osfmk/kern/zalloc.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
107  * "zp-factor=N" as a boot-arg. To turn this feature off, set "zp-factor=0" or "-no-zp".
116  * As a result, each element (that is large enough to hold this data inside) must be marked
130  * "zlog=<zone name to log> -zc". Search for "Zone corruption logging" later in this
153  * Frees the specified element, which is within the specified zone. If this
164 	/* should we run checks on this piece of memory? */
284  * physical page is returned to the VM system. During this process, the
420  * When enabled, this code keeps a log to track allocations to a particular zone that have not
421  * yet been freed.  Examining this log will reveal the source of a zone leak.  The log is allocated
432  * is most likely the problem zone, so set zlog in boot-args to this zone name, reboot and re-run the test.  The
433  * next time it panics with this message, examine the log using the kgmacros zstack, findoldest and countpcs.
454  * The number of records in the log is configurable via the zrecs parameter in boot-args.  Set this to
458  * records since going much larger than this tends to make the system unresponsive and unbootable on small
502  * Decide if we want to log this zone by doing a string compare between a zone name and the name
543  * Test if we want to log this zalloc/zfree event.  We log if this is the zone we're interested in and
607 	vm_size_t		za_size;			/* how much memory did this allocation take up? */
609 	/* TODO: #if this out */
623 /* not static so that panic can see this, see kern/debug.c */
865 		if (trace->zt_depth != 0) /* if this slot was previously used but not currently in use */
964  * If this function is inlined, it doesn't record the frame of the function it's inside.
1058  *  TODO: Determine how well distributed this is
1211 	 * Check if we should be logging this zone.  If so, remember the zone pointer.
1229 			 * We got the memory for the log.  Zero it out since the code needs this to identify unused records.
1230 			 * At this point, everything is set up and we're ready to start logging this zone.
1674 	uint32_t	zleak_tracedepth = 0;  /* log this allocation if nonzero */
1687 	 * If zone logging is turned on and this is the zone we're tracking, grab a backtrace.
1696 	 * allocations in this zone.
1725 			 *	Someone is allocating memory for this zone.
1830 						/* TODO: Change this to something more descriptive, perhaps
1860 	 * If we're sampling this allocation, add it to the zleaks hash table.
1873 	 * See if we should be logging allocations in this zone.  Logging is rarely done except when a leak is
1874 	 * suspected, so this code rarely executes.  We need to do this code while still holding the zone lock
1881 		 * Look for a place to record this new allocation.  We implement two different logging strategies
1887 		 * element can be inspected.  So in this case, we treat the log as a circular buffer and overwrite the
1919 		 * Save a record of this allocation
2023  *	XXX: It seems like only vm_page_grab_fictitious_common uses this, and its
2025  *  this is used for interrupts any more....
2035 	uint32_t	zleak_tracedepth = 0;  /* log this allocation if nonzero */
2083 /* Keep this FALSE by default.  Large memory machine run orders of magnitude
2103 	 * If zone logging is turned on and this is the zone we're tracking, grab a backtrace.
2137 	 * See if we're doing logging on this zone.  There are two styles of logging used depending on
2147 			 * We're logging to catch a corruption.  Add a record of this zfree operation
2172 			 * We're logging to catch a leak. Remove any record we might have for this
2210 		vm_offset_t this;
2214 		for (this = zone->free_elements;
2215 		     this != 0;
2216 		     this = * (vm_offset_t *) this)
2217 			if (!pmap_kernel_va(this) || this == elem)
2526 			 * This element was the last one on this page, re-use the page's
2781 				 * If this is the last allocation on the page(s),