Ensure each nfsiod can actually enqueue more than one asynchio - this mirrors

the accidental situation that used to happen when it leaked buffers and allowed
the syncer to do it, however this puts a limit on how much of the buffer cache
it is allowed to consume to a sensible amount - improves nfs write performance
since we don't have to do tons of them synch now.

Modifies the existing code to use wakeup_one instead of cruft, and now
all nfsiod's tsleep the same way.

ok thib@ art@

1 files changed, 13 insertions, 14 deletions

diff --git a/sys/nfs/nfs_bio.c b/sys/nfs/nfs_bio.c
index e71beddf1a8..929152321e0 100644
--- a/sys/nfs/nfs_bio.c
+++ b/sys/nfs/nfs_bio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nfs_bio.c,v 1.50 2008/06/12 19:14:15 thib Exp $	*/
+/*	$OpenBSD: nfs_bio.c,v 1.51 2008/06/14 19:33:58 beck Exp $	*/
 /*	$NetBSD: nfs_bio.c,v 1.25.4.2 1996/07/08 20:47:04 jtc Exp $	*/
 
 /*
@@ -60,6 +60,7 @@ extern struct proc *nfs_iodwant[NFS_MAXASYNCDAEMON];
 extern int nfs_numasync;
 extern struct nfsstats nfsstats;
 struct nfs_bufqhead nfs_bufq;
+uint32_t nfs_bufqmax, nfs_bufqlen;
 
 /*
  * Vnode op for read using bio
@@ -545,24 +546,22 @@ int
 nfs_asyncio(bp)
 	struct buf *bp;
 {
-	int i;
-
 	if (nfs_numasync == 0)
 		goto out;
 
-	for (i = 0; i < NFS_MAXASYNCDAEMON; i++) {
-	    if (nfs_iodwant[i]) {
-		if ((bp->b_flags & B_READ) == 0) {
-			bp->b_flags |= B_WRITEINPROG;
-		}
-	
-		TAILQ_INSERT_TAIL(&nfs_bufq, bp, b_freelist);
-		nfs_iodwant[i] = (struct proc *)0;
-		wakeup((caddr_t)&nfs_iodwant[i]);
-		return (0);
-	    }
+	if (nfs_bufqlen > nfs_bufqmax)
+		goto out; /* too many bufs in use, force sync */
+
+	if ((bp->b_flags & B_READ) == 0) {
+		bp->b_flags |= B_WRITEINPROG;
 	}
 
+	TAILQ_INSERT_TAIL(&nfs_bufq, bp, b_freelist);
+	nfs_bufqlen++;
+
+	wakeup_one(&nfs_bufq);
+	return (0);
+
 out:
 	nfsstats.forcedsync++;
 	return (EIO);