Date: Mon, 7 Oct 2002 08:38:45 -0700 From: David Schultz <dschultz@uclink.Berkeley.EDU> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Peter Wemm <peter@wemm.org>, Sean Kelly <smkelly@zombie.org>, hackers@FreeBSD.ORG Subject: Re: swapoff? Message-ID: <20021007153845.GA371@HAL9000.homeunix.com> In-Reply-To: <200207131636.g6DGaoqh081285@apollo.backplane.com> References: <20020713071911.GA1558@HAL9000.wox.org> <20020713073404.9869A3811@overcee.wemm.org> <20020713115746.GA2162@HAL9000.wox.org> <200207131636.g6DGaoqh081285@apollo.backplane.com>
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I'm resurrecting this thread because I finally got around to
finishing up the patches to implement swapoff. I would appreciate
some review of them, particularly to verify that I have done the
right thing WRT synchronization. I have not optimized it to do
read clustering, but I have ensured that such an optimization
could be made. Other than that, I don't know of any deficiencies.
Index: include/unistd.h
===================================================================
RCS file: /home/ncvs/src/include/unistd.h,v
retrieving revision 1.60
diff -u -r1.60 unistd.h
--- include/unistd.h 2002/09/25 01:58:56 1.60
+++ include/unistd.h 2002/10/07 13:55:19
@@ -512,6 +512,7 @@
void setusershell(void);
int strtofflags(char **, u_long *, u_long *);
int swapon(const char *);
+int swapoff(const char *);
int syscall(int, ...);
off_t __syscall(quad_t, ...);
int ttyslot(void);
Index: lib/libc/sys/Makefile.inc
===================================================================
RCS file: /home/ncvs/src/lib/libc/sys/Makefile.inc,v
retrieving revision 1.96
diff -u -r1.96 Makefile.inc
--- lib/libc/sys/Makefile.inc 2002/10/02 18:01:51 1.96
+++ lib/libc/sys/Makefile.inc 2002/10/07 13:55:24
@@ -130,6 +130,7 @@
MLINKS+=stat.2 fstat.2 stat.2 lstat.2
MLINKS+=statfs.2 fstatfs.2
MLINKS+=syscall.2 __syscall.2
+MLINKS+=swapon.2 swapoff.2
MLINKS+=truncate.2 ftruncate.2
MLINKS+=utimes.2 futimes.2 utimes.2 lutimes.2
MLINKS+=wait.2 wait3.2 wait.2 wait4.2 wait.2 waitpid.2
Index: lib/libc/sys/swapon.2
===================================================================
RCS file: /home/ncvs/src/lib/libc/sys/swapon.2,v
retrieving revision 1.12
diff -u -r1.12 swapon.2
--- lib/libc/sys/swapon.2 2001/10/01 16:09:03 1.12
+++ lib/libc/sys/swapon.2 2002/10/07 13:55:24
@@ -36,14 +36,16 @@
.Dt SWAPON 2
.Os
.Sh NAME
-.Nm swapon
-.Nd add a swap device for interleaved paging/swapping
+.Nm swapon , swapoff
+.Nd control devices for interleaved paging/swapping
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn swapon "const char *special"
+.Ft int
+.Fn swapoff "const char *special"
.Sh DESCRIPTION
.Fn Swapon
makes the block device
@@ -55,13 +57,22 @@
.Fa special
is calculated at the time the device is first made available
for swapping.
+.Pp
+The
+.Fn swapoff
+system call disables paging and swapping on the given device.
+All associated swap metadata are deallocated, and the device
+is made available for other purposes.
.Sh RETURN VALUES
If an error has occurred, a value of -1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
-.Fn Swapon
-succeeds unless:
+Both
+.Fn swapon
+and
+.Fn swapoff
+can fail if:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
@@ -76,6 +87,19 @@
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EPERM
The caller is not the super-user.
+.It Bq Er EFAULT
+.Fa Special
+points outside the process's allocated address space.
+.El
+.Pp
+Additionally,
+.Fn swapon
+can fail for the following reasons:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The system has reached the boot-time limit on the number of
+swap devices,
+.Va vm.nswapdev .
.It Bq Er ENOTBLK
.Fa Special
is not a block device.
@@ -84,11 +108,6 @@
.Fa special
has already
been made available for swapping
-.It Bq Er EINVAL
-The device configured by
-.Fa special
-was not
-configured into the system as a swap device.
.It Bq Er ENXIO
The major device number of
.Fa special
@@ -96,20 +115,28 @@
for the associated hardware).
.It Bq Er EIO
An I/O error occurred while opening the swap device.
-.It Bq Er EFAULT
-.Fa Special
-points outside the process's allocated address space.
.El
+.Pp
+Lastly,
+.Fn swapoff
+can fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The system is not currently swapping to
+.Fa special .
+.It Bq Er ENOMEM
+Not enough virtual memory is available to safely disable
+paging and swapping to the given device.
+.El
.Sh SEE ALSO
.Xr config 8 ,
-.Xr swapon 8
-.Sh BUGS
-There is no way to stop swapping on a disk so that the pack may be
-dismounted.
-.Pp
-This call will be upgraded in future versions of the system.
+.Xr swapon 8 ,
+.Xr sysctl 8
.Sh HISTORY
The
.Fn swapon
function call appeared in
.Bx 4.0 .
+.Fn Swapoff
+appeared in
+.Fx 5.0 .
