Minor performance enhancements from NetBSD

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 33ad1ca..ffa423f 100644 (file)
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vfs_bio.c,v 1.13 1997/01/05 11:09:01 niklas Exp $     */
+/*     $OpenBSD: vfs_bio.c,v 1.14 1997/04/14 04:23:23 tholo Exp $      */
 /*     $NetBSD: vfs_bio.c,v 1.44 1996/06/11 11:15:36 pk Exp $  */
 
 /*-
@@ -602,6 +602,20 @@ brelse(bp)
        if (ISSET(bp->b_flags, (B_NOCACHE|B_ERROR)))
                SET(bp->b_flags, B_INVAL);
 
+       if (ISSET(bp->b_flags, B_VFLUSH)) {
+               /*
+                * This is a delayed write buffer that was just flushed to
+                * disk.  It is still on the LRU queue.  If it's become
+                * invalid, then we need to move it to a different queue;
+                * otherwise leave it in its current position.
+                */
+               CLR(bp->b_flags, B_VFLUSH);
+               if (!ISSET(bp->b_flags, B_ERROR|B_INVAL|B_LOCKED|B_AGE))
+                       goto already_queued;
+               else
+                       bremfree(bp);
+       }
+
        if ((bp->b_bufsize <= 0) || ISSET(bp->b_flags, B_INVAL)) {
                /*
                 * If it's invalid or empty, dissociate it from its vnode
@@ -636,6 +650,7 @@ brelse(bp)
                binstailfree(bp, bufq);
        }
 
+already_queued:
        /* Unlock the buffer. */
        CLR(bp->b_flags, (B_AGE | B_ASYNC | B_BUSY | B_NOCACHE));
 
@@ -870,13 +885,30 @@ start:
                return (0);
        }
 
+       if (ISSET(bp->b_flags, B_VFLUSH)) {
+               /*
+                * This is a delayed write buffer being flushed to disk.  Make
+                * sure it gets aged out of the queue when it's finished, and
+                * leave it off the LRU queue.
+                */
+               CLR(bp->b_flags, B_VFLUSH);
+               SET(bp->b_flags, B_AGE);
+               splx(s);
+               goto start;
+       }
+
        /* Buffer is no longer on free lists. */
        SET(bp->b_flags, B_BUSY);
 
        /* If buffer was a delayed write, start it, and go back to the top. */
        if (ISSET(bp->b_flags, B_DELWRI)) {
                splx(s);
-               bawrite (bp);
+               /*
+                * This buffer has gone through the LRU, so make sure it gets
+                * reused ASAP.
+                */
+               SET(bp->b_flags, B_AGE);
+               bawrite(bp);
                goto start;
        }
 

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 2c05c9f..0d2ac94 100644 (file)
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vfs_subr.c,v 1.8 1997/02/24 14:20:02 niklas Exp $     */
+/*     $OpenBSD: vfs_subr.c,v 1.9 1997/04/14 04:23:26 tholo Exp $      */
 /*     $NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $   */
 
 /*
@@ -467,8 +467,7 @@ vinvalbuf(vp, flags, cred, p, slpflag, slptimeo)
                                        return (error);
                                break;
                        }
-                       bremfree(bp);
-                       bp->b_flags |= B_BUSY;
+                       bp->b_flags |= B_BUSY | B_VFLUSH;
                        splx(s);
                        /*
                         * XXX Since there are no node locks for NFS, I believe
@@ -505,8 +504,7 @@ loop:
                        continue;
                if ((bp->b_flags & B_DELWRI) == 0)
                        panic("vflushbuf: not dirty");
-               bremfree(bp);
-               bp->b_flags |= B_BUSY;
+               bp->b_flags |= B_BUSY | B_VFLUSH;
                splx(s);
                /*
                 * Wait for I/O associated with indirect blocks to complete,

diff --git a/sys/sys/buf.h b/sys/sys/buf.h
index 888eca3..c96a71a 100644 (file)
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -1,5 +1,5 @@
-/*     $OpenBSD: buf.h,v 1.5 1996/06/11 03:25:14 tholo Exp $   */
-/*     $NetBSD: buf.h,v 1.24 1996/02/18 11:55:45 fvdl Exp $    */
+/*     $OpenBSD: buf.h,v 1.6 1997/04/14 04:23:21 tholo Exp $   */
+/*     $NetBSD: buf.h,v 1.25 1997/04/09 21:12:17 mycroft Exp $ */
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -124,6 +124,7 @@ struct buf {
 #define        B_WRITE         0x00000000      /* Write buffer (pseudo flag). */
 #define        B_WRITEINPROG   0x01000000      /* Write in progress. */
 #define        B_XXX           0x02000000      /* Debugging flag. */
+#define        B_VFLUSH        0x04000000      /* Buffer is being synced. */
 
 /*
  * This structure describes a clustered I/O.  It is stored in the b_saveaddr