90 lines
2.4 KiB
C
90 lines
2.4 KiB
C
|
/* SPDX-License-Identifier: GPL-2.0 */
|
||
|
|
#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/pagemap.h>
|
||
|
|
#include <linux/rmap.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/sched/coredump.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);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* When do_swap_page() first faults in from swap what used to be a KSM page,
|
||
|
|
* no problem, it will be assigned to this vma's anon_vma; but thereafter,
|
||
|
|
* it might be faulted into a different anon_vma (or perhaps to a different
|
||
|
|
* offset in the same anon_vma). do_swap_page() cannot do all the locking
|
||
|
|
* needed to reconstitute a cross-anon_vma KSM page: for now it has to make
|
||
|
|
* a copy, and leave remerging the pages to a later pass of ksmd.
|
||
|
|
*
|
||
|
|
* We'd like to make this conditional on vma->vm_flags & VM_MERGEABLE,
|
||
|
|
* but what if the vma was unmerged while the page was swapped out?
|
||
|
|
*/
|
||
|
|
struct page *ksm_might_need_to_copy(struct page *page,
|
||
|
|
struct vm_area_struct *vma, unsigned long address);
|
||
|
|
|
||
|
|
void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);
|
||
|
|
void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);
|
||
|
|
|
||
|
|
#else /* !CONFIG_KSM */
|
||
|
|
|
||
|
|
static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void ksm_exit(struct mm_struct *mm)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef CONFIG_MMU
|
||
|
|
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 struct page *ksm_might_need_to_copy(struct page *page,
|
||
|
|
struct vm_area_struct *vma, unsigned long address)
|
||
|
|
{
|
||
|
|
return page;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void rmap_walk_ksm(struct folio *folio,
|
||
|
|
struct rmap_walk_control *rwc)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void folio_migrate_ksm(struct folio *newfolio, struct folio *old)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
#endif /* CONFIG_MMU */
|
||
|
|
#endif /* !CONFIG_KSM */
|
||
|
|
|
||
|
|
#endif /* __LINUX_KSM_H */
|