Index: sbin/swapon/Makefile
===================================================================
RCS file: /home/ncvs/src/sbin/swapon/Makefile,v
retrieving revision 1.6
diff -u -r1.6 Makefile
--- sbin/swapon/Makefile 2001/12/04 02:19:58 1.6
+++ sbin/swapon/Makefile 2002/10/07 13:55:33
@@ -3,5 +3,7 @@
PROG= swapon
MAN= swapon.8
+LINKS= ${BINDIR}/swapon ${BINDIR}/swapoff
+MLINKS= swapon.8 swapoff.8
.include <bsd.prog.mk>
Index: sbin/swapon/swapon.8
===================================================================
RCS file: /home/ncvs/src/sbin/swapon/swapon.8,v
retrieving revision 1.20
diff -u -r1.20 swapon.8
--- sbin/swapon/swapon.8 2002/08/21 18:11:44 1.20
+++ sbin/swapon/swapon.8 2002/10/07 13:55:33
@@ -36,39 +36,46 @@
.Dt SWAPON 8
.Os
.Sh NAME
-.Nm swapon
-.Nd "specify additional device for paging and swapping"
+.Nm swapon , swapoff
+.Nd "specify devices for paging and swapping"
.Sh SYNOPSIS
-.Nm
+.Nm swap[on|off]
.Fl a
-.Nm
+.Nm swap[on|off]
.Ar special_file ...
.Sh DESCRIPTION
The
-.Nm
+.Nm swapon
utility is used to specify additional devices on which paging and swapping
are to take place.
The system begins by swapping and paging on only a single device
so that only one disk is required at bootstrap time.
Calls to
-.Nm
+.Nm swapon
normally occur in the system multi-user initialization file
.Pa /etc/rc
making all swap devices available, so that the paging and swapping
activity is interleaved across several devices.
.Pp
+The
+.Nm swapoff
+utility disables paging and swapping on a device.
+Calls to
+.Nm swapoff
+succeed only if disabling the device would leave enough
+remaining virtual memory to accomodate all running programs.
+.Pp
Normally, the first form is used:
.Bl -tag -width indent
.It Fl a
All devices marked as ``sw''
swap devices in
.Pa /etc/fstab
-are made available unless their ``noauto'' option is also set.
+are added to or removed from the pool of available swap
+unless their ``noauto'' option is also set.
.El
.Pp
-The second form gives individual block devices as given
-in the system swap configuration table. The call makes only this space
-available to the system for swap allocation.
+The second form is used to configure or disable individual devices.
.Sh SEE ALSO
.Xr swapon 2 ,
.Xr fstab 5 ,
@@ -85,12 +92,12 @@
.It Pa /etc/fstab
ASCII file system description table
.El
-.Sh BUGS
-There is no way to stop paging and swapping on a device.
-It is therefore not possible to dismount swap devices which are
-mounted during system operation.
.Sh HISTORY
The
-.Nm
+.Nm swapon
utility appeared in
.Bx 4.0 .
+The
+.Nm swapoff
+utility appeared in
+.Fx 5.0 .
Index: sbin/swapon/swapon.c
===================================================================
RCS file: /home/ncvs/src/sbin/swapon/swapon.c,v
retrieving revision 1.12
diff -u -r1.12 swapon.c
--- sbin/swapon/swapon.c 2002/03/21 13:20:48 1.12
+++ sbin/swapon/swapon.c 2002/10/07 13:55:33
@@ -53,15 +53,21 @@
#include <string.h>
#include <unistd.h>
-static void usage(void);
-int add(char *name, int ignoreebusy);
+int do_swapoff;
+static void usage(const char *);
+static int this_is_swapoff(const char *);
+int twiddle(char *name, int ignoreebusy);
+
int
main(int argc, char **argv)
{
struct fstab *fsp;
int stat;
int ch, doall;
+ char *pname = argv[0];
+
+ do_swapoff = this_is_swapoff(pname);
doall = 0;
while ((ch = getopt(argc, argv, "a")) != -1)
@@ -71,7 +77,7 @@
break;
case '?':
default:
- usage();
+ usage(pname);
}
argv += optind;
@@ -82,23 +88,24 @@
continue;
if (strstr(fsp->fs_mntops, "noauto"))
continue;
- if (add(fsp->fs_spec, 1))
+ if (twiddle(fsp->fs_spec, 1))
stat = 1;
else
- printf("swapon: adding %s as swap device\n",
+ printf("%s: %sing %s as swap device\n",
+ pname, do_swapoff ? "remov" : "add",
fsp->fs_spec);
}
else if (!*argv)
- usage();
+ usage(pname);
for (; *argv; ++argv)
- stat |= add(*argv, 0);
+ stat |= twiddle(*argv, 0);
exit(stat);
}
int
-add(char *name, int ignoreebusy)
+twiddle(char *name, int ignoreebusy)
{
- if (swapon(name) == -1) {
+ if ((do_swapoff ? swapoff(name) : swapon(name)) == -1) {
switch (errno) {
case EBUSY:
if (!ignoreebusy)
@@ -114,8 +121,23 @@
}
static void
-usage()
+usage(const char *pname)
{
- fprintf(stderr, "usage: swapon [-a] [special_file ...]\n");
+ fprintf(stderr, "usage: %s [-a] [special_file ...]\n", pname);
exit(1);
+}
+
+static int
+this_is_swapoff(const char *s)
+{
+ const char *u;
+
+ if ((u = strrchr(s, '/')) != NULL)
+ ++u;
+ else
+ u = s;
+ if (strcmp(u, "swapoff") == 0)
+ return 1;
+ else
+ return 0;
}
Index: sys/kern/init_sysent.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/init_sysent.c,v
retrieving revision 1.135
diff -u -r1.135 init_sysent.c
--- sys/kern/init_sysent.c 2002/10/02 16:48:15 1.135
+++ sys/kern/init_sysent.c 2002/10/07 13:55:50
@@ -2,8 +2,8 @@
* System call switch table.
