From e0650a41f7d024b72669a2a2db846ef70281abd8 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox (Oracle) Date: Mon, 16 Jan 2023 19:28:27 +0000 Subject: mm: clean up mlock_page / munlock_page references in comments Change documentation and comments that refer to now-renamed functions. Link: https://lkml.kernel.org/r/20230116192827.2146732-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- Documentation/mm/unevictable-lru.rst | 30 ++++++++++++++++-------------- mm/memory-failure.c | 2 +- mm/swap.c | 4 ++-- 3 files changed, 19 insertions(+), 17 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. diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ba0bbfc074ee..38f84bff8bdf 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2167,7 +2167,7 @@ try_again: } /* - * __munlock_pagevec may clear a writeback page's LRU flag without + * __munlock_folio() may clear a writeback page's LRU flag without * page_lock. We need wait writeback completion for this page or it * may trigger vfs BUG while evict inode. */ diff --git a/mm/swap.c b/mm/swap.c index 5e4f92700c16..2a51faa34e64 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -201,7 +201,7 @@ static void lru_add_fn(struct lruvec *lruvec, struct folio *folio) * Is an smp_mb__after_atomic() still required here, before * folio_evictable() tests the mlocked flag, to rule out the possibility * of stranding an evictable folio on an unevictable LRU? I think - * not, because __munlock_page() only clears the mlocked flag + * not, because __munlock_folio() only clears the mlocked flag * while the LRU lock is held. * * (That is not true of __page_cache_release(), and not necessarily @@ -216,7 +216,7 @@ static void lru_add_fn(struct lruvec *lruvec, struct folio *folio) folio_set_unevictable(folio); /* * folio->mlock_count = !!folio_test_mlocked(folio)? - * But that leaves __mlock_page() in doubt whether another + * But that leaves __mlock_folio() in doubt whether another * actor has already counted the mlock or not. Err on the * safe side, underestimate, let page reclaim fix it, rather * than leaving a page on the unevictable LRU indefinitely. -- cgit v1.2.3