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mirror of https://git.FreeBSD.org/src.git synced 2024-12-24 11:29:10 +00:00
freebsd/sys/kern/vfs_cluster.c
1995-12-07 12:48:31 +00:00

707 lines
18 KiB
C

/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
* Modifications/enhancements:
* Copyright (c) 1995 John S. Dyson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
* $Id: vfs_cluster.c,v 1.28 1995/11/20 04:53:45 dyson Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/resourcevar.h>
#include <sys/vmmeter.h>
#include <miscfs/specfs/specdev.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#ifdef DEBUG
#include <vm/vm.h>
#include <sys/sysctl.h>
int doreallocblks = 0;
SYSCTL_INT(_debug, 13, doreallocblks, CTLFLAG_RW, &doreallocblks, 0, "");
#else
/* XXX for cluster_write */
#define doreallocblks 0
#endif
/*
* Local declarations
*/
static struct buf *cluster_rbuild __P((struct vnode *, u_quad_t,
daddr_t, daddr_t, long, int));
struct cluster_save *cluster_collectbufs __P((struct vnode *, struct buf *));
int totreads;
int totreadblocks;
extern vm_page_t bogus_page;
#ifdef DIAGNOSTIC
/*
* Set to 1 if reads of block zero should cause readahead to be done.
* Set to 0 treats a read of block zero as a non-sequential read.
*
* Setting to one assumes that most reads of block zero of files are due to
* sequential passes over the files (e.g. cat, sum) where additional blocks
* will soon be needed. Setting to zero assumes that the majority are
* surgical strikes to get particular info (e.g. size, file) where readahead
* blocks will not be used and, in fact, push out other potentially useful
* blocks from the cache. The former seems intuitive, but some quick tests
* showed that the latter performed better from a system-wide point of view.
*/
int doclusterraz = 0;
#define ISSEQREAD(vp, blk) \
(((blk) != 0 || doclusterraz) && \
((blk) == (vp)->v_lastr + 1 || (blk) == (vp)->v_lastr))
#else
#define ISSEQREAD(vp, blk) \
(/* (blk) != 0 && */ ((blk) == (vp)->v_lastr + 1 || (blk) == (vp)->v_lastr))
#endif
/*
* allow for three entire read-aheads... The system will
* adjust downwards rapidly if needed...
*/
#define RA_MULTIPLE_FAST 2
#define RA_MULTIPLE_SLOW 3
#define RA_SHIFTDOWN 1 /* approx lg2(RA_MULTIPLE) */
/*
* This replaces bread. If this is a bread at the beginning of a file and
* lastr is 0, we assume this is the first read and we'll read up to two
* blocks if they are sequential. After that, we'll do regular read ahead
* in clustered chunks.
* bp is the block requested.
* rbp is the read-ahead block.
* If either is NULL, then you don't have to do the I/O.
*/
int
cluster_read(vp, filesize, lblkno, size, cred, bpp)
struct vnode *vp;
u_quad_t filesize;
daddr_t lblkno;
long size;
struct ucred *cred;
struct buf **bpp;
{
struct buf *bp, *rbp;
daddr_t blkno, rablkno, origlblkno;
int error, num_ra, alreadyincore;
int i;
int seq;
error = 0;
/*
* get the requested block
*/
origlblkno = lblkno;
*bpp = bp = getblk(vp, lblkno, size, 0, 0);
seq = ISSEQREAD(vp, lblkno);
/*
* if it is in the cache, then check to see if the reads have been
* sequential. If they have, then try some read-ahead, otherwise
* back-off on prospective read-aheads.
*/
if (bp->b_flags & B_CACHE) {
if (!seq) {
vp->v_maxra = bp->b_lblkno + bp->b_bcount / size;
vp->v_ralen >>= RA_SHIFTDOWN;
return 0;
} else if( vp->v_maxra > lblkno) {
if ( (vp->v_maxra + (vp->v_ralen / RA_MULTIPLE_SLOW)) >= (lblkno + vp->v_ralen)) {
if ((vp->v_ralen + 1) < RA_MULTIPLE_FAST*(MAXPHYS / size))
++vp->v_ralen;
return 0;
}
lblkno = vp->v_maxra;
} else {
lblkno += 1;
}
bp = NULL;
} else {
/*
* if it isn't in the cache, then get a chunk from disk if
* sequential, otherwise just get the block.
