Commit 985737cf authored by Lee Schermerhorn's avatar Lee Schermerhorn Committed by Linus Torvalds
Browse files

mlock: count attempts to free mlocked page 



Allow free of mlock()ed pages.  This shouldn't happen, but during
developement, it occasionally did.

This patch allows us to survive that condition, while keeping the
statistics and events correct for debug.

Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent af936a16

include/linux/vmstat.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 
		UNEVICTABLE_PGMUNLOCKED,

		UNEVICTABLE_PGCLEARED,	/* on COW, page truncate */

		UNEVICTABLE_PGSTRANDED,	/* unable to isolate on unlock */

		UNEVICTABLE_MLOCKFREED,

#endif

		NR_VM_EVENT_ITEMS

};

mm/internal.h

+17 −0
Original line number Diff line number Diff line
@@ -146,6 +146,22 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page) 
	}

}



/*

 * free_page_mlock() -- clean up attempts to free and mlocked() page.

 * Page should not be on lru, so no need to fix that up.

 * free_pages_check() will verify...

 */

static inline void free_page_mlock(struct page *page)

{

	if (unlikely(TestClearPageMlocked(page))) {

		unsigned long flags;



		local_irq_save(flags);

		__dec_zone_page_state(page, NR_MLOCK);

		__count_vm_event(UNEVICTABLE_MLOCKFREED);

		local_irq_restore(flags);

	}

}



#else /* CONFIG_UNEVICTABLE_LRU */

static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
@@ -155,6 +171,7 @@ static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p) 
static inline void clear_page_mlock(struct page *page) { }

static inline void mlock_vma_page(struct page *page) { }

static inline void mlock_migrate_page(struct page *new, struct page *old) { }

static inline void free_page_mlock(struct page *page) { }



#endif /* CONFIG_UNEVICTABLE_LRU */

mm/page_alloc.c

+1 −0
Original line number Diff line number Diff line
@@ -454,6 +454,7 @@ static inline void __free_one_page(struct page *page, 


static inline int free_pages_check(struct page *page)

{

	free_page_mlock(page);

	if (unlikely(page_mapcount(page) |

		(page->mapping != NULL)  |

		(page_get_page_cgroup(page) != NULL) |

mm/vmstat.c

+1 −0
Original line number Diff line number Diff line
@@ -689,6 +689,7 @@ static const char * const vmstat_text[] = { 
	"unevictable_pgs_munlocked",

	"unevictable_pgs_cleared",

	"unevictable_pgs_stranded",

	"unevictable_pgs_mlockfreed",

#endif

#endif

};

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