0d94caffca
much higher filesystem I/O performance, and much better paging performance. It represents the culmination of over 6 months of R&D. The majority of the merged VM/cache work is by John Dyson. The following highlights the most significant changes. Additionally, there are (mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to support the new VM/buffer scheme. vfs_bio.c: Significant rewrite of most of vfs_bio to support the merged VM buffer cache scheme. The scheme is almost fully compatible with the old filesystem interface. Significant improvement in the number of opportunities for write clustering. vfs_cluster.c, vfs_subr.c Upgrade and performance enhancements in vfs layer code to support merged VM/buffer cache. Fixup of vfs_cluster to eliminate the bogus pagemove stuff. vm_object.c: Yet more improvements in the collapse code. Elimination of some windows that can cause list corruption. vm_pageout.c: Fixed it, it really works better now. Somehow in 2.0, some "enhancements" broke the code. This code has been reworked from the ground-up. vm_fault.c, vm_page.c, pmap.c, vm_object.c Support for small-block filesystems with merged VM/buffer cache scheme. pmap.c vm_map.c Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of kernel PTs. vm_glue.c Much simpler and more effective swapping code. No more gratuitous swapping. proc.h Fixed the problem that the p_lock flag was not being cleared on a fork. swap_pager.c, vnode_pager.c Removal of old vfs_bio cruft to support the past pseudo-coherency. Now the code doesn't need it anymore. machdep.c Changes to better support the parameter values for the merged VM/buffer cache scheme. machdep.c, kern_exec.c, vm_glue.c Implemented a seperate submap for temporary exec string space and another one to contain process upages. This eliminates all map fragmentation problems that previously existed. ffs_inode.c, ufs_inode.c, ufs_readwrite.c Changes for merged VM/buffer cache. Add "bypass" support for sneaking in on busy buffers. Submitted by: John Dyson and David Greenman
230 lines
9.5 KiB
C
230 lines
9.5 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* @(#)buf.h 8.7 (Berkeley) 1/21/94
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* $Id: buf.h,v 1.10 1994/10/18 06:55:57 davidg Exp $
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*/
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#ifndef _SYS_BUF_H_
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#define _SYS_BUF_H_
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#include <sys/queue.h>
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#define NOLIST ((struct buf *)0x87654321)
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/*
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* The buffer header describes an I/O operation in the kernel.
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*/
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struct buf {
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LIST_ENTRY(buf) b_hash; /* Hash chain. */
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LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
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TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
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struct buf *b_actf, **b_actb; /* Device driver queue when active. */
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struct proc *b_proc; /* Associated proc; NULL if kernel. */
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volatile long b_flags; /* B_* flags. */
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int b_qindex; /* buffer queue index */
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int b_error; /* Errno value. */
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long b_bufsize; /* Allocated buffer size. */
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long b_bcount; /* Valid bytes in buffer. */
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long b_resid; /* Remaining I/O. */
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dev_t b_dev; /* Device associated with buffer. */
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struct {
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caddr_t b_addr; /* Memory, superblocks, indirect etc. */
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} b_un;
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void *b_saveaddr; /* Original b_addr for physio. */
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daddr_t b_lblkno; /* Logical block number. */
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daddr_t b_blkno; /* Underlying physical block number. */
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/* Function to call upon completion. */
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void (*b_iodone) __P((struct buf *));
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struct vnode *b_vp; /* Device vnode. */
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int b_pfcent; /* Center page when swapping cluster. */
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int b_dirtyoff; /* Offset in buffer of dirty region. */
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int b_dirtyend; /* Offset of end of dirty region. */
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struct ucred *b_rcred; /* Read credentials reference. */
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struct ucred *b_wcred; /* Write credentials reference. */
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int b_validoff; /* Offset in buffer of valid region. */
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int b_validend; /* Offset of end of valid region. */
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daddr_t b_pblkno; /* physical block number */
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caddr_t b_savekva; /* saved kva for transfer while bouncing */
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void *b_driver1; /* for private use by the driver */
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void *b_driver2; /* for private use by the driver */
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void *b_spc;
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#ifndef VMIO
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void *b_pages[(MAXPHYS + PAGE_SIZE - 1)/PAGE_SIZE];
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#else
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struct vm_page *b_pages[(MAXPHYS + PAGE_SIZE - 1)/PAGE_SIZE];
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#endif
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int b_npages;
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};
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/* Device driver compatibility definitions. */
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#define b_active b_bcount /* Driver queue head: drive active. */
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#define b_data b_un.b_addr /* b_un.b_addr is not changeable. */
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#define b_errcnt b_resid /* Retry count while I/O in progress. */
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#define iodone biodone /* Old name for biodone. */
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#define iowait biowait /* Old name for biowait. */
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/*
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* These flags are kept in b_flags.