*/
bp->b_flags |= B_READ;
lblkno += 1;
curproc->p_stats->p_ru.ru_inblock++; /* XXX */
vp->v_ralen = 0;
}
/*
* assume no read-ahead
*/
alreadyincore = 1;
rablkno = lblkno;
/*
* if we have been doing sequential I/O, then do some read-ahead
*/
if (seq) {
/*
* bump ralen a bit...
*/
if ((vp->v_ralen + 1) < RA_MULTIPLE_SLOW*(MAXPHYS / size))
++vp->v_ralen;
/*
* this code makes sure that the stuff that we have read-ahead
* is still in the cache. If it isn't, we have been reading
* ahead too much, and we need to back-off, otherwise we might
* try to read more.
*/
for (i = 0; i < vp->v_ralen; i++) {
rablkno = lblkno + i;
alreadyincore = (int) incore(vp, rablkno);
if (!alreadyincore) {
if (inmem(vp, rablkno)) {
if (vp->v_maxra < rablkno)
vp->v_maxra = rablkno + 1;
continue;
}
if (rablkno < vp->v_maxra) {
vp->v_maxra = rablkno;
vp->v_ralen >>= RA_SHIFTDOWN;
alreadyincore = 1;
}
break;
} else if (vp->v_maxra < rablkno) {
vp->v_maxra = rablkno + 1;
}
}
}
/*
* we now build the read-ahead buffer if it is desirable.
*/
rbp = NULL;
if (!alreadyincore &&
(rablkno + 1) * size <= filesize &&
!(error = VOP_BMAP(vp, rablkno, NULL, &blkno, &num_ra, NULL)) &&
blkno != -1) {
if (num_ra > vp->v_ralen)
num_ra = vp->v_ralen;
if (num_ra) {
rbp = cluster_rbuild(vp, filesize, rablkno, blkno, size,
num_ra + 1);
} else {
rbp = getblk(vp, rablkno, size, 0, 0);
rbp->b_flags |= B_READ | B_ASYNC;
rbp->b_blkno = blkno;
}
}
/*
* handle the synchronous read
*/
if (bp) {
if (bp->b_flags & (B_DONE | B_DELWRI))
panic("cluster_read: DONE bp");
else {
vfs_busy_pages(bp, 0);
error = VOP_STRATEGY(bp);
vp->v_maxra = bp->b_lblkno + bp->b_bcount / size;
totreads++;
totreadblocks += bp->b_bcount / size;
curproc->p_stats->p_ru.ru_inblock++;
}
}
/*
* and if we have read-aheads, do them too
*/
if (rbp) {
vp->v_maxra = rbp->b_lblkno + rbp->b_bcount / size;
if (error || (rbp->b_flags & B_CACHE)) {
rbp->b_flags &= ~(B_ASYNC | B_READ);
brelse(rbp);
} else {
if ((rbp->b_flags & B_CLUSTER) == 0)
vfs_busy_pages(rbp, 0);
(void) VOP_STRATEGY(rbp);
totreads++;
totreadblocks += rbp->b_bcount / size;
curproc->p_stats->p_ru.ru_inblock++;
}
}
if (bp && ((bp->b_flags & B_ASYNC) == 0))
return (biowait(bp));
return (error);
}
/*
* If blocks are contiguous on disk, use this to provide clustered
* read ahead. We will read as many blocks as possible sequentially
* and then parcel them up into logical blocks in the buffer hash table.
