Current File : //usr/src/kernels/3.10.0-957.21.3.el7.centos.plus.x86_64/include/linux/migrate.h
#ifndef _LINUX_MIGRATE_H
#define _LINUX_MIGRATE_H
#include <linux/mm.h>
#include <linux/mempolicy.h>
#include <linux/migrate_mode.h>
typedef struct page *new_page_t(struct page *, unsigned long private, int **);
/*
* Return values from addresss_space_operations.migratepage():
* - negative errno on page migration failure;
* - zero on page migration success;
*/
#define MIGRATEPAGE_SUCCESS 0
enum migrate_reason {
MR_COMPACTION,
MR_MEMORY_FAILURE,
MR_MEMORY_HOTPLUG,
MR_SYSCALL, /* also applies to cpusets */
MR_MEMPOLICY_MBIND,
MR_NUMA_MISPLACED,
MR_CMA
};
#ifdef CONFIG_MIGRATION
extern void putback_lru_pages(struct list_head *l);
extern void putback_movable_pages(struct list_head *l);
extern int migrate_page(struct address_space *,
struct page *, struct page *, enum migrate_mode);
extern int migrate_pages(struct list_head *l, new_page_t x,
unsigned long private, enum migrate_mode mode, int reason);
extern int fail_migrate_page(struct address_space *,
struct page *, struct page *);
extern int migrate_prep(void);
extern int migrate_prep_local(void);
extern int migrate_vmas(struct mm_struct *mm,
const nodemask_t *from, const nodemask_t *to,
unsigned long flags);
extern void migrate_page_copy(struct page *newpage, struct page *page);
extern void migrate_page_states(struct page *newpage, struct page *page);
extern int migrate_huge_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page);
extern int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page,
struct buffer_head *head, enum migrate_mode mode,
int extra_count);
#else
static inline void putback_lru_pages(struct list_head *l) {}
static inline void putback_movable_pages(struct list_head *l) {}
static inline int migrate_pages(struct list_head *l, new_page_t x,
unsigned long private, enum migrate_mode mode, int reason)
{ return -ENOSYS; }
static inline int migrate_prep(void) { return -ENOSYS; }
static inline int migrate_prep_local(void) { return -ENOSYS; }
static inline int migrate_vmas(struct mm_struct *mm,
const nodemask_t *from, const nodemask_t *to,
unsigned long flags)
{
return -ENOSYS;
}
static inline void migrate_page_copy(struct page *newpage,
struct page *page) {}
static inline void migrate_page_states(struct page *newpage, struct page *page)
{
}
static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page)
{
return -ENOSYS;
}
/* Possible settings for the migrate_page() method in address_operations */
#define migrate_page NULL
#define fail_migrate_page NULL
#endif /* CONFIG_MIGRATION */
#ifdef CONFIG_NUMA_BALANCING
extern bool pmd_trans_migrating(pmd_t pmd);
extern int migrate_misplaced_page(struct page *page,
struct vm_area_struct *vma, int node);
extern bool migrate_ratelimited(int node);
#else
static inline bool pmd_trans_migrating(pmd_t pmd)
{
return false;
}
static inline int migrate_misplaced_page(struct page *page,
struct vm_area_struct *vma, int node)
{
return -EAGAIN; /* can't migrate now */
}
static inline bool migrate_ratelimited(int node)
{
return false;
}
#endif /* CONFIG_NUMA_BALANCING */
#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
struct vm_area_struct *vma,
pmd_t *pmd, pmd_t entry,
unsigned long address,
struct page *page, int node);
#else
static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
struct vm_area_struct *vma,
pmd_t *pmd, pmd_t entry,
unsigned long address,
struct page *page, int node)
{
return -EAGAIN;
}
#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
#ifdef CONFIG_MIGRATION
/*
* Watch out for PAE architecture, which has an unsigned long, and might not
* have enough bits to store all physical address and flags. So far we have
* enough room for all our flags.
