Commit 7efecffb authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: remove mlock_vma_page() 

All callers now have a folio and can call mlock_vma_folio().  Update the
documentation to refer to mlock_vma_folio().

Link: https://lkml.kernel.org/r/20230116192827.2146732-3-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 90c9d13a

Documentation/mm/unevictable-lru.rst

+3 −3
Original line number Diff line number Diff line
@@ -311,7 +311,7 @@ do end up getting faulted into this VM_LOCKED VMA, they will be handled in the 
fault path - which is also how mlock2()'s MLOCK_ONFAULT areas are handled.



For each PTE (or PMD) being faulted into a VMA, the page add rmap function

calls mlock_vma_page(), which calls mlock_folio() when the VMA is VM_LOCKED

calls mlock_vma_folio(), which calls mlock_folio() when the VMA is VM_LOCKED

(unless it is a PTE mapping of a part of a transparent huge page).  Or when

it is a newly allocated anonymous page, folio_add_lru_vma() calls

mlock_new_folio() instead: similar to mlock_folio(), but can make better
@@ -413,7 +413,7 @@ However, since mlock_vma_pages_range() starts by setting VM_LOCKED on a VMA, 
before mlocking any pages already present, if one of those pages were migrated

before mlock_pte_range() reached it, it would get counted twice in mlock_count.

To prevent that, mlock_vma_pages_range() temporarily marks the VMA as VM_IO,

so that mlock_vma_page() will skip it.

so that mlock_vma_folio() will skip it.



To complete page migration, we place the old and new pages back onto the LRU

afterwards.  The "unneeded" page - old page on success, new page on failure -
@@ -552,6 +552,6 @@ and node unevictable list. 


rmap's folio_referenced_one(), called via vmscan's shrink_active_list() or

shrink_page_list(), and rmap's try_to_unmap_one() called via shrink_page_list(),

check for (3) pages still mapped into VM_LOCKED VMAs, and call mlock_vma_page()

check for (3) pages still mapped into VM_LOCKED VMAs, and call mlock_vma_folio()

to correct them.  Such pages are culled to the unevictable list when released

by the shrinker.

mm/internal.h

+1 −9
Original line number Diff line number Diff line
@@ -518,7 +518,7 @@ extern long faultin_vma_page_range(struct vm_area_struct *vma, 
extern int mlock_future_check(struct mm_struct *mm, unsigned long flags,

			      unsigned long len);

/*

 * mlock_vma_page() and munlock_vma_page():

 * mlock_vma_folio() and munlock_vma_folio():

 * should be called with vma's mmap_lock held for read or write,

 * under page table lock for the pte/pmd being added or removed.

 *
@@ -547,12 +547,6 @@ static inline void mlock_vma_folio(struct folio *folio, 
		mlock_folio(folio);

}



static inline void mlock_vma_page(struct page *page,

			struct vm_area_struct *vma, bool compound)

{

	mlock_vma_folio(page_folio(page), vma, compound);

}



void munlock_folio(struct folio *folio);



static inline void munlock_vma_folio(struct folio *folio,
@@ -656,8 +650,6 @@ static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf, 
}

#else /* !CONFIG_MMU */

static inline void unmap_mapping_folio(struct folio *folio) { }

static inline void mlock_vma_page(struct page *page,

			struct vm_area_struct *vma, bool compound) { }

static inline void munlock_vma_page(struct page *page,

			struct vm_area_struct *vma, bool compound) { }

static inline void mlock_new_folio(struct folio *folio) { }

mm/mlock.c

+2 −2
Original line number Diff line number Diff line
@@ -370,9 +370,9 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, 
	/*

	 * There is a slight chance that concurrent page migration,

	 * or page reclaim finding a page of this now-VM_LOCKED vma,

	 * will call mlock_vma_page() and raise page's mlock_count:

	 * will call mlock_vma_folio() and raise page's mlock_count:

	 * double counting, leaving the page unevictable indefinitely.

	 * Communicate this danger to mlock_vma_page() with VM_IO,

	 * Communicate this danger to mlock_vma_folio() with VM_IO,

	 * which is a VM_SPECIAL flag not allowed on VM_LOCKED vmas.

	 * mmap_lock is held in write mode here, so this weird

	 * combination should not be visible to other mmap_lock users;

mm/rmap.c

+2 −2
Original line number Diff line number Diff line
@@ -1260,7 +1260,7 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma, 
			__page_check_anon_rmap(page, vma, address);

	}



	mlock_vma_page(page, vma, compound);

	mlock_vma_folio(folio, vma, compound);

}



/**
@@ -1351,7 +1351,7 @@ void page_add_file_rmap(struct page *page, struct vm_area_struct *vma, 
	if (nr)

		__lruvec_stat_mod_folio(folio, NR_FILE_MAPPED, nr);



	mlock_vma_page(page, vma, compound);

	mlock_vma_folio(folio, vma, compound);

}



/**