it in a VM_LOCKED VMA. @@ -489,15 +490,16 @@ For each PTE (or PMD) being unmapped from a VMA, page_remove_rmap() calls munlock_vma_folio(), which calls munlock_folio() when the VMA is VM_LOCKED (unless it was a PTE mapping of a part of a transparent huge page). -munlock_page() uses the mlock pagevec to batch up work to be done under -lru_lock by __munlock_page(). __munlock_page() decrements the page's -mlock_count, and when that reaches 0 it clears PG_mlocked and clears -PG_unevictable, moving the page from unevictable state to inactive LRU. +munlock_folio() uses the mlock pagevec to batch up work to be done +under lru_lock by __munlock_folio(). __munlock_folio() decrements the +folio's mlock_count, and when that reaches 0 it clears the mlocked flag +and clears the unevictable flag, moving the folio from unevictable state +to the inactive LRU. -But in practice that may not work ideally: the page may not yet have reached +But in practice that may not work ideally: the folio may not yet have reached "the unevictable LRU", or it may have been temporarily isolated from it. In those cases its mlock_count field is unusable and must be assumed to be 0: so -that the page will be rescued to an evictable LRU, then perhaps be mlocked +that the folio will be rescued to an evictable LRU, then perhaps be mlocked again later if vmscan finds it in a VM_LOCKED VMA. |