*
* DO NOT EDIT-- this file is automatically generated.
- * $FreeBSD: src/sys/kern/init_sysent.c,v 1.135 2002/10/02 16:48:15 archie Exp $
- * created from FreeBSD: src/sys/kern/syscalls.master,v 1.124 2002/10/01 02:35:59 rwatson Exp
+ * $FreeBSD$
+ * created from FreeBSD: src/sys/kern/syscalls.master,v 1.125 2002/10/02 16:48:15 archie Exp
*/
#include "opt_compat.h"
@@ -443,4 +443,5 @@
{ 0, (sy_call_t *)nosys }, /* 412 = extattr_set_link */
{ 0, (sy_call_t *)nosys }, /* 413 = extattr_get_link */
{ 0, (sy_call_t *)nosys }, /* 414 = extattr_delete_link */
+ { SYF_MPSAFE | AS(swapoff_args), (sy_call_t *)swapoff }, /* 415 = swapoff */
};
Index: sys/kern/subr_blist.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_blist.c,v
retrieving revision 1.10
diff -u -r1.10 subr_blist.c
--- sys/kern/subr_blist.c 2002/05/18 23:46:04 1.10
+++ sys/kern/subr_blist.c 2002/10/07 13:55:51
@@ -93,7 +93,7 @@
#include <stdlib.h>
#include <stdarg.h>
-#define malloc(a,b,c) malloc(a)
+#define malloc(a,b,c) calloc(a, 1)
#define free(a,b) free(a)
typedef unsigned int u_daddr_t;
@@ -116,6 +116,9 @@
daddr_t radix, int skip, daddr_t blk);
static void blst_copy(blmeta_t *scan, daddr_t blk, daddr_t radix,
daddr_t skip, blist_t dest, daddr_t count);
+static int blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count);
+static int blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count,
+ daddr_t radix, int skip, daddr_t blk);
static daddr_t blst_radix_init(blmeta_t *scan, daddr_t radix,
int skip, daddr_t count);
#ifndef _KERNEL
@@ -165,13 +168,14 @@
#if defined(BLIST_DEBUG)
printf(
- "BLIST representing %d blocks (%d MB of swap)"
- ", requiring %dK of ram\n",
- bl->bl_blocks,
- bl->bl_blocks * 4 / 1024,
- (bl->bl_rootblks * sizeof(blmeta_t) + 1023) / 1024
+ "BLIST representing %lld blocks (%lld MB of swap)"
+ ", requiring %lldK of ram\n",
+ (long long)bl->bl_blocks,
+ (long long)bl->bl_blocks * 4 / 1024,
+ (long long)(bl->bl_rootblks * sizeof(blmeta_t) + 1023) / 1024
);
- printf("BLIST raw radix tree contains %d records\n", bl->bl_rootblks);
+ printf("BLIST raw radix tree contains %lld records\n",
+ (long long)bl->bl_rootblks);
#endif
blst_radix_init(bl->bl_root, bl->bl_radix, bl->bl_skip, blocks);
@@ -226,6 +230,30 @@
}
/*
+ * blist_fill() - mark a region in the block bitmap as off-limits
+ * to the allocator (i.e. allocate it), ignoring any
+ * existing allocations. Return the number of blocks
+ * actually filled that were free before the call.
+ */
+
+int
+blist_fill(blist_t bl, daddr_t blkno, daddr_t count)
+{
+ int filled;
+
+ if (bl) {
+ if (bl->bl_radix == BLIST_BMAP_RADIX)
+ filled = blst_leaf_fill(bl->bl_root, blkno, count);
+ else
+ filled = blst_meta_fill(bl->bl_root, blkno, count,
+ bl->bl_radix, bl->bl_skip, 0);
+ bl->bl_free -= filled;
+ return filled;
+ } else
+ return 0;
+}
+
+/*
* blist_resize() - resize an existing radix tree to handle the
* specified number of blocks. This will reallocate
* the tree and transfer the previous bitmap to the new
@@ -507,9 +535,9 @@
int next_skip = (skip >> BLIST_META_RADIX_SHIFT);
#if 0
- printf("FREE (%x,%d) FROM (%x,%d)\n",
- freeBlk, count,
- blk, radix
+ printf("FREE (%llx,%lld) FROM (%llx,%lld)\n",
+ (long long)freeBlk, (long long)count,
+ (long long)blk, (long long)radix
);
#endif
@@ -679,6 +707,117 @@
}
/*
+ * BLST_LEAF_FILL() - allocate specific blocks in leaf bitmap
+ *
+ * This routine allocates all blocks in the specified range
+ * regardless of any existing allocations in that range. Returns
+ * the number of blocks allocated by the call.
+ */
+
+static int
+blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count)
+{
+ int n = blk & (BLIST_BMAP_RADIX - 1);
+ int nblks;
+ u_daddr_t mask, bitmap;
+
+ mask = ((u_daddr_t)-1 << n) &
+ ((u_daddr_t)-1 >> (BLIST_BMAP_RADIX - count - n));
+
+ /* Count the number of blocks we're about to allocate */
+ bitmap = scan->u.bmu_bitmap & mask;
+ for (nblks = 0; bitmap != 0; nblks++)
+ bitmap &= bitmap - 1;
+
+ scan->u.bmu_bitmap &= ~mask;
+ return nblks;
+}
+
+/*
+ * BLIST_META_FILL() - allocate specific blocks at a meta node
+ *
+ * This routine allocates the specified range of blocks,
+ * regardless of any existing allocations in the range. The
+ * range must be within the extent of this node. Returns the
+ * number of blocks allocated by the call.