*/
static struct buf *
cluster_rbuild(vp, filesize, lbn, blkno, size, run)
struct vnode *vp;
u_quad_t filesize;
daddr_t lbn;
daddr_t blkno;
long size;
int run;
{
struct buf *bp, *tbp;
daddr_t bn;
int i, inc, j;
#ifdef DIAGNOSTIC
if (size != vp->v_mount->mnt_stat.f_iosize)
panic("cluster_rbuild: size %d != filesize %d\n",
size, vp->v_mount->mnt_stat.f_iosize);
#endif
if (size * (lbn + run) > filesize)
--run;
tbp = getblk(vp, lbn, size, 0, 0);
if (tbp->b_flags & B_CACHE)
return tbp;
tbp->b_blkno = blkno;
tbp->b_flags |= B_ASYNC | B_READ;
if( ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) )
return tbp;
bp = trypbuf();
if (bp == 0)
return tbp;
(vm_offset_t) bp->b_data |= ((vm_offset_t) tbp->b_data) & PAGE_MASK;
bp->b_flags = B_ASYNC | B_READ | B_CALL | B_BUSY | B_CLUSTER | B_VMIO;
bp->b_iodone = cluster_callback;
bp->b_blkno = blkno;
bp->b_lblkno = lbn;
pbgetvp(vp, bp);
TAILQ_INIT(&bp->b_cluster.cluster_head);
bp->b_bcount = 0;
bp->b_bufsize = 0;
bp->b_npages = 0;
inc = btodb(size);
for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
if (i != 0) {
if ((bp->b_npages * PAGE_SIZE) + size > MAXPHYS)
break;
if (incore(vp, lbn + i))
break;
tbp = getblk(vp, lbn + i, size, 0, 0);
if ((tbp->b_flags & B_CACHE) ||
(tbp->b_flags & B_VMIO) == 0) {
brelse(tbp);
break;
}
for (j=0;j<tbp->b_npages;j++) {
if (tbp->b_pages[j]->valid) {
break;
}
}
if (j != tbp->b_npages) {
/*
* force buffer to be re-constituted later
*/
tbp->b_flags |= B_RELBUF;
brelse(tbp);
break;
}
tbp->b_flags |= B_READ | B_ASYNC;
if( tbp->b_blkno == tbp->b_lblkno) {
tbp->b_blkno = bn;
} else if (tbp->b_blkno != bn) {
brelse(tbp);
break;
}
}
TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
tbp, b_cluster.cluster_entry);
for (j = 0; j < tbp->b_npages; j += 1) {
vm_page_t m;
m = tbp->b_pages[j];
++m->busy;
++m->object->paging_in_progress;
if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) {
m = bogus_page;
}
if ((bp->b_npages == 0) ||
(bp->b_pages[bp->b_npages-1] != m)) {
bp->b_pages[bp->b_npages] = m;
bp->b_npages++;
}
}
bp->b_bcount += tbp->b_bcount;
bp->b_bufsize += tbp->b_bufsize;
}
pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
(vm_page_t *)bp->b_pages, bp->b_npages);
return (bp);
}
/*
* Cleanup after a clustered read or write.
* This is complicated by the fact that any of the buffers might have
* extra memory (if there were no empty buffer headers at allocbuf time)
* that we will need to shift around.
*/
void
cluster_callback(bp)
struct buf *bp;
{
struct buf *nbp, *tbp;
int error = 0;
/*
* Must propogate errors to all the components.
*/
if (bp->b_flags & B_ERROR)
error = bp->b_error;
pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages);
/*
* Move memory from the large cluster buffer into the component
* buffers and mark IO as done on these.
*/
for (tbp = bp->b_cluster.cluster_head.tqh_first;
tbp; tbp = nbp) {
nbp = tbp->b_cluster.cluster_entry.tqe_next;
if (error) {
tbp->b_flags |= B_ERROR;
tbp->b_error = error;
}
biodone(tbp);
}
relpbuf(bp);
}
/*
* Do clustered write for FFS.
