1 /* SPDX-License-Identifier: GPL-2.0 */
18  * mmgrab() - Pin a &struct mm_struct.
31  * See also <Documentation/mm/active_mm.rst> for an in-depth explanation
36 	atomic_inc(&mm->mm_count);  in mmgrab()
51 	 * user-space, after storing to rq->curr.  in mmdrop()
53 	if (unlikely(atomic_dec_and_test(&mm->mm_count)))  in mmdrop()
76 	if (atomic_dec_and_test(&mm->mm_count))  in mmdrop_sched()
77 		call_rcu(&mm->delayed_drop, __mmdrop_delayed);  in mmdrop_sched()
115  * mmget() - Pin the address space associated with a &struct mm_struct.
127  * See also <Documentation/mm/active_mm.rst> for an in-depth explanation
132 	atomic_inc(&mm->mm_users);  in mmget()
137 	return atomic_inc_not_zero(&mm->mm_users);  in mmget_not_zero()
140 /* mmput gets rid of the mappings and all user-space */
207 	 * need RCU to access ->real_parent if CLONE_VM was used along with  in in_vfork()
210 	 * We check real_parent->mm == tsk->mm because CLONE_VFORK does not  in in_vfork()
214 	 * ->real_parent is not necessarily the task doing vfork(), so in  in in_vfork()
217 	 * And in this case we can't trust the real_parent->mm == tsk->mm  in in_vfork()
219 	 * another oom-unkillable task does this it should blame itself.  in in_vfork()
222 	ret = tsk->vfork_done &&  in in_vfork()
223 			rcu_dereference(tsk->real_parent)->mm == tsk->mm;  in in_vfork()
230  * Applies per-task gfp context to the given allocation flags.
237 	unsigned int pflags = READ_ONCE(current->flags);  in current_gfp_context()
267 /* Any memory-allocation retry loop should use
271  * and a central place to fine tune the waiting as the MM
294  * might_alloc - Mark possible allocation sites
310  * memalloc_noio_save - Marks implicit GFP_NOIO allocation scope.
322 	unsigned int flags = current->flags & PF_MEMALLOC_NOIO;  in memalloc_noio_save()
323 	current->flags |= PF_MEMALLOC_NOIO;  in memalloc_noio_save()
328  * memalloc_noio_restore - Ends the implicit GFP_NOIO scope.
337 	current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;  in memalloc_noio_restore()
341  * memalloc_nofs_save - Marks implicit GFP_NOFS allocation scope.
353 	unsigned int flags = current->flags & PF_MEMALLOC_NOFS;  in memalloc_nofs_save()
354 	current->flags |= PF_MEMALLOC_NOFS;  in memalloc_nofs_save()
359  * memalloc_nofs_restore - Ends the implicit GFP_NOFS scope.
368 	current->flags = (current->flags & ~PF_MEMALLOC_NOFS) | flags;  in memalloc_nofs_restore()
373 	unsigned int flags = current->flags & PF_MEMALLOC;  in memalloc_noreclaim_save()
374 	current->flags |= PF_MEMALLOC;  in memalloc_noreclaim_save()
380 	current->flags = (current->flags & ~PF_MEMALLOC) | flags;  in memalloc_noreclaim_restore()
385 	unsigned int flags = current->flags & PF_MEMALLOC_PIN;  in memalloc_pin_save()
387 	current->flags |= PF_MEMALLOC_PIN;  in memalloc_pin_save()
393 	current->flags = (current->flags & ~PF_MEMALLOC_PIN) | flags;  in memalloc_pin_restore()
399  * set_active_memcg - Starts the remote memcg charging scope.
422 		old = current->active_memcg;  in set_active_memcg()
423 		current->active_memcg = memcg;  in set_active_memcg()
459 	if (current->mm != mm)  in membarrier_mm_sync_core_before_usermode()
461 	if (likely(!(atomic_read(&mm->membarrier_state) &  in membarrier_mm_sync_core_before_usermode()