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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165/* 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>
#ifdef CONFIG_KSMint ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, vm_flags_t *vm_flags);vma_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vma_flags_t vma_flags);int ksm_enable_merge_any(struct mm_struct *mm);int ksm_disable_merge_any(struct mm_struct *mm);int ksm_disable(struct mm_struct *mm);
int __ksm_enter(struct mm_struct *mm);void __ksm_exit(struct mm_struct *mm);/* * To identify zeropages that were mapped by KSM, we reuse the dirty bit * in the PTE. If the PTE is dirty, the zeropage was mapped by KSM when * deduplicating memory. */#define is_ksm_zero_pte(pte) (is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte))
extern atomic_long_t ksm_zero_pages;
static inline void ksm_map_zero_page(struct mm_struct *mm){ atomic_long_inc(&ksm_zero_pages); atomic_long_inc(&mm->ksm_zero_pages);}
static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte){ if (is_ksm_zero_pte(pte)) { atomic_long_dec(&ksm_zero_pages); atomic_long_dec(&mm->ksm_zero_pages); }}
static inline long mm_ksm_zero_pages(struct mm_struct *mm){ return atomic_long_read(&mm->ksm_zero_pages);}
static inline void ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm){ /* Adding mm to ksm is best effort on fork. */ if (mm_flags_test(MMF_VM_MERGEABLE, oldmm)) { long nr_ksm_zero_pages = atomic_long_read(&mm->ksm_zero_pages);
mm->ksm_merging_pages = 0; mm->ksm_rmap_items = 0; atomic_long_add(nr_ksm_zero_pages, &ksm_zero_pages); __ksm_enter(mm); }}
static inline int ksm_execve(struct mm_struct *mm){ if (mm_flags_test(MMF_VM_MERGE_ANY, mm)) return __ksm_enter(mm);
return 0;}
static inline void ksm_exit(struct mm_struct *mm){ if (mm_flags_test(MMF_VM_MERGEABLE, mm)) __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 folio *ksm_might_need_to_copy(struct folio *folio, struct vm_area_struct *vma, unsigned long addr);
void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);void collect_procs_ksm(const struct folio *folio, const struct page *page, struct list_head *to_kill, int force_early);long ksm_process_profit(struct mm_struct *);bool ksm_process_mergeable(struct mm_struct *mm);
#else /* !CONFIG_KSM */
static inline vma_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, vma_flags_t vma_flags){ return vma_flags;}
static inline int ksm_disable(struct mm_struct *mm){ return 0;}
static inline void ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm){}
static inline int ksm_execve(struct mm_struct *mm){ return 0;}
static inline void ksm_exit(struct mm_struct *mm){}
static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte){}
static inline void collect_procs_ksm(const struct folio *folio, const struct page *page, struct list_head *to_kill, int force_early){}
#ifdef CONFIG_MMUstatic inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, vm_flags_t *vm_flags){ return 0;}
static inline struct folio *ksm_might_need_to_copy(struct folio *folio, struct vm_area_struct *vma, unsigned long addr){ return folio;}
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 */