+ */
+static int
+blst_meta_fill(
+ blmeta_t *scan,
+ daddr_t allocBlk,
+ daddr_t count,
+ daddr_t radix,
+ int skip,
+ daddr_t blk
+) {
+ int i;
+ int next_skip = (skip >> BLIST_META_RADIX_SHIFT);
+ int nblks = 0;
+
+ if (count == radix || scan->u.bmu_avail == 0) {
+ /*
+ * ALL-ALLOCATED special case
+ */
+ nblks = scan->u.bmu_avail;
+ scan->u.bmu_avail = 0;
+ scan->bm_bighint = count;
+ return nblks;
+ }
+
+ if (scan->u.bmu_avail == radix) {
+ radix >>= BLIST_META_RADIX_SHIFT;
+
+ /*
+ * ALL-FREE special case, initialize sublevel
+ */
+ for (i = 1; i <= skip; i += next_skip) {
+ if (scan[i].bm_bighint == (daddr_t)-1)
+ break;
+ if (next_skip == 1) {
+ scan[i].u.bmu_bitmap = (u_daddr_t)-1;
+ scan[i].bm_bighint = BLIST_BMAP_RADIX;
+ } else {
+ scan[i].bm_bighint = radix;
+ scan[i].u.bmu_avail = radix;
+ }
+ }
+ } else {
+ radix >>= BLIST_META_RADIX_SHIFT;
+ }
+
+ if (count > radix)
+ panic("blist_meta_fill: allocation too large");
+
+ i = (allocBlk - blk) / radix;
+ blk += i * radix;
+ i = i * next_skip + 1;
+
+ while (i <= skip && blk < allocBlk + count) {
+ daddr_t v;
+
+ v = blk + radix - allocBlk;
+ if (v > count)
+ v = count;
+
+ if (scan->bm_bighint == (daddr_t)-1)
+ panic("blst_meta_fill: filling unexpected range");
+
+ if (next_skip == 1) {
+ nblks += blst_leaf_fill(&scan[i], allocBlk, v);
+ } else {
+ nblks += blst_meta_fill(&scan[i], allocBlk, v,
+ radix, next_skip - 1, blk);
+ }
+ count -= v;
+ allocBlk += v;
+ blk += radix;
+ i += next_skip;
+ }
+ scan->u.bmu_avail -= nblks;
+ return nblks;
+}
+
+/*
* BLST_RADIX_INIT() - initialize radix tree
*
* Initialize our meta structures and bitmaps and calculate the exact
@@ -768,41 +907,41 @@
if (radix == BLIST_BMAP_RADIX) {
printf(
- "%*.*s(%04x,%d): bitmap %08x big=%d\n",
+ "%*.*s(%08llx,%lld): bitmap %08llx big=%lld\n",
tab, tab, "",
- blk, radix,
- scan->u.bmu_bitmap,
- scan->bm_bighint
+ (long long)blk, (long long)radix,
+ (long long)scan->u.bmu_bitmap,
+ (long long)scan->bm_bighint
);
return;
}
if (scan->u.bmu_avail == 0) {
printf(
- "%*.*s(%04x,%d) ALL ALLOCATED\n",
+ "%*.*s(%08llx,%lld) ALL ALLOCATED\n",
tab, tab, "",
- blk,
- radix
+ (long long)blk,
+ (long long)radix
);
return;
}
if (scan->u.bmu_avail == radix) {
printf(
- "%*.*s(%04x,%d) ALL FREE\n",
+ "%*.*s(%08llx,%lld) ALL FREE\n",
tab, tab, "",
- blk,
- radix
+ (long long)blk,
+ (long long)radix
);
return;
}
printf(
- "%*.*s(%04x,%d): subtree (%d/%d) big=%d {\n",
+ "%*.*s(%08llx,%lld): subtree (%lld/%lld) big=%lld {\n",
tab, tab, "",
- blk, radix,
- scan->u.bmu_avail,
- radix,
- scan->bm_bighint
+ (long long)blk, (long long)radix,
+ (long long)scan->u.bmu_avail,
+ (long long)radix,
+ (long long)scan->bm_bighint
);
radix >>= BLIST_META_RADIX_SHIFT;
@@ -812,9 +951,9 @@
for (i = 1; i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (daddr_t)-1) {
printf(
- "%*.*s(%04x,%d): Terminator\n",
+ "%*.*s(%08llx,%lld): Terminator\n",
tab, tab, "",
- blk, radix
+ (long long)blk, (long long)radix
);
lastState = 0;
break;
@@ -866,13 +1005,14 @@
daddr_t count = 0;
- printf("%d/%d/%d> ", bl->bl_free, size, bl->bl_radix);
+ printf("%lld/%lld/%lld> ", (long long)bl->bl_free,
+ (long long)size, (long long)bl->bl_radix);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) == NULL)
break;
switch(buf[0]) {
case 'r':
- if (sscanf(buf + 1, "%d", &count) == 1) {
+ if (sscanf(buf + 1, "%lld", &count) == 1) {
blist_resize(&bl, count, 1);
} else {
printf("?\n");
@@ -881,26 +1021,37 @@
blist_print(bl);
break;
case 'a':
- if (sscanf(buf + 1, "%d", &count) == 1) {
+ if (sscanf(buf + 1, "%lld", &count) == 1) {
daddr_t blk = blist_alloc(bl, count);
- printf(" R=%04x\n", blk);
+ printf(" R=%08llx\n", (long long)blk);
} else {
printf("?\n");
}
break;
case 'f':
- if (sscanf(buf + 1, "%x %d", &da, &count) == 2) {
+ if (sscanf(buf + 1, "%llx %lld",
+ (long long *)&da, (long long *)&count) == 2) {
blist_free(bl, da, count);
} else {
printf("?\n");
}
break;
+ case 'l':
+ if (sscanf(buf + 1, "%llx %lld",
+ (long long *)&da, (long long *)&count) == 2) {
+ printf(" n=%d\n",
+ blist_fill(bl, da, count));
+ } else {
+ printf("?\n");
+ }
+ break;
case '?':
case 'h':
puts(
"p -print\n"
"a %d -allocate\n"
"f %x %d -free\n"
+ "l %x %d -fill\n"
"r %d -resize\n"
"h/? -help"
);
Index: sys/kern/syscalls.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/syscalls.c,v
retrieving revision 1.120
diff -u -r1.120 syscalls.c
--- sys/kern/syscalls.c 2002/10/01 02:37:35 1.120
+++ sys/kern/syscalls.c 2002/10/07 13:55:51
@@ -2,8 +2,8 @@
* System call names.
