/*- * 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 1.17 1995/06/28 12:31:47 davidg Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DEBUG #include #include int doreallocblks = 0; struct ctldebug debug13 = {"doreallocblks", &doreallocblks}; #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; long flags; 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)) { struct buf *bpt; 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 cluster_save *b_save; 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 + 1) > 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); b_save = malloc(sizeof(struct buf *) * run + sizeof(struct cluster_save), M_SEGMENT, M_WAITOK); b_save->bs_nchildren = 0; b_save->bs_children = (struct buf **) (b_save + 1); bp->b_saveaddr = b_save; 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;jb_npages;j++) { if (tbp->b_pages[j]->valid) { break; } } if (j != tbp->b_npages) { 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; } } ++b_save->bs_nchildren; b_save->bs_children[i] = tbp; 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) { 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 cluster_save *b_save; struct buf **bpp, *tbp; caddr_t cp; int error = 0; /* * Must propogate errors to all the components. */ if (bp->b_flags & B_ERROR) error = bp->b_error; b_save = (struct cluster_save *) (bp->b_saveaddr); 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 (bpp = b_save->bs_children; b_save->bs_nchildren--; ++bpp) { tbp = *bpp; if (error) { tbp->b_flags |= B_ERROR; tbp->b_error = error; } biodone(tbp); } free(b_save, M_SEGMENT); 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; vp = bp->b_vp; 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 (!doreallocblks || (lbn + 1) * lblocksize != filesize || lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { cluster_wbuild(vp, NULL, lblocksize, vp->v_cstart, cursize, lbn); } 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, NULL, lblocksize, vp->v_cstart, cursize, lbn); } 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; } } } /* * 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 (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. */ cluster_wbuild(vp, bp, bp->b_bcount, vp->v_cstart, vp->v_clen + 1, lbn); 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, last_bp, size, start_lbn, len, lbn) struct vnode *vp; struct buf *last_bp; long size; daddr_t start_lbn; int len; daddr_t lbn; { struct cluster_save *b_save; struct buf *bp, *tbp, *pb; caddr_t cp; int i, j, s; #ifdef DIAGNOSTIC if (size != vp->v_mount->mnt_stat.f_iosize) panic("cluster_wbuild: size %d != filesize %d\n", size, vp->v_mount->mnt_stat.f_iosize); #endif redo: if( (lbn != -1) || (last_bp == 0)) { while ((!(tbp = incore(vp, start_lbn)) || (tbp->b_flags & B_BUSY) || (start_lbn == lbn)) && len) { ++start_lbn; --len; } pb = trypbuf(); /* Get more memory for current buffer */ if (len <= 1 || pb == NULL) { if (pb != NULL) relpbuf(pb); if (last_bp) { bawrite(last_bp); } else if (len) { bp = getblk(vp, start_lbn, size, 0, 0); bawrite(bp); } return; } tbp = getblk(vp, start_lbn, size, 0, 0); } else { tbp = last_bp; if( tbp->b_flags & B_BUSY) { printf("vfs_cluster: warning: buffer already busy\n"); } tbp->b_flags |= B_BUSY; last_bp = 0; pb = trypbuf(); if (pb == NULL) { bawrite(tbp); return; } } if (!(tbp->b_flags & B_DELWRI)) { relpbuf(pb); ++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_bcount != tbp->b_bufsize) { relpbuf(pb); ++start_lbn; --len; bawrite(tbp); goto redo; } bp = pb; b_save = malloc(sizeof(struct buf *) * (len + 1) + sizeof(struct cluster_save), M_SEGMENT, M_WAITOK); b_save->bs_nchildren = 0; b_save->bs_children = (struct buf **) (b_save + 1); bp->b_saveaddr = b_save; bp->b_bcount = 0; bp->b_bufsize = 0; bp->b_npages = 0; if (tbp->b_flags & B_VMIO) bp->b_flags |= B_VMIO; 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) { /* * Block is not in core or the non-sequential block * ending our cluster was part of the cluster (in * which case we don't want to write it twice). */ if (!(tbp = incore(vp, start_lbn)) || (last_bp == NULL && start_lbn == lbn)) break; if ((tbp->b_flags & (B_INVAL | B_CLUSTEROK)) != B_CLUSTEROK) break; if ((tbp->b_npages + bp->b_npages) > (MAXPHYS / PAGE_SIZE)) break; if ( (tbp->b_blkno != tbp->b_lblkno) && ((bp->b_blkno + btodb(size) * i) != tbp->b_blkno)) break; /* * Get the desired block buffer (unless it is the * final sequential block whose buffer was passed in * explictly as last_bp). */ if (last_bp == NULL || start_lbn != lbn) { if( tbp->b_flags & B_BUSY) break; tbp = getblk(vp, start_lbn, size, 0, 0); if (!(tbp->b_flags & B_DELWRI) || ((tbp->b_flags & B_VMIO) != (bp->b_flags & B_VMIO))) { brelse(tbp); break; } } else tbp = last_bp; } 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); b_save->bs_children[i] = tbp; } b_save->bs_nchildren = i; pmap_qenter(trunc_page((vm_offset_t) bp->b_data), (vm_page_t *) bp->b_pages, bp->b_npages); bawrite(bp); if (i < len) { len -= i; goto redo; } } /* * 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); }