*
* Three cases:
* 1. Write is not sequential (write asynchronously)
* Write is sequential:
* 2. beginning of cluster - begin cluster
* 3. middle of a cluster - add to cluster
* 4. end of a cluster - asynchronously write cluster
*/
void
cluster_write(bp, filesize)
struct buf *bp;
u_quad_t filesize;
{
struct vnode *vp;
daddr_t lbn;
int maxclen, cursize;
int lblocksize;
int async;
vp = bp->b_vp;
async = (vp->v_mount && (vp->v_mount->mnt_flag & MNT_ASYNC));
lblocksize = vp->v_mount->mnt_stat.f_iosize;
lbn = bp->b_lblkno;
/* Initialize vnode to beginning of file. */
if (lbn == 0)
vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
(bp->b_blkno != vp->v_lasta + btodb(lblocksize))) {
maxclen = MAXPHYS / lblocksize - 1;
if (vp->v_clen != 0) {
/*
* Next block is not sequential.
*
* If we are not writing at end of file, the process
* seeked to another point in the file since its last
* write, or we have reached our maximum cluster size,
* then push the previous cluster. Otherwise try
* reallocating to make it sequential.
*/
cursize = vp->v_lastw - vp->v_cstart + 1;
#if 1
if ((lbn + 1) * lblocksize != filesize ||
lbn != vp->v_lastw + 1 ||
vp->v_clen <= cursize) {
if (!async)
cluster_wbuild(vp, lblocksize,
vp->v_cstart, cursize);
}
#else
if (!doreallocblks ||
(lbn + 1) * lblocksize != filesize ||
lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
if (!async)
cluster_wbuild(vp, lblocksize,
vp->v_cstart, cursize);
} else {
struct buf **bpp, **endbp;
struct cluster_save *buflist;
buflist = cluster_collectbufs(vp, bp);
endbp = &buflist->bs_children
[buflist->bs_nchildren - 1];
if (VOP_REALLOCBLKS(vp, buflist)) {
/*
* Failed, push the previous cluster.
*/
for (bpp = buflist->bs_children;
bpp < endbp; bpp++)
brelse(*bpp);
free(buflist, M_SEGMENT);
cluster_wbuild(vp, lblocksize,
vp->v_cstart, cursize);
} else {
/*
* Succeeded, keep building cluster.
*/
for (bpp = buflist->bs_children;
bpp <= endbp; bpp++)
bdwrite(*bpp);
free(buflist, M_SEGMENT);
vp->v_lastw = lbn;
vp->v_lasta = bp->b_blkno;
return;
}
}
#endif
}
/*
* Consider beginning a cluster. If at end of file, make
* cluster as large as possible, otherwise find size of
* existing cluster.
*/
if ((lbn + 1) * lblocksize != filesize &&
(bp->b_blkno == bp->b_lblkno) &&
(VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) ||
bp->b_blkno == -1)) {
bawrite(bp);
vp->v_clen = 0;
vp->v_lasta = bp->b_blkno;
vp->v_cstart = lbn + 1;
vp->v_lastw = lbn;
return;
}
vp->v_clen = maxclen;
if (!async && maxclen == 0) { /* I/O not contiguous */
vp->v_cstart = lbn + 1;
bawrite(bp);
} else { /* Wait for rest of cluster */
vp->v_cstart = lbn;
bdwrite(bp);
}
} else if (lbn == vp->v_cstart + vp->v_clen) {
/*
* At end of cluster, write it out.
*/
bdwrite(bp);
cluster_wbuild(vp, lblocksize, vp->v_cstart,
vp->v_clen + 1);
vp->v_clen = 0;
vp->v_cstart = lbn + 1;
} else
/*
* In the middle of a cluster, so just delay the I/O for now.
*/
bdwrite(bp);
vp->v_lastw = lbn;
vp->v_lasta = bp->b_blkno;
}
/*
* This is an awful lot like cluster_rbuild...wish they could be combined.
* The last lbn argument is the current block on which I/O is being
* performed. Check to see that it doesn't fall in the middle of
* the current block (if last_bp == NULL).
*/
void
cluster_wbuild(vp, size, start_lbn, len)
struct vnode *vp;
long size;
daddr_t start_lbn;
int len;
{
struct buf *bp, *tbp;
int i, j, s;
int dbsize = btodb(size);
int origlen = len;
redo:
if (len == 0)
return;
if ( ((tbp = incore(vp, start_lbn)) == NULL) ||
((tbp->b_flags & (B_INVAL|B_BUSY|B_DELWRI)) != B_DELWRI)) {
++start_lbn;
--len;
goto redo;
}
tbp = getblk(vp, start_lbn, size, 0, 0);
if ((tbp->b_flags & B_DELWRI) == 0) {
++start_lbn;
--len;
brelse(tbp);
goto redo;
}
/*
* Extra memory in the buffer, punt on this buffer. XXX we could
* handle this in most cases, but we would have to push the extra
* memory down to after our max possible cluster size and then
* potentially pull it back up if the cluster was terminated
* prematurely--too much hassle.
*/
if (((tbp->b_flags & (B_VMIO|B_CLUSTEROK)) != (B_VMIO|B_CLUSTEROK)) ||
(tbp->b_bcount != tbp->b_bufsize) ||
len == 1) {
bawrite(tbp);
++start_lbn;
--len;
goto redo;
}
bp = trypbuf();
if (bp == NULL) {
bawrite(tbp);
++start_lbn;
--len;
goto redo;
}
TAILQ_INIT(&bp->b_cluster.cluster_head);
bp->b_bcount = 0;
bp->b_bufsize = 0;
bp->b_npages = 0;
bp->b_blkno = tbp->b_blkno;
bp->b_lblkno = tbp->b_lblkno;
(vm_offset_t) bp->b_data |= ((vm_offset_t) tbp->b_data) & PAGE_MASK;
bp->b_flags |= B_CALL | B_BUSY | B_CLUSTER;
bp->b_iodone = cluster_callback;
pbgetvp(vp, bp);
for (i = 0; i < len; ++i, ++start_lbn) {
if (i != 0) {
s = splbio();
if ((tbp = incore(vp, start_lbn)) == NULL) {
splx(s);
break;
}
if ((tbp->b_flags & (B_CLUSTEROK|B_INVAL|B_BUSY|B_DELWRI)) != (B_DELWRI|B_CLUSTEROK)) {
splx(s);
break;
}
if ((tbp->b_bcount != size) ||
((bp->b_blkno + dbsize * i) != tbp->b_blkno) ||
((tbp->b_npages + bp->b_npages) > (MAXPHYS / PAGE_SIZE))) {
splx(s);
break;
}
bremfree(tbp);
tbp->b_flags |= B_BUSY;
tbp->b_flags &= ~B_DONE;
splx(s);
}
for (j = 0; j < tbp->b_npages; j += 1) {
vm_page_t m;
m = tbp->b_pages[j];
++m->busy;
++m->object->paging_in_progress;
if ((bp->b_npages == 0) ||
(bp->b_pages[bp->b_npages - 1] != m)) {
bp->b_pages[bp->b_npages] = m;
bp->b_npages++;
}
}
bp->b_bcount += size;
bp->b_bufsize += size;
tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
tbp->b_flags |= B_ASYNC;
s = splbio();
reassignbuf(tbp, tbp->b_vp); /* put on clean list */
++tbp->b_vp->v_numoutput;
splx(s);
TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head,
tbp, b_cluster.cluster_entry);
}
pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
(vm_page_t *) bp->b_pages, bp->b_npages);
bawrite(bp);
len -= i;
goto redo;
}
#if 0
/*
* Collect together all the buffers in a cluster.
* Plus add one additional buffer.
*/
struct cluster_save *
cluster_collectbufs(vp, last_bp)
struct vnode *vp;
struct buf *last_bp;
{
struct cluster_save *buflist;
daddr_t lbn;
int i, len;
len = vp->v_lastw - vp->v_cstart + 1;
buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
M_SEGMENT, M_WAITOK);
buflist->bs_nchildren = 0;
buflist->bs_children = (struct buf **) (buflist + 1);
for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++)
(void) bread(vp, lbn, last_bp->b_bcount, NOCRED,
&buflist->bs_children[i]);
buflist->bs_children[i] = last_bp;
buflist->bs_nchildren = i + 1;
return (buflist);
}
#endif