*
* DO NOT EDIT-- this file is automatically generated.
- * $FreeBSD: src/sys/kern/syscalls.c,v 1.120 2002/10/01 02:37:35 rwatson Exp $
- * created from FreeBSD: src/sys/kern/syscalls.master,v 1.124 2002/10/01 02:35:59 rwatson Exp
+ * $FreeBSD$
+ * created from FreeBSD: src/sys/kern/syscalls.master,v 1.125 2002/10/02 16:48:15 archie Exp
*/
char *syscallnames[] = {
@@ -422,4 +422,5 @@
"#412", /* 412 = extattr_set_link */
"#413", /* 413 = extattr_get_link */
"#414", /* 414 = extattr_delete_link */
+ "swapoff", /* 415 = swapoff */
};
Index: sys/kern/syscalls.master
===================================================================
RCS file: /home/ncvs/src/sys/kern/syscalls.master,v
retrieving revision 1.125
diff -u -r1.125 syscalls.master
--- sys/kern/syscalls.master 2002/10/02 16:48:15 1.125
+++ sys/kern/syscalls.master 2002/10/07 13:55:52
@@ -590,3 +590,4 @@
412 UNIMPL BSD extattr_set_link
413 UNIMPL BSD extattr_get_link
414 UNIMPL BSD extattr_delete_link
+415 MSTD BSD { int swapoff(const char *name); }
Index: sys/sys/blist.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/blist.h,v
retrieving revision 1.4
diff -u -r1.4 blist.h
--- sys/sys/blist.h 2002/05/18 09:38:20 1.4
+++ sys/sys/blist.h 2002/10/07 13:55:58
@@ -9,6 +9,7 @@
* (void) blist_destroy(blist)
* blkno = blist_alloc(blist, count)
* (void) blist_free(blist, blkno, count)
+ * nblks = blist_fill(blist, blkno, count)
* (void) blist_resize(&blist, count, freeextra)
*
*
@@ -78,6 +79,7 @@
extern void blist_destroy(blist_t blist);
extern daddr_t blist_alloc(blist_t blist, daddr_t count);
extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
+extern int blist_fill(blist_t bl, daddr_t blkno, daddr_t count);
extern void blist_print(blist_t blist);
extern void blist_resize(blist_t *pblist, daddr_t count, int freenew);
Index: sys/sys/conf.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/conf.h,v
retrieving revision 1.149
diff -u -r1.149 conf.h
--- sys/sys/conf.h 2002/09/27 19:47:56 1.149
+++ sys/sys/conf.h 2002/10/07 13:55:59
@@ -267,6 +267,7 @@
};
#define SW_FREED 0x01
#define SW_SEQUENTIAL 0x02
+#define SW_CLOSING 0x04
#define sw_freed sw_flags /* XXX compat */
#ifdef _KERNEL
Index: sys/sys/syscall.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/syscall.h,v
retrieving revision 1.119
diff -u -r1.119 syscall.h
--- sys/sys/syscall.h 2002/10/01 02:37:35 1.119
+++ sys/sys/syscall.h 2002/10/07 13:56:00
@@ -2,8 +2,8 @@
* System call numbers.
*
* DO NOT EDIT-- this file is automatically generated.
- * $FreeBSD: src/sys/sys/syscall.h,v 1.119 2002/10/01 02:37:35 rwatson Exp $
- * created from FreeBSD: src/sys/kern/syscalls.master,v 1.124 2002/10/01 02:35:59 rwatson Exp
+ * $FreeBSD$
+ * created from FreeBSD: src/sys/kern/syscalls.master,v 1.125 2002/10/02 16:48:15 archie Exp
