[src/trunk]: src/sys/arch/xen/xen Catch up with recent src/sys/dev/dksubr.c c...

[cl <cl%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3f3b2e6e822b
branches:  trunk
changeset: 565963:3f3b2e6e822b
user:      cl <cl%NetBSD.org@localhost>
date:      Sat Apr 24 16:47:29 2004 +0000

description:
Catch up with recent src/sys/dev/dksubr.c change (1.11 -> 1.12) which
prevents us from processing multiple bufs during 1 *start call.  We now
rely on dk_start calling us repeatedly as long as there are bufs on the
queue.

diffstat:

 sys/arch/xen/xen/xbd.c |  140 +++++++++++++++++++++++++-----------------------
 1 files changed, 73 insertions(+), 67 deletions(-)

diffs (176 lines):

diff -r ad3faa1d8487 -r 3f3b2e6e822b sys/arch/xen/xen/xbd.c
--- a/sys/arch/xen/xen/xbd.c    Sat Apr 24 15:49:00 2004 +0000
+++ b/sys/arch/xen/xen/xbd.c    Sat Apr 24 16:47:29 2004 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: xbd.c,v 1.1 2004/04/17 12:56:27 cl Exp $ */
+/* $NetBSD: xbd.c,v 1.2 2004/04/24 16:47:29 cl Exp $ */
 
 /*
  *
@@ -33,7 +33,7 @@
 
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbd.c,v 1.1 2004/04/17 12:56:27 cl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbd.c,v 1.2 2004/04/24 16:47:29 cl Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -173,6 +173,8 @@
 static SIMPLEQ_HEAD(, xbdreq) xbdr_suspended =
        SIMPLEQ_HEAD_INITIALIZER(xbdr_suspended);
 
+#define        CANGET_XBDREQ() (!SLIST_EMPTY(&xbdreqs))
+
 #define        GET_XBDREQ(_xr) do {                            \
        (_xr) = SLIST_FIRST(&xbdreqs);                  \
        if (__predict_true(_xr))                        \
@@ -573,79 +575,83 @@
        struct xbdreq *pxr, *xr;
        struct  partition *pp;
        daddr_t bn;
+       int ret, runqueue;
 
        DPRINTF_FOLLOW(("xbdstart(%p, %p)\n", dksc, bp));
 
-       /* XXXcl:
-        * Normally dk_start processes the work queue for us, but we
-        * want to only signal Xen once we have queued as many
-        * requests as possible.
-        */
-       while ((bp = BUFQ_PEEK(&bufq)) != NULL) {
-               GETXBD_SOFTC(xs, bp->b_dev);
-               dksc = &xs->sc_dksc;
-               /* XXXrcd:
-                * Translate partition relative blocks to absolute blocks,
-                * this probably belongs (somehow) in dksubr.c, since it
-                * is independant of the underlying code...  This will require
-                * that the interface be expanded slightly, though.
-                */
-               bn = bp->b_blkno;
-               if (DISKPART(bp->b_dev) != RAW_PART) {
-                       pp = &xs->sc_dksc.sc_dkdev.dk_label->d_partitions[DISKPART(bp->b_dev)];
-                       bn += pp->p_offset;
-               }
-
-               DPRINTF(XBDB_IO, ("xbdstart: addr %p, sector %llu, "
-                   "count %ld [%s]\n", bp->b_data, (unsigned long long)bn,
-                   bp->b_bcount, bp->b_flags & B_READ ? "read" : "write"));
-
-               GET_XBDREQ(pxr);
-               if (__predict_false(pxr == NULL))
-                       break;
+       runqueue = 1;
+       ret = -1;
 
