80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
|
#ifndef __LINUX_KSM_H
|
||
|
|
#define __LINUX_KSM_H
|
||
|
|
/*
|
||
|
|
* Memory merging support.
|
||
|
|
*
|
||
|
|
* This code enables dynamic sharing of identical pages found in different
|
||
|
|
* memory areas, even if they are not shared by fork().
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/bitops.h>
|
||
|
|
#include <linux/mm.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/vmstat.h>
|
||
|
|
|
||
|
|
#ifdef CONFIG_KSM
|
||
|
|
int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
|
||
|
|
unsigned long end, int advice, unsigned long *vm_flags);
|
||
|
|
int __ksm_enter(struct mm_struct *mm);
|
||
|
|
void __ksm_exit(struct mm_struct *mm);
|
||
|
|
|
||
|
|
static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
|
||
|
|
{
|
||
|
|
if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags))
|
||
|
|
return __ksm_enter(mm);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void ksm_exit(struct mm_struct *mm)
|
||
|
|
{
|
||
|
|
if (test_bit(MMF_VM_MERGEABLE, &mm->flags))
|
||
|
|
__ksm_exit(mm);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* A KSM page is one of those write-protected "shared pages" or "merged pages"
|
||
|
|
* which KSM maps into multiple mms, wherever identical anonymous page content
|
||
|
|
* is found in VM_MERGEABLE vmas. It's a PageAnon page, with NULL anon_vma.
|
||
|
|
*/
|
||
|
|
static inline int PageKsm(struct page *page)
|
||
|
|
{
|
||
|
|
return ((unsigned long)page->mapping == PAGE_MAPPING_ANON);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* But we have to avoid the checking which page_add_anon_rmap() performs.
|
||
|
|
*/
|
||
|
|
static inline void page_add_ksm_rmap(struct page *page)
|
||
|
|
{
|
||
|
|
if (atomic_inc_and_test(&page->_mapcount)) {
|
||
|
|
page->mapping = (void *) PAGE_MAPPING_ANON;
|
||
|
|
__inc_zone_page_state(page, NR_ANON_PAGES);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
#else /* !CONFIG_KSM */
|
||
|
|
|
||
|
|
static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
|
||
|
|
unsigned long end, int advice, unsigned long *vm_flags)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void ksm_exit(struct mm_struct *mm)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline int PageKsm(struct page *page)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* No stub required for page_add_ksm_rmap(page) */
|
||
|
|
#endif /* !CONFIG_KSM */
|
||
|
|
|
||
|
|
#endif
|