*/
#define SYS_syscall 0
@@ -317,4 +317,5 @@
#define SYS_ksem_unlink 406
#define SYS_ksem_getvalue 407
#define SYS_ksem_destroy 408
-#define SYS_MAXSYSCALL 415
+#define SYS_swapoff 415
+#define SYS_MAXSYSCALL 416
Index: sys/sys/syscall.mk
===================================================================
RCS file: /home/ncvs/src/sys/sys/syscall.mk,v
retrieving revision 1.74
diff -u -r1.74 syscall.mk
--- sys/sys/syscall.mk 2002/10/01 02:37:35 1.74
+++ sys/sys/syscall.mk 2002/10/07 13:56:00
@@ -1,7 +1,7 @@
# FreeBSD system call names.
# DO NOT EDIT-- this file is automatically generated.
-# $FreeBSD: src/sys/sys/syscall.mk,v 1.74 2002/10/01 02:37:35 rwatson Exp $
-# created from FreeBSD: src/sys/kern/syscalls.master,v 1.124 2002/10/01 02:35:59 rwatson Exp
+# $FreeBSD$
+# created from FreeBSD: src/sys/kern/syscalls.master,v 1.125 2002/10/02 16:48:15 archie Exp
MIASM = \
syscall.o \
exit.o \
@@ -265,4 +265,5 @@
ksem_open.o \
ksem_unlink.o \
ksem_getvalue.o \
- ksem_destroy.o
+ ksem_destroy.o \
+ swapoff.o
Index: sys/sys/sysproto.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/sysproto.h,v
retrieving revision 1.112
diff -u -r1.112 sysproto.h
--- sys/sys/sysproto.h 2002/10/02 16:48:16 1.112
+++ sys/sys/sysproto.h 2002/10/07 13:56:03
@@ -2,8 +2,8 @@
* System call prototypes.
*
* DO NOT EDIT-- this file is automatically generated.
- * $FreeBSD: src/sys/sys/sysproto.h,v 1.112 2002/10/02 16:48:16 archie Exp $
- * created from FreeBSD: src/sys/kern/syscalls.master,v 1.124 2002/10/01 02:35:59 rwatson Exp
+ * $FreeBSD$
+ * created from FreeBSD: src/sys/kern/syscalls.master,v 1.125 2002/10/02 16:48:15 archie Exp
*/
#ifndef _SYS_SYSPROTO_H_
@@ -1157,6 +1157,9 @@
struct ksem_destroy_args {
char id_l_[PADL_(semid_t)]; semid_t id; char id_r_[PADR_(semid_t)];
};
+struct swapoff_args {
+ char name_l_[PADL_(const char *)]; const char * name; char name_r_[PADR_(const char *)];
+};
int nosys(struct thread *, struct nosys_args *);
void sys_exit(struct thread *, struct sys_exit_args *);
int fork(struct thread *, struct fork_args *);
@@ -1419,6 +1422,7 @@
int ksem_unlink(struct thread *, struct ksem_unlink_args *);
int ksem_getvalue(struct thread *, struct ksem_getvalue_args *);
int ksem_destroy(struct thread *, struct ksem_destroy_args *);
+int swapoff(struct thread *, struct swapoff_args *);
#ifdef COMPAT_43
Index: sys/vm/swap_pager.c
===================================================================
RCS file: /home/ncvs/src/sys/vm/swap_pager.c,v
retrieving revision 1.180
diff -u -r1.180 swap_pager.c
--- sys/vm/swap_pager.c 2002/09/28 17:15:32 1.180
+++ sys/vm/swap_pager.c 2002/10/07 13:56:05
@@ -197,6 +197,7 @@
static __inline void swp_sizecheck(void);
static void swp_pager_sync_iodone(struct buf *bp);
static void swp_pager_async_iodone(struct buf *bp);
+static __inline int swp_pager_force_pagein(struct swblock *, int);
/*
* Swap bitmap functions
@@ -207,6 +208,8 @@
/*
* Metadata functions
*/
+static __inline struct swblock **
+ swp_pager_hash(vm_object_t object, vm_pindex_t index);
static void swp_pager_meta_build(vm_object_t, vm_pindex_t, daddr_t);
static void swp_pager_meta_free(vm_object_t, vm_pindex_t, daddr_t);
static void swp_pager_meta_free_all(vm_object_t);
@@ -513,12 +516,22 @@
daddr_t blk;
int npages;
{
+ struct swdevt *sp = &swdevt[BLK2DEVIDX(blk)];
+
GIANT_REQUIRED;
+ /* per-swap area stats */
+ sp->sw_used -= npages;
+
+ /*
+ * If we are attempting to stop swapping on this device, we
+ * don't want to mark any blocks free lest they be reused.
+ */
+ if (sp->sw_flags & SW_CLOSING)
+ return;
+
blist_free(swapblist, blk, npages);
vm_swap_size += npages;
- /* per-swap area stats */
- swdevt[BLK2DEVIDX(blk)].sw_used -= npages;
swp_sizecheck();
}
@@ -1623,6 +1636,147 @@
)
);
splx(s);
+}
+
+/*
+ * swap_pager_isswapped:
+ *
+ * Return 1 if at least one page in the given object is paged
+ * out to the given swap device.
+ */
+int swap_pager_isswapped(vm_object_t object, int devidx) {
+ daddr_t index = 0;
+ int bcount;
+ int i;
+
+ for (bcount = 0; bcount < object->un_pager.swp.swp_bcount; bcount++) {
+ struct swblock **pswap;
+ struct swblock *swap;
+
+ pswap = swp_pager_hash(object, index);
+
+ if ((swap = *pswap) != NULL) {
+ for (i = 0; i < SWAP_META_PAGES; ++i) {
+ daddr_t v = swap->swb_pages[i];
+ if (v != SWAPBLK_NONE &&
+ BLK2DEVIDX(v) == devidx &&
+ !vm_page_lookup(object, swap->swb_index+i))
+ return 1;
+ }
+ }
+
+ index += SWAP_META_PAGES;
+ if (index > 0x20000000)
+ panic("swap_pager_isswapped: failed to locate all swap meta blocks");
+ }
+ return 0;
+}
+
+/*
+ * swap_pager_swapoff:
+ *
+ * Page in all of the pages that have been paged out to the
+ * given device. The corresponding blocks in the bitmap must be
+ * marked as allocated and the device must be flagged SW_CLOSING.
+ * There may be no processes swapped out to the device.
+ *
+ * This routine may block.
