2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
129 lines
5.1 KiB
C
129 lines
5.1 KiB
C
/* $NetBSD: dirhash.h,v 1.6 2008/06/04 11:33:19 ad Exp $ */
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/*
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* Copyright (c) 2001 Ian Dowse. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD: src/sys/ufs/ufs/dirhash.h,v 1.2.2.2 2004/12/08 11:54:13 dwmalone Exp $
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*/
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#ifndef _UFS_UFS_DIRHASH_H_
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#define _UFS_UFS_DIRHASH_H_
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/*
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* For fast operations on large directories, we maintain a hash
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* that maps the file name to the offset of the directory entry within
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* the directory file.
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*
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* The hashing uses a dumb spillover to the next free slot on
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* collisions, so we must keep the utilisation low to avoid
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* long linear searches. Deleted entries that are not the last
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* in a chain must be marked DIRHASH_DEL.
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*
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* We also maintain information about free space in each block
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* to speed up creations.
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*/
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#define DIRHASH_EMPTY (-1) /* entry unused */
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#define DIRHASH_DEL (-2) /* deleted entry; may be part of chain */
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#define DIRALIGN 4
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#define DH_NFSTATS (DIRECTSIZ(FFS_MAXNAMLEN + 1) / DIRALIGN)
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/* max DIRALIGN words in a directory entry */
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/*
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* Dirhash uses a score mechanism to achieve a hybrid between a
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* least-recently-used and a least-often-used algorithm for entry
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* recycling. The score is incremented when a directory is used, and
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* decremented when the directory is a candidate for recycling. When
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* the score reaches zero, the hash is recycled. Hashes are linked
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* together on a TAILQ list, and hashes with higher scores filter
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* towards the tail (most recently used) end of the list.
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*
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* New hash entries are given an inital score of DH_SCOREINIT and are
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* placed at the most-recently-used end of the list. This helps a lot
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* in the worst-case case scenario where every directory access is
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* to a directory that is not hashed (i.e. the working set of hash
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* candidates is much larger than the configured memry limit). In this
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* case it limits the number of hash builds to 1/DH_SCOREINIT of the
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* number of accesses.
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*/
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#define DH_SCOREINIT 8 /* initial dh_score when dirhash built */
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#define DH_SCOREMAX 64 /* max dh_score value */
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/*
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* The main hash table has 2 levels. It is an array of pointers to
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* blocks of DH_NBLKOFF offsets.
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*/
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#define DH_BLKOFFSHIFT 8
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#define DH_NBLKOFF (1 << DH_BLKOFFSHIFT)
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#define DH_BLKOFFMASK (DH_NBLKOFF - 1)
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#define DH_ENTRY(dh, slot) \
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((dh)->dh_hash[(slot) >> DH_BLKOFFSHIFT][(slot) & DH_BLKOFFMASK])
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struct dirhash {
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kmutex_t dh_lock; /* protects all fields except dh_list */
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doff_t **dh_hash; /* the hash array (2-level) */
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size_t dh_hashsz;
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int dh_narrays; /* number of entries in dh_hash */
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int dh_hlen; /* total slots in the 2-level hash array */
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int dh_hused; /* entries in use */
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u_int8_t *dh_blkfree; /* free DIRALIGN words in each dir block */
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size_t dh_blkfreesz;
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int dh_nblk; /* size of dh_blkfree array */
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int dh_dirblks; /* number of DIRBLKSIZ blocks in dir */
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int dh_firstfree[DH_NFSTATS + 1]; /* first blk with N words free */
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int dh_seqopt; /* sequential access optimisation enabled */
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doff_t dh_seqoff; /* sequential access optimisation offset */
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int dh_score; /* access count for this dirhash */
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int dh_onlist; /* true if on the ufsdirhash_list chain */
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/* Protected by ufsdirhash_lock. */
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TAILQ_ENTRY(dirhash) dh_list; /* chain of all dirhashes */
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};
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/*
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* Dirhash functions.
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*/
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int ufsdirhash_build(struct inode *);
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doff_t ufsdirhash_findfree(struct inode *, int, int *);
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doff_t ufsdirhash_enduseful(struct inode *);
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int ufsdirhash_lookup(struct inode *, const char *, int, doff_t *,
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struct buf **, doff_t *);
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void ufsdirhash_newblk(struct inode *, doff_t);
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void ufsdirhash_add(struct inode *, struct direct *, doff_t);
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void ufsdirhash_remove(struct inode *, struct direct *, doff_t);
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void ufsdirhash_move(struct inode *, struct direct *, doff_t, doff_t);
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void ufsdirhash_dirtrunc(struct inode *, doff_t);
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void ufsdirhash_free(struct inode *);
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void ufsdirhash_checkblock(struct inode *, char *, doff_t);
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void ufsdirhash_init(void);
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void ufsdirhash_done(void);
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#endif /* !_UFS_UFS_DIRHASH_H_ */
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