diff options
author | dyson <dyson@FreeBSD.org> | 1995-11-23 07:24:41 +0000 |
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committer | dyson <dyson@FreeBSD.org> | 1995-11-23 07:24:41 +0000 |
commit | 711711e9f3d02ef8f5958392d4774ca0baddadb9 (patch) | |
tree | 6a96e9d2332ea78c99473115ebf81d080f0536cd /sys/ufs | |
parent | 262d14803690c3c8f394da8917b4a04d8f187c70 (diff) | |
download | FreeBSD-src-711711e9f3d02ef8f5958392d4774ca0baddadb9.zip FreeBSD-src-711711e9f3d02ef8f5958392d4774ca0baddadb9.tar.gz |
Update the wd.c driver to use the new TAILQ scheme for device
buffer queue. Also, create a new subroutine 'tqdisksort' that
is an improved version of the original disksort that also uses
TAILQs.
Diffstat (limited to 'sys/ufs')
-rw-r--r-- | sys/ufs/ufs/ufs_disksubr.c | 95 |
1 files changed, 94 insertions, 1 deletions
diff --git a/sys/ufs/ufs/ufs_disksubr.c b/sys/ufs/ufs/ufs_disksubr.c index be8e81a..3598a69 100644 --- a/sys/ufs/ufs/ufs_disksubr.c +++ b/sys/ufs/ufs/ufs_disksubr.c @@ -36,7 +36,7 @@ * SUCH DAMAGE. * * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 - * $Id: ufs_disksubr.c,v 1.18 1995/08/28 16:09:11 bde Exp $ + * $Id: ufs_disksubr.c,v 1.19 1995/09/16 17:04:06 bde Exp $ */ #include <sys/param.h> @@ -69,6 +69,99 @@ #define b_cylinder b_resid void +tqdisksort(ap, bp) + struct buf_queue_head *ap; + register struct buf *bp; +{ + register struct buf *bq; + struct buf *bn; + + /* If the queue is empty, then it's easy. */ + if ((bq = ap->tqh_first) == NULL) { + TAILQ_INSERT_HEAD(ap, bp, b_act); + return; + } + +#if 1 + /* Put new writes after all reads */ + if ((bp->b_flags & B_READ) == 0) { + while (bn = bq->b_act.tqe_next) { + if ((bq->b_flags & B_READ) == 0) + break; + bq = bn; + } + } else { + while (bn = bq->b_act.tqe_next) { + if ((bq->b_flags & B_READ) == 0) { + if (ap->tqh_first != bq) { + bq = *bq->b_act.tqe_prev; + } + break; + } + bq = bn; + } + goto insert; + } +#endif + + /* + * If we lie after the first (currently active) request, then we + * must locate the second request list and add ourselves to it. + */ + if (bp->b_pblkno < bq->b_pblkno) { + while (bn = bq->b_act.tqe_next) { + /* + * Check for an ``inversion'' in the normally ascending + * cylinder numbers, indicating the start of the second + * request list. + */ + if (bn->b_pblkno < bq->b_pblkno) { + /* + * Search the second request list for the first + * request at a larger cylinder number. We go + * before that; if there is no such request, we + * go at end. + */ + do { + if (bp->b_pblkno < bn->b_pblkno) + goto insert; + bq = bn; + } while (bn = bq->b_act.tqe_next); + goto insert; /* after last */ + } + bq = bn; + } + /* + * No inversions... we will go after the last, and + * be the first request in the second request list. + */ + goto insert; + } + /* + * Request is at/after the current request... + * sort in the first request list. + */ + while (bn = bq->b_act.tqe_next) { + /* + * We want to go after the current request if there is an + * inversion after it (i.e. it is the end of the first + * request list), or if the next request is a larger cylinder + * than our request. + */ + if (bn->b_pblkno < bq->b_pblkno || + bp->b_pblkno < bn->b_pblkno) + goto insert; + bq = bn; + } + /* + * Neither a second list nor a larger request... we go at the end of + * the first list, which is the same as the end of the whole schebang. + */ +insert: + TAILQ_INSERT_AFTER(ap, bq, bp, b_act); +} + +void disksort(ap, bp) register struct buf *ap, *bp; { |