mempolicy.h

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/*
 * NUMA memory policies for Linux.
 * Copyright 2003,2004 Andi Kleen SuSE Labs
 */
#ifndef _LINUX_MEMPOLICY_H
#define _LINUX_MEMPOLICY_H 1


#include <linux/mmzone.h>
#include <linux/slab.h>
#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/nodemask.h>
#include <linux/pagemap.h>
#include <uapi/linux/mempolicy.h>

struct mm_struct;

#ifdef CONFIG_NUMA

/*
 * Describe a memory policy.
 *
 * A mempolicy can be either associated with a process or with a VMA.
 * For VMA related allocations the VMA policy is preferred, otherwise
 * the process policy is used. Interrupts ignore the memory policy
 * of the current process.
 *
 * Locking policy for interlave:
 * In process context there is no locking because only the process accesses
 * its own state. All vma manipulation is somewhat protected by a down_read on
 * mmap_sem.
 *
 * Freeing policy:
 * Mempolicy objects are reference counted.  A mempolicy will be freed when
 * mpol_put() decrements the reference count to zero.
 *
 * Duplicating policy objects:
 * mpol_dup() allocates a new mempolicy and copies the specified mempolicy
 * to the new storage.  The reference count of the new object is initialized
 * to 1, representing the caller of mpol_dup().
 */
struct mempolicy {
    atomic_t refcnt;
    unsigned short mode;    /* See MPOL_* above */
    unsigned short flags;   /* See set_mempolicy() MPOL_F_* above */
    union {
        short        preferred_node; /* preferred */
        nodemask_t   nodes;     /* interleave/bind */
        /* undefined for default */
    } v;
    union {
        nodemask_t cpuset_mems_allowed; /* relative to these nodes */
        nodemask_t user_nodemask;   /* nodemask passed by user */
    } w;
};

/*
 * Support for managing mempolicy data objects (clone, copy, destroy)
 * The default fast path of a NULL MPOL_DEFAULT policy is always inlined.
 */

extern void __mpol_put(struct mempolicy *pol);
static inline void mpol_put(struct mempolicy *pol)
{
    if (pol)
        __mpol_put(pol);
}

/*
 * Does mempolicy pol need explicit unref after use?
 * Currently only needed for shared policies.
 */
static inline int mpol_needs_cond_ref(struct mempolicy *pol)
{
    return (pol && (pol->flags & MPOL_F_SHARED));
}

static inline void mpol_cond_put(struct mempolicy *pol)
{
    if (mpol_needs_cond_ref(pol))
        __mpol_put(pol);
}

extern struct mempolicy *__mpol_dup(struct mempolicy *pol);
static inline struct mempolicy *mpol_dup(struct mempolicy *pol)
{
    if (pol)
        pol = __mpol_dup(pol);
    return pol;
}

#define vma_policy(vma) ((vma)->vm_policy)
#define vma_set_policy(vma, pol) ((vma)->vm_policy = (pol))

static inline void mpol_get(struct mempolicy *pol)
{
    if (pol)
        atomic_inc(&pol->refcnt);
}

extern bool __mpol_equal(struct mempolicy *a, struct mempolicy *b);
static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b)
{
    if (a == b)
        return true;
    return __mpol_equal(a, b);
}

/*
 * Tree of shared policies for a shared memory region.
 * Maintain the policies in a pseudo mm that contains vmas. The vmas
 * carry the policy. As a special twist the pseudo mm is indexed in pages, not
 * bytes, so that we can work with shared memory segments bigger than
 * unsigned long.
 */

struct sp_node {
    struct rb_node nd;
    unsigned long start, end;
    struct mempolicy *policy;
};

struct shared_policy {
    struct rb_root root;
    struct mutex mutex;
};

void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol);
int mpol_set_shared_policy(struct shared_policy *info,
                struct vm_area_struct *vma,
                struct mempolicy *new);
void mpol_free_shared_policy(struct shared_policy *p);
struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp,
                        unsigned long idx);

struct mempolicy *get_vma_policy(struct task_struct *tsk,
        struct vm_area_struct *vma, unsigned long addr);

extern void numa_default_policy(void);
extern void numa_policy_init(void);
extern void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new,
                enum mpol_rebind_step step);
extern void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new);
extern void mpol_fix_fork_child_flag(struct task_struct *p);

extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
                unsigned long addr, gfp_t gfp_flags,
                struct mempolicy **mpol, nodemask_t **nodemask);
extern bool init_nodemask_of_mempolicy(nodemask_t *mask);
extern bool mempolicy_nodemask_intersects(struct task_struct *tsk,
                const nodemask_t *mask);
extern unsigned slab_node(void);

extern enum zone_type policy_zone;

static inline void check_highest_zone(enum zone_type k)
{
    if (k > policy_zone && k != ZONE_MOVABLE)
        policy_zone = k;
}

int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
             const nodemask_t *to, int flags);


#ifdef CONFIG_TMPFS
extern int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context);
#endif

extern int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol,
            int no_context);

/* Check if a vma is migratable */
static inline int vma_migratable(struct vm_area_struct *vma)
{
    if (vma->vm_flags & (VM_IO | VM_HUGETLB | VM_PFNMAP))
        return 0;
    /*
     * Migration allocates pages in the highest zone. If we cannot
     * do so then migration (at least from node to node) is not
     * possible.
     */
    if (vma->vm_file &&
        gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
                                < policy_zone)
            return 0;
    return 1;
}

#else

struct mempolicy {};

static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b)
{
    return true;
}

static inline void mpol_put(struct mempolicy *p)
{
}

static inline void mpol_cond_put(struct mempolicy *pol)
{
}

static inline void mpol_get(struct mempolicy *pol)
{
}

static inline struct mempolicy *mpol_dup(struct mempolicy *old)
{
    return NULL;
}

struct shared_policy {};

static inline int mpol_set_shared_policy(struct shared_policy *info,
                    struct vm_area_struct *vma,
                    struct mempolicy *new)
{
    return -EINVAL;
}

static inline void mpol_shared_policy_init(struct shared_policy *sp,
                        struct mempolicy *mpol)
{
}

static inline void mpol_free_shared_policy(struct shared_policy *p)
{
}

static inline struct mempolicy *
mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
{
    return NULL;
}

#define vma_policy(vma) NULL
#define vma_set_policy(vma, pol) do {} while(0)

static inline void numa_policy_init(void)
{
}

static inline void numa_default_policy(void)
{
}

static inline void mpol_rebind_task(struct task_struct *tsk,
                const nodemask_t *new,
                enum mpol_rebind_step step)
{
}

static inline void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
{
}

static inline void mpol_fix_fork_child_flag(struct task_struct *p)
{
}

static inline struct zonelist *huge_zonelist(struct vm_area_struct *vma,
                unsigned long addr, gfp_t gfp_flags,
                struct mempolicy **mpol, nodemask_t **nodemask)
{
    *mpol = NULL;
    *nodemask = NULL;
    return node_zonelist(0, gfp_flags);
}

static inline bool init_nodemask_of_mempolicy(nodemask_t *m)
{
    return false;
}

static inline bool mempolicy_nodemask_intersects(struct task_struct *tsk,
            const nodemask_t *mask)
{
    return false;
}

static inline int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
                   const nodemask_t *to, int flags)
{
    return 0;
}

static inline void check_highest_zone(int k)
{
}

#ifdef CONFIG_TMPFS
static inline int mpol_parse_str(char *str, struct mempolicy **mpol,
                int no_context)
{
    return 1;   /* error */
}
#endif

static inline int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol,
                int no_context)
{
    return 0;
}

#endif /* CONFIG_NUMA */
#endif