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
214  *	All references to the virtual page size outside this
279  *	For debugging, this should be a strange value
341  *	shared with this module, so that page allocation
455 	 * no point in this for a uni-processor system
693 	 *	wired, they nonetheless can't be moved. At this moment,
727 	 *	If this is the first call to pmap_steal_memory,
744 	 *	Allocate virtual memory for this request.
936          * in vm_page_create(). [Q: is this really what we want?]
949  *		vm_page_create turns this memory into available pages.
1023 	 * so this check isn't safe to make
1056 		 *	Record the object/offset pair in this page
1155 	 * so this check isn't safe to make
1168 	 *	Record the object/offset pair in this page
1216 		 * offset for this object... remove it from
1239 	vm_page_t	this;
1255 	 * so this check isn't safe to make
1269 		if ((this = bucket->pages) == mem) {
1276 			for (prev = &this->next;
1277 			     (this = *prev) != mem;
1278 			     prev = &this->next)
1280 			*prev = this->next;
1412 	 * Search the hash table for this object/offset pair
1419 	 * new pages can be inserted into this object... this in turn
1422 	 * at outside the scope of the hash bucket lock... this is a
1438 		 * so this check isn't safe to make
1488 	 * sets "encrypted_ok" in this case.
1537 	 * we're leaving this turned off for now... currently pages
1542 	 * Since we may change the way this works in the future (to toughen it up),
1543 	 * I'm leaving this as a reminder of where these bits could get cleared
1548 	 * clear at this point... we are especially dependent on
1550 	 * once this page goes back into use
1665 		 * and then call this routine. This routine finds the pages
1668 		 * of fictitious pages required in this manner is 2. 5 is
1711  * this is an interface to support bring-up of drivers
1718  * this interface exists to support hardware controllers
1790  *	this must be done while pre-emption is disabled... if
1886 			 * in this state since a non-privileged
1963 		 * satisfy this request
1975 	 *	We do this if the free count is less than the low
2036 		 * this exists to support hardware controllers
2075 		 *	while the page goes unused.  To forestall this,
2116 	 *	We can't use vm_page_free_reserved to make this
2163  *	with this VM object/offset pair.
2507 				 * after this, so let's wake them all up at
2527  *	Mark this page as wired down by yet
2607 		 * data is actually valid at this point.
2620  *      Mark this page as consumed by the vm/ipc/xmm subsystems.
2646  *	Release one wiring of this page, potentially
2701  *	to this page.  [Used by the physical mapping system.]
2736 	if (m->gobbled) {		/* can this happen? */
2745 	 * if this page is currently on the pageout queue, we can't do the
2811 	 * if this page is currently on the pageout queue, we can't do the
2863 	 * if this page is currently on the pageout queue, we can't do the
2930 	 * if this page is currently on the pageout queue, we can't do the
3059 	 * if this page is currently on the pageout queue, we can't do the
3146  * the nolocks == TRUE case is to allow this function to be run on
3249 	 * so this check isn't safe to make
3294 	 * so this check isn't safe to make
3320 	 * so this check isn't safe to make
3355 	 * so this check isn't safe to make
3364 	 * The source page should not be encrypted at this point.
3628  *	ordered, ascending list... this is currently true of all our implementations
3638  *	meets this criterea and is physically contiguous to the previous page in the 'run'
3640  *	and start to develop a new run... if at this point we've already considered
3648  *	must be removed from the object they are tabled on... this requires taking the
3649  * 	object lock... we do this as a 'try' to prevent deadlocks... if the 'try' fails
3787 			 * locks we hold at this point...
3829 				 * we have to give up this run
3832 				 * move the contents of this page
3846 				 * if we let this run continue
3849 				 * this run, but we can at least re-consider this
3861 				 * we went to retry in this case, we'd
3864 				 * we also want to take this path if we've already
3933 		 * free pages in this run and return them to the free list
3960 				 * Clear the "free" bit so that this page
3982 		 * we can drop the free queue lock at this point since
4075 					 * for this purpose it looks like it
4084 					 * this page was used...
4104 					 * for this purpose it looks like it
4131 			 * page in this run that was
4134 			 * and 1 more to bump back over this page
4305 	 * if this object contains the majority of the pages resident
4348 			 * Add this page to our list of reclaimed pages,
4365 				 * if we didn't hold the object lock and did this,
4375 					 * this page has been touched since it got cleaned; let's activate it
4615 			 * page queues lock, we can only 'try' for this one.
4733 		 * means this page can't be on the pageout queue so it's
4976             *	Somebody is playing with this page.