Module Name: src
Committed By: mlelstv
Date: Fri Dec 25 09:28:56 UTC 2020
Modified Files:
src/sys/miscfs/specfs: spec_vnops.c
Log Message:
When reading from a block device, queue parallel block requests to
fill a buffer with breadn.
To generate a diff of this commit:
cvs rdiff -u -r1.180 -r1.181 src/sys/miscfs/specfs/spec_vnops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/miscfs/specfs/spec_vnops.c
diff -u src/sys/miscfs/specfs/spec_vnops.c:1.180 src/sys/miscfs/specfs/spec_vnops.c:1.181
--- src/sys/miscfs/specfs/spec_vnops.c:1.180 Sat Jun 27 17:29:19 2020
+++ src/sys/miscfs/specfs/spec_vnops.c Fri Dec 25 09:28:56 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: spec_vnops.c,v 1.180 2020/06/27 17:29:19 christos Exp $ */
+/* $NetBSD: spec_vnops.c,v 1.181 2020/12/25 09:28:56 mlelstv Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.180 2020/06/27 17:29:19 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: spec_vnops.c,v 1.181 2020/12/25 09:28:56 mlelstv Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@@ -695,6 +695,10 @@ spec_read(void *v)
struct partinfo pi;
int n, on;
int error = 0;
+ int i, nra;
+ daddr_t lastbn, *rablks;
+ int *rasizes;
+ int nrablks, ratogo;
KASSERT(uio->uio_rw == UIO_READ);
KASSERTMSG(VMSPACE_IS_KERNEL_P(uio->uio_vmspace) ||
@@ -723,18 +727,45 @@ spec_read(void *v)
bsize = BLKDEV_IOSIZE;
bscale = bsize >> DEV_BSHIFT;
+
+ nra = uimax(16 * MAXPHYS / bsize - 1, 511);
+ rablks = kmem_alloc(nra * sizeof(*rablks), KM_SLEEP);
+ rasizes = kmem_alloc(nra * sizeof(*rasizes), KM_SLEEP);
+ lastbn = ((uio->uio_offset + uio->uio_resid - 1) >> DEV_BSHIFT)
+ &~ (bscale - 1);
+ nrablks = ratogo = 0;
do {
bn = (uio->uio_offset >> DEV_BSHIFT) &~ (bscale - 1);
on = uio->uio_offset % bsize;
n = uimin((unsigned)(bsize - on), uio->uio_resid);
- error = bread(vp, bn, bsize, 0, &bp);
- if (error) {
- return (error);
+
+ if (ratogo == 0) {
+ nrablks = uimin((lastbn - bn) / bscale, nra);
+ ratogo = nrablks;
+
+ for (i = 0; i < nrablks; ++i) {
+ rablks[i] = bn + (i+1) * bscale;
+ rasizes[i] = bsize;
+ }
+
+ error = breadn(vp, bn, bsize,
+ rablks, rasizes, nrablks,
+ 0, &bp);
+ } else {
+ if (ratogo > 0)
+ --ratogo;
+ error = bread(vp, bn, bsize, 0, &bp);
}
+ if (error)
+ break;
n = uimin(n, bsize - bp->b_resid);
error = uiomove((char *)bp->b_data + on, n, uio);
brelse(bp, 0);
} while (error == 0 && uio->uio_resid > 0 && n != 0);
+
+ kmem_free(rablks, nra * sizeof(*rablks));
+ kmem_free(rasizes, nra * sizeof(*rasizes));
+
return (error);
default:
