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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - include/linux/sched/mm.h
1 #ifndef _LINUX_SCHED_MM_H
2 #define _LINUX_SCHED_MM_H
4 #include <linux/kernel.h>
5 #include <linux/atomic.h>
6 #include <linux/sched.h>
7 #include <linux/mm_types.h>
11 * Routines for handling mm_structs
13 extern struct mm_struct
* mm_alloc(void);
16 * mmgrab() - Pin a &struct mm_struct.
17 * @mm: The &struct mm_struct to pin.
19 * Make sure that @mm will not get freed even after the owning task
20 * exits. This doesn't guarantee that the associated address space
21 * will still exist later on and mmget_not_zero() has to be used before
24 * This is a preferred way to to pin @mm for a longer/unbounded amount
27 * Use mmdrop() to release the reference acquired by mmgrab().
29 * See also <Documentation/vm/active_mm.txt> for an in-depth explanation
30 * of &mm_struct.mm_count vs &mm_struct.mm_users.
32 static inline void mmgrab(struct mm_struct
*mm
)
34 atomic_inc(&mm
->mm_count
);
37 /* mmdrop drops the mm and the page tables */
38 extern void __mmdrop(struct mm_struct
*);
39 static inline void mmdrop(struct mm_struct
*mm
)
41 if (unlikely(atomic_dec_and_test(&mm
->mm_count
)))
45 static inline void mmdrop_async_fn(struct work_struct
*work
)
47 struct mm_struct
*mm
= container_of(work
, struct mm_struct
, async_put_work
);
51 static inline void mmdrop_async(struct mm_struct
*mm
)
53 if (unlikely(atomic_dec_and_test(&mm
->mm_count
))) {
54 INIT_WORK(&mm
->async_put_work
, mmdrop_async_fn
);
55 schedule_work(&mm
->async_put_work
);
60 * mmget() - Pin the address space associated with a &struct mm_struct.
61 * @mm: The address space to pin.
63 * Make sure that the address space of the given &struct mm_struct doesn't
64 * go away. This does not protect against parts of the address space being
65 * modified or freed, however.
67 * Never use this function to pin this address space for an
68 * unbounded/indefinite amount of time.
70 * Use mmput() to release the reference acquired by mmget().
72 * See also <Documentation/vm/active_mm.txt> for an in-depth explanation
73 * of &mm_struct.mm_count vs &mm_struct.mm_users.
75 static inline void mmget(struct mm_struct
*mm
)
77 atomic_inc(&mm
->mm_users
);
80 static inline bool mmget_not_zero(struct mm_struct
*mm
)
82 return atomic_inc_not_zero(&mm
->mm_users
);
85 /* mmput gets rid of the mappings and all user-space */
86 extern void mmput(struct mm_struct
*);
88 /* same as above but performs the slow path from the async context. Can
89 * be called from the atomic context as well
91 extern void mmput_async(struct mm_struct
*);
94 /* Grab a reference to a task's mm, if it is not already going away */
95 extern struct mm_struct
*get_task_mm(struct task_struct
*task
);
97 * Grab a reference to a task's mm, if it is not already going away
98 * and ptrace_may_access with the mode parameter passed to it
101 extern struct mm_struct
*mm_access(struct task_struct
*task
, unsigned int mode
);
102 /* Remove the current tasks stale references to the old mm_struct */
103 extern void mm_release(struct task_struct
*, struct mm_struct
*);
106 extern void mm_update_next_owner(struct mm_struct
*mm
);
108 static inline void mm_update_next_owner(struct mm_struct
*mm
)
111 #endif /* CONFIG_MEMCG */
114 extern void arch_pick_mmap_layout(struct mm_struct
*mm
);
116 arch_get_unmapped_area(struct file
*, unsigned long, unsigned long,
117 unsigned long, unsigned long);
119 arch_get_unmapped_area_topdown(struct file
*filp
, unsigned long addr
,
120 unsigned long len
, unsigned long pgoff
,
121 unsigned long flags
);
123 static inline void arch_pick_mmap_layout(struct mm_struct
*mm
) {}
126 static inline bool in_vfork(struct task_struct
*tsk
)
131 * need RCU to access ->real_parent if CLONE_VM was used along with
134 * We check real_parent->mm == tsk->mm because CLONE_VFORK does not
137 * CLONE_VFORK can be used with CLONE_PARENT/CLONE_THREAD and thus
138 * ->real_parent is not necessarily the task doing vfork(), so in
139 * theory we can't rely on task_lock() if we want to dereference it.
141 * And in this case we can't trust the real_parent->mm == tsk->mm
142 * check, it can be false negative. But we do not care, if init or
143 * another oom-unkillable task does this it should blame itself.
146 ret
= tsk
->vfork_done
&& tsk
->real_parent
->mm
== tsk
->mm
;
153 * Applies per-task gfp context to the given allocation flags.
154 * PF_MEMALLOC_NOIO implies GFP_NOIO
155 * PF_MEMALLOC_NOFS implies GFP_NOFS
157 static inline gfp_t
current_gfp_context(gfp_t flags
)
160 * NOIO implies both NOIO and NOFS and it is a weaker context
161 * so always make sure it makes precendence
163 if (unlikely(current
->flags
& PF_MEMALLOC_NOIO
))
164 flags
&= ~(__GFP_IO
| __GFP_FS
);
165 else if (unlikely(current
->flags
& PF_MEMALLOC_NOFS
))
170 static inline unsigned int memalloc_noio_save(void)
172 unsigned int flags
= current
->flags
& PF_MEMALLOC_NOIO
;
173 current
->flags
|= PF_MEMALLOC_NOIO
;
177 static inline void memalloc_noio_restore(unsigned int flags
)
179 current
->flags
= (current
->flags
& ~PF_MEMALLOC_NOIO
) | flags
;
182 static inline unsigned int memalloc_nofs_save(void)
184 unsigned int flags
= current
->flags
& PF_MEMALLOC_NOFS
;
185 current
->flags
|= PF_MEMALLOC_NOFS
;
189 static inline void memalloc_nofs_restore(unsigned int flags
)
191 current
->flags
= (current
->flags
& ~PF_MEMALLOC_NOFS
) | flags
;
194 static inline unsigned int memalloc_noreclaim_save(void)
196 unsigned int flags
= current
->flags
& PF_MEMALLOC
;
197 current
->flags
|= PF_MEMALLOC
;
201 static inline void memalloc_noreclaim_restore(unsigned int flags
)
203 current
->flags
= (current
->flags
& ~PF_MEMALLOC
) | flags
;
206 #endif /* _LINUX_SCHED_MM_H */