osfmk/default_pager/dp_backing_store.c

107  * 0 means no shift to pages, so == 1 page/cluster. 1 would mean
108  * 2 pages/cluster, 2 means 4 pages/cluster, and so on.
524 	 * Only allow setting of cluster size once. If called
525 	 * with no cluster size (default), we use the compiled-in default
526 	 * for the duration. The same cluster size is used for all
531 		 * Keep cluster size in bit shift because it's quicker
543 		 * Let the user know the new (and definitive) cluster size.
1520 				 * Force the ps cluster size to be
1595 	dp_offset_t		cluster;
1600 	 * ps_select_segment will decrement cluster count on ps.
1601 	 * Must pass cluster shift to find the most appropriate segment.
1749 	 * Look for an available cluster.  At the end of the loop,
1766 	cluster = (byte_num*NBBY) + bit_num;
1769 	ASSERT(cluster < ps->ps_ncls);
1771 	setbit(ps->ps_bmap, cluster);
1774 	return cluster;
1782 	dp_offset_t		cluster)
1785 	if (cluster >= ps->ps_ncls)
1786 		panic("ps_deallocate_cluster: Invalid cluster number");
1789 	 * Lock the paging segment, clear the cluster's bitmap and increment the
1790 	 * number of free cluster.
1794 	clrbit(ps->ps_bmap, cluster);
1804 	 * Move the hint down to the freed cluster if it is
1807 	if ((cluster/NBBY) < ps->ps_hint) {
1808 		ps->ps_hint = (cluster/NBBY);
1951 						(dp_size_t) -1, /* read whole cluster */
1991 					(dp_size_t) -1, /* read whole cluster */
2130 	dp_offset_t	cluster;	/* The cluster of offset.	*/
2131 	dp_offset_t	newcl;		/* The new cluster allocated.	*/
2139 	cluster = atop_32(offset) >> vs->vs_clshift;
2142 	 * Initialize cluster error value
2149 	if (cluster >= vs->vs_size) {
2155 		if (ps_map_extend(vs, cluster + 1)) {
2162 	 * Look for the desired cluster.  If the map is indirect, then we
2164 	 * find the actual cluster.  If the indirect block has not yet
2165 	 * been allocated, then do so.  If the cluster has not yet been
2172 		long	ind_block = cluster/CLMAP_ENTRIES;
2188 			/* Initialize the cluster offsets */
2197 	vsmap += cluster%CLMAP_ENTRIES;
2202 	 * Look in the map for the cluster, if there was an error on a
2205 	 * doing a lookup and the cluster's not allocated, return error.
2227 			 * Attempt to allocate a cluster from the paging segment
2250 	 * Byte offset in paging segment is byte offset to cluster plus
2251 	 * byte offset within cluster.  It looks ugly, but should be
2272 		 * Offset is not cluster aligned, so number of pages
2288 	 * then the error number is recorded in the cluster and the
2289 	 * entire cluster is in error.
2309 		 * Deallocate cluster if error, and no valid pages
2338 	dp_offset_t		cluster; /* The cluster number of offset */
2354 		cluster = atop_32(offset) >> vs->vs_clshift;
2356 			vsmap = vs->vs_imap[cluster/CLMAP_ENTRIES];
2364 		vsmap += cluster%CLMAP_ENTRIES;
2373 		 * paging segment cluster pages.
2374 		 * Optimize for entire cluster cleraing.
2378 			 * Not cluster aligned.
2393 		 * If map entry is empty, clear and deallocate cluster.
2424 	 * Get the struct vsmap for this cluster.
2426 	 * cluster MUST be present, unless there was an error
2453 		 * per-cluster basis by ps_clmap() which is called
2889  * store all existing pages in the cluster containing "vs_offset".
2942 		 * if the I/O cluster size == PAGE_SIZE, we don't want to set
2975 				/* no more pages in this cluster */
2978 			/* try the next page in this cluster */
3067 	 * range has been looked at or we issue an I/O... if the request spans cluster
3131 					 * if we're at the end of this physical cluster
3217 				 * we've hit a hole in our speculative cluster
3315 			 * we ran into a 'hole' (i.e. page not present in the cluster, cluster
3704 				/* loop on pages in this cluster */
3720 			/* loop on pages in this cluster */
3760 				/* loop on pages in this cluster */
3783 			/* loop on pages in this cluster */
3943 	dp_offset_t	cluster;
3945 	cluster = atop_32(offset) >> vs->vs_clshift;
3947 		long	ind_block = cluster/CLMAP_ENTRIES;
3955 	vsmap += cluster%CLMAP_ENTRIES;
3983 	/* vs_cluster_transfer reads in the pages of a cluster and
3991 	 * This loop will be executed once per cluster referenced.
3993 	 * VM system will ask for anything spanning cluster boundaries.
3995 	 * If there are holes in a cluster (in a paging segment), we stop
3997 	 * find valid pages later in the cluster.  This continues until
4015 			 * Nothing left to write in this cluster at least
4016 			 * set write cluster information for any previous
4017 			 * write, clear for next cluster, if there is one
4027 			/* This cluster has no data in it beyond what may */
4071 				   cluster
4140 					   cluster
4180 					 * for the purposes of cluster transfer
4369 	/* level.  It is up to the bit map code and cluster read code to     */