*/
#define MIGRATE_PFN_VALID (1UL << 0)
#define MIGRATE_PFN_MIGRATE (1UL << 1)
#define MIGRATE_PFN_LOCKED (1UL << 2)
#define MIGRATE_PFN_WRITE (1UL << 3)
#define MIGRATE_PFN_DEVICE (1UL << 4)
#define MIGRATE_PFN_ERROR (1UL << 5)
#define MIGRATE_PFN_SHIFT 6
static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
{
if (!(mpfn & MIGRATE_PFN_VALID))
return NULL;
return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
}
static inline unsigned long migrate_pfn(unsigned long pfn)
{
return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
}
/*
* struct migrate_vma_ops - migrate operation callback
*
* @alloc_and_copy: alloc destination memory and copy source memory to it
* @finalize_and_map: allow caller to map the successfully migrated pages
*
*
* The alloc_and_copy() callback happens once all source pages have been locked,
* unmapped and checked (checked whether pinned or not). All pages that can be
* migrated will have an entry in the src array set with the pfn value of the
* page and with the MIGRATE_PFN_VALID and MIGRATE_PFN_MIGRATE flag set (other
* flags might be set but should be ignored by the callback).
*
* The alloc_and_copy() callback can then allocate destination memory and copy
* source memory to it for all those entries (ie with MIGRATE_PFN_VALID and
* MIGRATE_PFN_MIGRATE flag set). Once these are allocated and copied, the
* callback must update each corresponding entry in the dst array with the pfn
* value of the destination page and with the MIGRATE_PFN_VALID and
* MIGRATE_PFN_LOCKED flags set (destination pages must have their struct pages
* locked, via lock_page()).
*
* At this point the alloc_and_copy() callback is done and returns.
*
* Note that the callback does not have to migrate all the pages that are
* marked with MIGRATE_PFN_MIGRATE flag in src array unless this is a migration
* from device memory to system memory (ie the MIGRATE_PFN_DEVICE flag is also
* set in the src array entry). If the device driver cannot migrate a device
* page back to system memory, then it must set the corresponding dst array
* entry to MIGRATE_PFN_ERROR. This will trigger a SIGBUS if CPU tries to
* access any of the virtual addresses originally backed by this page. Because
* a SIGBUS is such a severe result for the userspace process, the device
* driver should avoid setting MIGRATE_PFN_ERROR unless it is really in an
* unrecoverable state.
*
* THE alloc_and_copy() CALLBACK MUST NOT CHANGE ANY OF THE SRC ARRAY ENTRIES
* OR BAD THINGS WILL HAPPEN !
*
*
* The finalize_and_map() callback happens after struct page migration from
* source to destination (destination struct pages are the struct pages for the
* memory allocated by the alloc_and_copy() callback). Migration can fail, and
* thus the finalize_and_map() allows the driver to inspect which pages were
* successfully migrated, and which were not. Successfully migrated pages will
* have the MIGRATE_PFN_MIGRATE flag set for their src array entry.
*
* It is safe to update device page table from within the finalize_and_map()
* callback because both destination and source page are still locked, and the
* mmap_sem is held in read mode (hence no one can unmap the range being
* migrated).
*
* Once callback is done cleaning up things and updating its page table (if it
* chose to do so, this is not an obligation) then it returns. At this point,
* the HMM core will finish up the final steps, and the migration is complete.
*
* THE finalize_and_map() CALLBACK MUST NOT CHANGE ANY OF THE SRC OR DST ARRAY
* ENTRIES OR BAD THINGS WILL HAPPEN !
*/
struct migrate_vma_ops {
void (*alloc_and_copy)(struct vm_area_struct *vma,
const unsigned long *src,
unsigned long *dst,
unsigned long start,
unsigned long end,
void *private);
void (*finalize_and_map)(struct vm_area_struct *vma,
const unsigned long *src,
const unsigned long *dst,
unsigned long start,
unsigned long end,
void *private);
};
int migrate_vma(const struct migrate_vma_ops *ops,
struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
unsigned long *src,
unsigned long *dst,
void *private);
#endif /* CONFIG_MIGRATION */
#endif /* _LINUX_MIGRATE_H */
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