-               disk_busy(&dksc->sc_dkdev); /* XXX: put in dksubr.c */
-               /* we have a request slot, remove bp from the work queue */
-               (void) BUFQ_GET(&bufq);
-
-               pxr->xr_bp = bp;
-               pxr->xr_parent = pxr;
-               pxr->xr_bn = bn;
-               pxr->xr_bqueue = bp->b_bcount;
-               pxr->xr_bdone = bp->b_bcount;
-               pxr->xr_data = (vaddr_t)bp->b_data;
-               pxr->xr_sc = xs;
-
-               if (pxr->xr_data & (XEN_BSIZE - 1))
-                       map_align(pxr);
-
-               fill_ring(pxr);
-
-               while (__predict_false(pxr->xr_bqueue > 0)) {
-                       GET_XBDREQ(xr);
-                       if (__predict_false(xr == NULL))
-                               break;
-                       xr->xr_parent = pxr;
-                       fill_ring(xr);
-               }
-
-               if (__predict_false(pxr->xr_bqueue > 0)) {
-                       SIMPLEQ_INSERT_TAIL(&xbdr_suspended, pxr,
-                           xr_suspended);
-                       DPRINTF(XBDB_IO, ("xbdstart: suspended xbdreq %p "
-                           "for bp %p\n", pxr, bp));
-                       break;
-               }
+       GETXBD_SOFTC(xs, bp->b_dev);
+       dksc = &xs->sc_dksc;
+       /* XXXrcd:
+        * Translate partition relative blocks to absolute blocks,
+        * this probably belongs (somehow) in dksubr.c, since it
+        * is independant of the underlying code...  This will require
+        * that the interface be expanded slightly, though.
+        */
+       bn = bp->b_blkno;
+       if (DISKPART(bp->b_dev) != RAW_PART) {
+               pp = &xs->sc_dksc.sc_dkdev.dk_label->
+                       d_partitions[DISKPART(bp->b_dev)];
+               bn += pp->p_offset;
        }
 
-       if (blk_ring->req_prod != req_prod)
+       DPRINTF(XBDB_IO, ("xbdstart: addr %p, sector %llu, "
+           "count %ld [%s]\n", bp->b_data, (unsigned long long)bn,
+           bp->b_bcount, bp->b_flags & B_READ ? "read" : "write"));
+
+       GET_XBDREQ(pxr);
+       if (__predict_false(pxr == NULL))
+               goto out;
+
+       disk_busy(&dksc->sc_dkdev); /* XXX: put in dksubr.c */
+       /*
+        * We have a request slot, return 0 to make dk_start remove
+        * the bp from the work queue.
+        */
+       ret = 0;
+
+       pxr->xr_bp = bp;
+       pxr->xr_parent = pxr;
+       pxr->xr_bn = bn;
+       pxr->xr_bqueue = bp->b_bcount;
+       pxr->xr_bdone = bp->b_bcount;
+       pxr->xr_data = (vaddr_t)bp->b_data;
+       pxr->xr_sc = xs;
+
+       if (pxr->xr_data & (XEN_BSIZE - 1))
+               map_align(pxr);
+
+       fill_ring(pxr);
+
+       while (__predict_false(pxr->xr_bqueue > 0)) {
+               GET_XBDREQ(xr);
+               if (__predict_false(xr == NULL))
+                       break;
+               xr->xr_parent = pxr;
+               fill_ring(xr);
+       }
+
+       if (__predict_false(pxr->xr_bqueue > 0)) {
+               SIMPLEQ_INSERT_TAIL(&xbdr_suspended, pxr,
+                   xr_suspended);
+               DPRINTF(XBDB_IO, ("xbdstart: suspended xbdreq %p "
+                   "for bp %p\n", pxr, bp));
+       } else if (CANGET_XBDREQ() && BUFQ_PEEK(&bufq) != NULL) {
+               /* 
+                * We have enough resources to start another bp and
+                * there are additional bps on the queue, dk_start
+                * will call us again and we'll run the queue then.
+                */
+               runqueue = 0;
+       }
+
+ out:
+       if (runqueue && blk_ring->req_prod != req_prod)
                signal_requests_to_xen();
 
-       /* XXXcl:
-        * always signal -1 to dk_start since we have done all the
-        * work we can and dequeued all the requests we've handled.
-        */
-       return -1;
+       return ret;
 }
 
 static int