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*/
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#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
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#define B_APPENDWRITE 0x00000002 /* Append-write in progress. */
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#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
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#define B_BAD 0x00000008 /* Bad block revectoring in progress. */
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#define B_BUSY 0x00000010 /* I/O in progress. */
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#define B_CACHE 0x00000020 /* Bread found us in the cache. */
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#define B_CALL 0x00000040 /* Call b_iodone from biodone. */
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#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
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#define B_DIRTY 0x00000100 /* Dirty page to be pushed out async. */
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#define B_DONE 0x00000200 /* I/O completed. */
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#define B_EINTR 0x00000400 /* I/O was interrupted */
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#define B_ERROR 0x00000800 /* I/O error occurred. */
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#define B_GATHERED 0x00001000 /* LFS: already in a segment. */
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#define B_INVAL 0x00002000 /* Does not contain valid info. */
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#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
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#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
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#define B_MALLOC 0x00010000 /* malloced b_data */
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#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
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#define B_PHYS 0x00040000 /* I/O to user memory. */
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#define B_RAW 0x00080000 /* Set by physio for raw transfers. */
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#define B_READ 0x00100000 /* Read buffer. */
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#define B_TAPE 0x00200000 /* Magnetic tape I/O. */
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#define B_PDWANTED 0x00400000 /* Pageout daemon wants this buffer. */
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#define B_WANTED 0x00800000 /* Process wants this buffer. */
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#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
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#define B_WRITEINPROG 0x01000000 /* Write in progress. */
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#define B_XXX 0x02000000 /* Debugging flag. */
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#define B_VMIO 0x20000000 /* VMIO flag */
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#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
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#define B_BOUNCE 0x80000000 /* bounce buffer flag */
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/*
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* This structure describes a clustered I/O. It is stored in the b_saveaddr
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* field of the buffer on which I/O is done. At I/O completion, cluster
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* callback uses the structure to parcel I/O's to individual buffers, and
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* then free's this structure.
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*/
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struct cluster_save {
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long bs_bcount; /* Saved b_bcount. */
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long bs_bufsize; /* Saved b_bufsize. */
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void *bs_saveaddr; /* Saved b_addr. */
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int bs_nchildren; /* Number of associated buffers. */
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struct buf **bs_children; /* List of associated buffers. */
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};
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/*
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* number of buffer hash entries
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*/
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#define BUFHSZ 512
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/*
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* buffer hash table calculation, originally by David Greenman
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*/
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#define BUFHASH(vnp, bn) \
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(&bufhashtbl[(((int)(vnp) / sizeof(struct vnode))+(int)(bn)) % BUFHSZ])
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/*
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* Definitions for the buffer free lists.
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*/
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#define BUFFER_QUEUES 6 /* number of free buffer queues */
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LIST_HEAD(bufhashhdr, buf) bufhashtbl[BUFHSZ], invalhash;
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TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES];
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#define QUEUE_NONE 0 /* on no queue */
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#define QUEUE_LOCKED 1 /* locked buffers */
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#define QUEUE_LRU 2 /* useful buffers */
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#define QUEUE_VMIO 3 /* VMIO buffers */
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#define QUEUE_AGE 4 /* not-useful buffers */
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#define QUEUE_EMPTY 5 /* empty buffer headers*/
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/*
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* Zero out the buffer's data area.
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*/
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#define clrbuf(bp) { \
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blkclr((bp)->b_data, (u_int)(bp)->b_bcount); \
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(bp)->b_resid = 0; \
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}
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/* Flags to low-level allocation routines. */
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#define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */
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#define B_SYNC 0x02 /* Do all allocations synchronously. */
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#ifdef KERNEL
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extern int nbuf; /* The number of buffer headers */
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extern struct buf *buf; /* The buffer headers. */
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extern char *buffers; /* The buffer contents. */
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extern int bufpages; /* Number of memory pages in the buffer pool. */
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extern struct buf *swbuf; /* Swap I/O buffer headers. */
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extern int nswbuf; /* Number of swap I/O buffer headers. */
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extern TAILQ_HEAD(swqueue, buf) bswlist;
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__BEGIN_DECLS
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void bufinit __P((void));
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void bremfree __P((struct buf *));
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int bread __P((struct vnode *, daddr_t, int,
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struct ucred *, struct buf **));
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int breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
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struct ucred *, struct buf **));
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int bwrite __P((struct buf *));
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void bdwrite __P((struct buf *));
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void bawrite __P((struct buf *));
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void brelse __P((struct buf *));
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struct buf *getnewbuf __P((int slpflag, int slptimeo, int));
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struct buf * getpbuf __P((void));
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struct buf *incore __P((struct vnode *, daddr_t));
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struct buf *getblk __P((struct vnode *, daddr_t, int, int, int));
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struct buf *geteblk __P((int));
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int allocbuf __P((struct buf *, int, int));
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int biowait __P((struct buf *));
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void biodone __P((struct buf *));
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void cluster_callback __P((struct buf *));
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int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
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struct ucred *, struct buf **));
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void cluster_write __P((struct buf *, u_quad_t));
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u_int minphys __P((struct buf *));
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void vwakeup __P((struct buf *));
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void vmapbuf __P((struct buf *));
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void vunmapbuf __P((struct buf *));
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void relpbuf __P((struct buf *));
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void brelvp __P((struct buf *));
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void bgetvp __P((struct vnode *, struct buf *));
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void reassignbuf __P((struct buf *, struct vnode *));
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__END_DECLS
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#endif
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#endif /* !_SYS_BUF_H_ */
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