osfmk/vm/vm_resident.c

8  * Version 2.0 (the 'License'). You may not use this file except in
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
36  * Permission to use, copy, modify and distribute this software and its
38  * notice and this permission notice appear in all copies of the
46  * Carnegie Mellon requests users of this software to return to
218  *	All references to the virtual page size outside this
283  *	For debugging, this should be a strange value
350  *	shared with this module, so that page allocation
466 	 * no point in this for a uni-processor system
736 	 *	wired, they nonetheless can't be moved. At this moment,
770 	 *	If this is the first call to pmap_steal_memory,
787 	 *	Allocate virtual memory for this request.
978          * in vm_page_create(). [Q: is this really what we want?]
991  *		vm_page_create turns this memory into available pages.
1065 	 * so this check isn't safe to make
1100 		 *	Record the object/offset pair in this page
1219 	 * so this check isn't safe to make
1232 	 *	Record the object/offset pair in this page
1282 		 * offset for this object... remove it from
1305 	vm_page_t	this;
1321 	 * so this check isn't safe to make
1335 		if ((this = bucket->pages) == mem) {
1342 			for (prev = &this->next;
1343 			     (this = *prev) != mem;
1344 			     prev = &this->next)
1346 			*prev = this->next;
1485 	 * Search the hash table for this object/offset pair
1492 	 * new pages can be inserted into this object... this in turn
1495 	 * at outside the scope of the hash bucket lock... this is a
1511 		 * so this check isn't safe to make
1563 	 * sets "encrypted_ok" in this case.
1588 		 * for this to matter.
1642 	 * we're leaving this turned off for now... currently pages
1647 	 * Since we may change the way this works in the future (to toughen it up),
1648 	 * I'm leaving this as a reminder of where these bits could get cleared
1653 	 * clear at this point... we are especially dependent on
1655 	 * once this page goes back into use
1770 		 * and then call this routine. This routine finds the pages
1773 		 * of fictitious pages required in this manner is 2. 5 is
1820  * this is an interface to support bring-up of drivers
1827  * this interface exists to support hardware controllers
1899  *	this must be done while pre-emption is disabled... if
1995 			 * in this state since a non-privileged
2072 		 * satisfy this request
2084 	 *	We do this if the free count is less than the low
2145 		 * this exists to support hardware controllers
2184 		 *	while the page goes unused.  To forestall this,
2225 	 *	We can't use vm_page_free_reserved to make this
2276  *	with this VM object/offset pair.
2620 				 * after this, so let's wake them all up at
2640  *	Mark this page as wired down by yet
2720 		 * data is actually valid at this point.
2733  *      Mark this page as consumed by the vm/ipc/xmm subsystems.
2759  *	Release one wiring of this page, potentially
2814  *	to this page.  [Used by the physical mapping system.]
2849 	if (m->gobbled) {		/* can this happen? */
2858 	 * if this page is currently on the pageout queue, we can't do the
2924 	 * if this page is currently on the pageout queue, we can't do the
2987 	 * if this page is currently on the pageout queue, we can't do the
3090 	 * if this page is currently on the pageout queue, we can't do the
3224 	 * if this page is currently on the pageout queue, we can't do the
3321  * the nolocks == TRUE case is to allow this function to be run on
3428 	 * so this check isn't safe to make
3474 	 * so this check isn't safe to make
3500 	 * so this check isn't safe to make
3535 	 * so this check isn't safe to make
3544 	 * The source page should not be encrypted at this point.
3808  *	ordered, ascending list... this is currently true of all our implementations
3818  *	meets this criterea and is physically contiguous to the previous page in the 'run'
3820  *	and start to develop a new run... if at this point we've already considered
3828  *	must be removed from the object they are tabled on... this requires taking the
3829  * 	object lock... we do this as a 'try' to prevent deadlocks... if the 'try' fails
3971 			 * locks we hold at this point...
4013 				 * we have to give up this run
4016 				 * move the contents of this page
4030 				 * if we let this run continue
4033 				 * this run, but we can at least re-consider this
4045 				 * we went to retry in this case, we'd
4048 				 * we also want to take this path if we've already
4121 		 * free pages in this run and return them to the free list
4148 				 * Clear the "free" bit so that this page
4170 		 * we can drop the free queue lock at this point since
4335 					 * this page was used...
4350 					 * for this purpose it looks like it
4385 					 * for this purpose it looks like it
4412 			 * page in this run that was
4415 			 * and 1 more to bump back over this page
4588 	 * if this object contains the majority of the pages resident
4631 			 * Add this page to our list of reclaimed pages,
4648 				 * if we didn't hold the object lock and did this,
4658 					 * this page has been touched since it got cleaned; let's activate it
4920 			 * page queues lock, we can only 'try' for this one.
5050 		 * means this page can't be on the pageout queue so it's
5329             *	Somebody is playing with this page.
6142 		 * this vm_page_t must be located in "next".
6151 			 * this vm_page_t was moved by hibernate_teardown_vm_structs,
6160 		 * the 'hole' between this vm_page_t and the previous
6271 			 * record this vm_page_t's original location
6272 			 * we need this even if it doesn't get moved
6281 				 * move this vm_page_t to it's new home