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nommu: there is no mlock() for NOMMU, so don't provide the bits

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The mlock() facility does not exist for NOMMU since all mappings are
effectively locked anyway, so we don't make the bits available when
they're not useful.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Enrik Berkhan <Enrik.Berkhan@ge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells 2009-03-31 15:23:26 -07:00 committed by Linus Torvalds
parent 7ca43e7564
commit 33925b25d2
3 changed files with 30 additions and 14 deletions
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28
include/linux/page-flags.h
View File

@ -96,6 +96,8 @@ enum pageflags {
PG_swapbacked, /* Page is backed by RAM/swap */
#ifdef CONFIG_UNEVICTABLE_LRU
PG_unevictable, /* Page is "unevictable" */
#endif
#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
PG_mlocked, /* Page is vma mlocked */
#endif
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
@ -234,22 +236,22 @@ PAGEFLAG_FALSE(SwapCache)
#ifdef CONFIG_UNEVICTABLE_LRU
PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
TESTCLEARFLAG(Unevictable, unevictable)
#define MLOCK_PAGES 1
PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
TESTSCFLAG(Mlocked, mlocked)
#else
#define MLOCK_PAGES 0
PAGEFLAG_FALSE(Mlocked)
SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked)
PAGEFLAG_FALSE(Unevictable) TESTCLEARFLAG_FALSE(Unevictable)
SETPAGEFLAG_NOOP(Unevictable) CLEARPAGEFLAG_NOOP(Unevictable)
__CLEARPAGEFLAG_NOOP(Unevictable)
#endif
#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
#define MLOCK_PAGES 1
PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
TESTSCFLAG(Mlocked, mlocked)
#else
#define MLOCK_PAGES 0
PAGEFLAG_FALSE(Mlocked)
SETPAGEFLAG_NOOP(Mlocked) TESTCLEARFLAG_FALSE(Mlocked)
#endif
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PAGEFLAG(Uncached, uncached)
#else
@ -367,9 +369,13 @@ static inline void __ClearPageTail(struct page *page)
#ifdef CONFIG_UNEVICTABLE_LRU
#define __PG_UNEVICTABLE (1 << PG_unevictable)
#define __PG_MLOCKED (1 << PG_mlocked)
#else
#define __PG_UNEVICTABLE 0
#endif
#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
#define __PG_MLOCKED (1 << PG_mlocked)
#else
#define __PG_MLOCKED 0
#endif

8
mm/Kconfig
View File

@ -214,5 +214,13 @@ config UNEVICTABLE_LRU
will use one page flag and increase the code size a little,
say Y unless you know what you are doing.
config HAVE_MLOCK
bool
default y if MMU=y
config HAVE_MLOCKED_PAGE_BIT
bool
default y if HAVE_MLOCK=y && UNEVICTABLE_LRU=y
config MMU_NOTIFIER
bool

8
mm/internal.h
View File

@ -63,6 +63,7 @@ static inline unsigned long page_order(struct page *page)
return page_private(page);
}
#ifdef CONFIG_HAVE_MLOCK
extern long mlock_vma_pages_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
extern void munlock_vma_pages_range(struct vm_area_struct *vma,
@ -71,6 +72,7 @@ static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
{
munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
}
#endif
#ifdef CONFIG_UNEVICTABLE_LRU
/*
@ -90,7 +92,7 @@ static inline void unevictable_migrate_page(struct page *new, struct page *old)
}
#endif
#ifdef CONFIG_UNEVICTABLE_LRU
#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
/*
* Called only in fault path via page_evictable() for a new page
* to determine if it's being mapped into a LOCKED vma.
@ -165,7 +167,7 @@ static inline void free_page_mlock(struct page *page)
}
}
#else /* CONFIG_UNEVICTABLE_LRU */
#else /* CONFIG_HAVE_MLOCKED_PAGE_BIT */
static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
{
return 0;
@ -175,7 +177,7 @@ 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 */
#endif /* CONFIG_HAVE_MLOCKED_PAGE_BIT */
/*
* Return the mem_map entry representing the 'offset' subpage within