[unix-history] / usr / src / sbin / newlfs / config.h

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)config.h	5.3 (Berkeley) %G%
 */

/*
 * The following two constants set the default block and fragment sizes.
 * Both constants must be a power of 2 and meet the following constraints:
 *	MINBSIZE <= DESBLKSIZE <= MAXBSIZE
 *	sectorsize <= DESFRAGSIZE <= DESBLKSIZE
 *	DESBLKSIZE / DESFRAGSIZE <= 8
 */
#define	DFL_FRAGSIZE	1024
#define	DFL_BLKSIZE	8192

/*
 * Cylinder groups may have up to many cylinders. The actual
 * number used depends upon how much information can be stored
 * on a single cylinder. The default is to use 16 cylinders
 * per group.
 */
#define	DESCPG		16	/* desired fs_cpg */

/*
 * MINFREE gives the minimum acceptable percentage of file system
 * blocks which may be free. If the freelist drops below this level
 * only the superuser may continue to allocate blocks. This may
 * be set to 0 if no reserve of free blocks is deemed necessary,
 * however throughput drops by fifty percent if the file system
 * is run at between 90% and 100% full; thus the default value of
 * fs_minfree is 10%. With 10% free space, fragmentation is not a
 * problem, so we choose to optimize for time.
 */
#define MINFREE		10
#define DEFAULTOPT	FS_OPTTIME

/*
 * ROTDELAY gives the minimum number of milliseconds to initiate
 * another disk transfer on the same cylinder. It is used in
 * determining the rotationally optimal layout for disk blocks
 * within a file; the default of fs_rotdelay is 4ms.
 */
#define ROTDELAY	4

/*
 * MAXCONTIG sets the default for the maximum number of blocks
 * that may be allocated sequentially. Since UNIX drivers are
 * not capable of scheduling multi-block transfers, this defaults
 * to 1 (ie no contiguous blocks are allocated).
 */
#define MAXCONTIG	1

/*
 * MAXBLKPG determines the maximum number of data blocks which are
 * placed in a single cylinder group. The default is one indirect
 * block worth of data blocks.
 */
#define MAXBLKPG(bsize)	((bsize) / sizeof(daddr_t))

/*
 * Each file system has a number of inodes statically allocated.
 * We allocate one inode slot per NFPI fragments, expecting this
 * to be far more than we will ever need.
 */
#define	NFPI		4

/*
 * For each cylinder we keep track of the availability of blocks at different
 * rotational positions, so that we can lay out the data to be picked
 * up with minimum rotational latency.  NRPOS is the default number of
 * rotational positions that we distinguish.  With NRPOS of 8 the resolution
 * of our summary information is 2ms for a typical 3600 rpm drive.
 */
#define	NRPOS		8	/* number distinct rotational positions */

/*
 * The following constants set the default block and segment size for a log
 * structured file system.  Both must be powers of two and the segment size
 * must be a multiple of the block size.  We also set minimum block and segment
 * sizes.
 */
#define	LFS_MINSEGSIZE		(128*1024)
#define	DFL_LFSSEG		(1024 * 1024)
#define	DFL_LFSSEG_SHIFT	20
#define	DFL_LFSSEG_MASK		0xFFFFF

#define	LFS_MINBLOCKSIZE	1024
#define	DFL_LFSBLOCK		4096
#define	DFL_LFSBLOCK_SHIFT	12
#define	DFL_LFSBLOCK_MASK	0xFFF
Commit	Line	Data
e60bcb33 KB	1	/*-
	2	* Copyright (c) 1991 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* %sccs.include.redist.c%
	6	*
0f1b9d3c	7	* @(#)config.h 5.3 (Berkeley) %G%
e60bcb33 KB	8	*/
	9
	10	/*
	11	* The following two constants set the default block and fragment sizes.
	12	* Both constants must be a power of 2 and meet the following constraints:
	13	* MINBSIZE <= DESBLKSIZE <= MAXBSIZE
	14	* sectorsize <= DESFRAGSIZE <= DESBLKSIZE
	15	* DESBLKSIZE / DESFRAGSIZE <= 8
	16	*/
	17	#define DFL_FRAGSIZE 1024
	18	#define DFL_BLKSIZE 8192
	19
	20	/*
	21	* Cylinder groups may have up to many cylinders. The actual
	22	* number used depends upon how much information can be stored
	23	* on a single cylinder. The default is to use 16 cylinders
	24	* per group.
	25	*/
	26	#define DESCPG 16 /* desired fs_cpg */
	27
	28	/*
	29	* MINFREE gives the minimum acceptable percentage of file system
	30	* blocks which may be free. If the freelist drops below this level
	31	* only the superuser may continue to allocate blocks. This may
	32	* be set to 0 if no reserve of free blocks is deemed necessary,
	33	* however throughput drops by fifty percent if the file system
	34	* is run at between 90% and 100% full; thus the default value of
	35	* fs_minfree is 10%. With 10% free space, fragmentation is not a
	36	* problem, so we choose to optimize for time.
	37	*/
	38	#define MINFREE 10
	39	#define DEFAULTOPT FS_OPTTIME
	40
	41	/*
	42	* ROTDELAY gives the minimum number of milliseconds to initiate
	43	* another disk transfer on the same cylinder. It is used in
	44	* determining the rotationally optimal layout for disk blocks
	45	* within a file; the default of fs_rotdelay is 4ms.
	46	*/
	47	#define ROTDELAY 4
	48
	49	/*
	50	* MAXCONTIG sets the default for the maximum number of blocks
	51	* that may be allocated sequentially. Since UNIX drivers are
	52	* not capable of scheduling multi-block transfers, this defaults
	53	* to 1 (ie no contiguous blocks are allocated).
	54	*/
	55	#define MAXCONTIG 1
	56
	57	/*
	58	* MAXBLKPG determines the maximum number of data blocks which are
	59	* placed in a single cylinder group. The default is one indirect
	60	* block worth of data blocks.
	61	*/
	62	#define MAXBLKPG(bsize) ((bsize) / sizeof(daddr_t))
	63
	64	/*
	65	* Each file system has a number of inodes statically allocated.
	66	* We allocate one inode slot per NFPI fragments, expecting this
	67	* to be far more than we will ever need.
	68	*/
	69	#define NFPI 4
	70
	71	/*
72	* For each cylinder we keep track of the availability of blocks at different
73	* rotational positions, so that we can lay out the data to be picked
74	* up with minimum rotational latency. NRPOS is the default number of
75	* rotational positions that we distinguish. With NRPOS of 8 the resolution
76	* of our summary information is 2ms for a typical 3600 rpm drive.
77	*/
78	#define NRPOS 8 /* number distinct rotational positions */
79
80	/*
81	* The following constants set the default block and segment size for a log
82	* structured file system. Both must be powers of two and the segment size
83	* must be a multiple of the block size. We also set minimum block and segment
84	* sizes.
85	*/
86	#define LFS_MINSEGSIZE (128*1024)
87	#define DFL_LFSSEG (1024 * 1024)
88	#define DFL_LFSSEG_SHIFT 20
b621ba9d	89	#define DFL_LFSSEG_MASK 0xFFFFF
e60bcb33 KB	90
	91	#define LFS_MINBLOCKSIZE 1024
	92	#define DFL_LFSBLOCK 4096
	93	#define DFL_LFSBLOCK_SHIFT 12
0f1b9d3c	94	#define DFL_LFSBLOCK_MASK 0xFFF