+ */
+void
+swap_pager_swapoff(int devidx)
+{
+ struct swblock **pswap;
+ struct swblock *swap;
+ daddr_t v;
+ int i, j, k;
+ int paged;
+
+ GIANT_REQUIRED;
+
+ for (i = 0; i <= swhash_mask; i++) { /* '<=' is correct here */
+restart:
+ pswap = &swhash[i];
+ while ((swap = *pswap) != NULL) {
+ for (j = 0; j < SWAP_META_PAGES; j += paged) {
+ paged = 1;
+ v = swap->swb_pages[j];
+ if (v == SWAPBLK_NONE ||
+ BLK2DEVIDX(v) != devidx)
+ continue;
+
+ paged = swp_pager_force_pagein(swap, j);
+
+ swp_pager_freeswapspace(swap->swb_pages[j],
+ paged);
+ for (k = j; k < j + paged; k++)
+ swap->swb_pages[k] = SWAPBLK_NONE;
+ swap->swb_count -= paged;
+ if (swap->swb_count <= 0) {
+ *pswap = swap->swb_hnext;
+ --swap->swb_object->un_pager.swp.swp_bcount;
+ uma_zfree(swap_zone, swap);
+ }
+
+ goto restart;
+ }
+ pswap = &swap->swb_hnext;
+ }
+ }
+}
+
+/*
+ * SWP_PAGER_FORCE_PAGEIN() - force pages on a device to be paged in
+ *
+ * This routine dissociates the page at the given index within a
+ * swap block from its backing store, paging it in if necessary.
+ * If the page is paged in, it is placed in the inactive queue,
+ * since it had its backing store ripped out from under it. The
+ * swap metadata associated with the page is left intact. This
+ * function returns the number of pages that were dissociated
+ * from their swap backing.
+ *
+ * XXX This routine could be optimized to bring in adjacent pages
+ * on the device. (needs to be passed devidx as well)
+ */
+static __inline int
+swp_pager_force_pagein(struct swblock *swap, int idx)
+{
+ vm_object_t object;
+ vm_page_t m;
+ vm_pindex_t pindex;
+
+ object = swap->swb_object;
+ pindex = swap->swb_index + idx;
+
+ if (object->type != OBJT_SWAP)
+ panic("swp_pager_force_pagein: object not backed by swap");
+
+ m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
+ if (m->valid == VM_PAGE_BITS_ALL) {
+ /*
+ * The page is already in memory, but must be
+ * dirtied, since we're taking away its backing store.
+ */
+ vm_page_lock_queues();
+ vm_page_activate(m);
+ vm_page_dirty(m);
+ vm_page_wakeup(m);
+ vm_page_unlock_queues();
+ return 1;
+ }
+
+ vm_object_pip_add(object, 1);
+ if (swap_pager_getpages(object, &m, 1, 0) != VM_PAGER_OK)
+ panic("swap_pager_force_pagein: read from swap failed");/*XXX*/
+ vm_object_pip_subtract(object, 1);
+ vm_page_dirty(m);
+
+ vm_page_lock_queues();
+ vm_page_dontneed(m);
+ vm_page_wakeup(m);
+ vm_page_unlock_queues();
+
+ return 1;
}
/************************************************************************
Index: sys/vm/swap_pager.h
===================================================================
RCS file: /home/ncvs/src/sys/vm/swap_pager.h,v
retrieving revision 1.34
diff -u -r1.34 swap_pager.h
--- sys/vm/swap_pager.h 2002/09/05 14:04:34 1.34
+++ sys/vm/swap_pager.h 2002/10/07 13:56:05
@@ -83,9 +83,11 @@
extern int swap_pager_full;
extern struct blist *swapblist;
extern struct uma_zone *swap_zone;
+extern int nswap_lowat, nswap_hiwat;
void swap_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
boolean_t swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after);
+void swap_pager_swapoff(int devidx);
int swap_pager_swp_alloc(vm_object_t, int);
void swap_pager_copy(vm_object_t, vm_object_t, vm_pindex_t, int);
Index: sys/vm/vm_glue.c
===================================================================
RCS file: /home/ncvs/src/sys/vm/vm_glue.c,v
retrieving revision 1.157
diff -u -r1.157 vm_glue.c
--- sys/vm/vm_glue.c 2002/09/28 17:15:33 1.157
+++ sys/vm/vm_glue.c 2002/10/07 13:56:06
@@ -324,6 +324,35 @@
up = (vm_offset_t)p->p_uarea;
pmap_qenter(up, ma, UAREA_PAGES);
}
+
+/*
+ * Swap in the UAREAs of all processes swapped out to the given device.
+ */
+void
+vm_proc_swapin_all(int devidx)
+{
+ struct proc *p;
+
+retry:
+ sx_slock(&allproc_lock);
+ FOREACH_PROC_IN_SYSTEM(p) {
+ PROC_LOCK(p);
+ mtx_lock_spin(&sched_lock);
+
+ if (p->p_upages_obj != NULL &&
+ swap_pager_isswapped(p->p_upages_obj, devidx)) {
+ sx_sunlock(&allproc_lock);
+ faultin(p);
+ mtx_unlock_spin(&sched_lock);
+ PROC_UNLOCK(p);
+ goto retry;
+ }
+
+ mtx_unlock_spin(&sched_lock);
+ PROC_UNLOCK(p);
+ }
+ sx_sunlock(&allproc_lock);
+}
#endif
/*
Index: sys/vm/vm_pageout.h
===================================================================
RCS file: /home/ncvs/src/sys/vm/vm_pageout.h,v
retrieving revision 1.30
diff -u -r1.30 vm_pageout.h
--- sys/vm/vm_pageout.h 2002/03/19 22:17:45 1.30
+++ sys/vm/vm_pageout.h 2002/10/07 13:56:06
@@ -104,6 +104,12 @@
extern void vm_wait(void);
extern void vm_waitpfault(void);
+/* XXX This is probably misplaced. */
+#ifndef NO_SWAPPING
+void vm_proc_swapin_all(int);
+int swap_pager_isswapped(vm_object_t, int);
+#endif /* !NO_SWAPPING */
+
#ifdef _KERNEL
void vm_pageout_page(vm_page_t, vm_object_t);
void vm_pageout_cluster(vm_page_t, vm_object_t);
Index: sys/vm/vm_swap.c
===================================================================
RCS file: /home/ncvs/src/sys/vm/vm_swap.c,v
retrieving revision 1.122
diff -u -r1.122 vm_swap.c
--- sys/vm/vm_swap.c 2002/09/25 01:24:17 1.122
+++ sys/vm/vm_swap.c 2002/10/07 13:56:10
@@ -35,6 +35,7 @@
*/
#include "opt_swap.h"
+#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
@@ -56,6 +57,7 @@
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_param.h>
+#include <vm/vm_pageout.h>
#include <vm/swap_pager.h>
#include <vm/uma.h>
@@ -163,11 +165,12 @@
/*
* Create a special vnode op vector for swapdev_vp - we only use
- * VOP_STRATEGY(), everything else returns an error.
+ * VOP_STRATEGY() and reclaim; everything else returns an error.
*/
vop_t **swapdev_vnodeop_p;
static struct vnodeopv_entry_desc swapdev_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_defaultop },
+ { &vop_reclaim_desc, (vop_t *) vop_null },
{ &vop_strategy_desc, (vop_t *) swapdev_strategy },
{ NULL, NULL }
};
@@ -324,7 +327,7 @@
sp->sw_vp = vp;
sp->sw_dev = dev2udev(dev);
sp->sw_device = dev;
- sp->sw_flags |= SW_FREED;
+ sp->sw_flags = SW_FREED;
sp->sw_nblks = nblks;
sp->sw_used = 0;
@@ -350,7 +353,121 @@
vm_swap_size += blk;
}
+ swap_pager_full = 0;
+
return (0);
+}
+
+/*
+ * SYSCALL: swapoff(devname)
+ *
+ * Disable swapping on the given device.
+ */
+#ifndef _SYS_SYSPROTO_H_
+struct swapoff_args {
+ char *name;
+};
+#endif
+
+/*
+ * MPSAFE
+ */
+/* ARGSUSED */
+int
+swapoff(td, uap)
+ struct thread *td;
+ struct swapoff_args *uap;
+{
+ struct vnode *vp;
+ struct nameidata nd;
+ struct swdevt *sp;
+ swblk_t dvbase, vsbase;
+ u_long nblks, aligned_nblks, blk;
+ int error, index;
+
+ mtx_lock(&Giant);
+
+ error = suser(td);
+ if (error)
+ goto done;
+
+ NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, uap->name, td);
+ error = namei(&nd);
+ if (error)
+ goto done;
+ NDFREE(&nd, NDF_ONLY_PNBUF);
+ vp = nd.ni_vp;
+
+ for (sp = swdevt, index = 0 ; index < nswdev; index++, sp++) {
+ if (sp->sw_vp == vp)
+ goto found;
+ }
+ error = EINVAL;
+ goto done;
+found:
+ nblks = sp->sw_nblks;
+
+ /*
+ * We can turn off this swap device safely only if the
+ * available virtual memory in the system will fit the amount
+ * of data we will have to page back in, plus an epsilon so
+ * the system doesn't become critically low on swap space.
+ */
+ if (cnt.v_free_count + cnt.v_cache_count + vm_swap_size <
+ sp->sw_used + nswap_lowat) {
+ error = ENOMEM;
+ goto done;
+ }
+
+ /*
+ * Prevent further allocations on this device.
+ */
+ sp->sw_flags |= SW_CLOSING;
+ for (dvbase = dmmax; dvbase < nblks; dvbase += dmmax) {
+ blk = min(nblks - dvbase, dmmax);
+ vsbase = index * dmmax + dvbase * nswdev;
+ vm_swap_size -= blist_fill(swapblist, vsbase, blk);
+ }
+
+ /*
+ * Page in the contents of the device and close it.
+ */
+#ifndef NO_SWAPPING
+ vm_proc_swapin_all(index);
+#endif /* !NO_SWAPPING */
+ swap_pager_swapoff(index);
+
+ if (sp->sw_used != 0)
+ panic("swapoff: failed to locate %d swap blocks", sp->sw_used);
+
+ VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td);
+ vrele(vp);
+ sp->sw_vp = NULL;
+
+ /*
+ * Resize the bitmap based on the new largest swap device,
+ * or free the bitmap if there are no more devices.
+ */
+ for (sp = swdevt, nblks = 0; sp < swdevt + nswdev; sp++) {
+ if (sp->sw_vp == NULL)
+ continue;
+ nblks = max(nblks, sp->sw_nblks);
+ }
+
+ aligned_nblks = (nblks + (dmmax - 1)) & ~(u_long)(dmmax - 1);
+ nswap = aligned_nblks * nswdev;
+
+ if (nswap == 0) {
+ blist_destroy(swapblist);
+ swapblist = NULL;
+ vrele(swapdev_vp);
+ swapdev_vp = NULL;
+ } else
+ blist_resize(&swapblist, nswap, 0);
+
+done:
+ mtx_unlock(&Giant);
+ return (error);
}
static int
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