Implement kvm_getswapinfo() libkvm function. Will be used by

    pstat, top, and systat.

4 files changed, 551 insertions, 2 deletions

diff --git a/lib/libkvm/Makefile b/lib/libkvm/Makefile
index c31992d..0428895 100644
--- a/lib/libkvm/Makefile
+++ b/lib/libkvm/Makefile
@@ -2,10 +2,11 @@
 
 LIB=	kvm
 CFLAGS+=-DLIBC_SCCS -I${.CURDIR}/../../sys
-SRCS=	kvm.c kvm_${MACHINE_ARCH}.c kvm_file.c kvm_getloadavg.c kvm_proc.c
+SRCS=	kvm.c kvm_${MACHINE_ARCH}.c kvm_file.c kvm_getloadavg.c kvm_proc.c \
+	kvm_getswapinfo.c
 
 MAN3=	kvm.3 kvm_geterr.3 kvm_getfiles.3 kvm_getloadavg.3 kvm_getprocs.3 \
-	kvm_nlist.3 kvm_open.3 kvm_read.3
+	kvm_nlist.3 kvm_open.3 kvm_read.3 kvm_getswapinfo.3
 
 MLINKS+=kvm_getprocs.3 kvm_getargv.3 kvm_getprocs.3 kvm_getenvv.3
 MLINKS+=kvm_open.3 kvm_openfiles.3 kvm_open.3 kvm_close.3
diff --git a/lib/libkvm/kvm.3 b/lib/libkvm/kvm.3
index e0b12eb..c6f0e51 100644
--- a/lib/libkvm/kvm.3
+++ b/lib/libkvm/kvm.3
@@ -93,6 +93,7 @@ given descriptor.
 .Xr kvm_getenvv 3 ,
 .Xr kvm_geterr 3 ,
 .Xr kvm_getloadavg 3 ,
+.Xr kvm_getswapinfo 3 ,
 .Xr kvm_getprocs 3 ,
 .Xr kvm_nlist 3 ,
 .Xr kvm_open 3 ,
diff --git a/lib/libkvm/kvm_getswapinfo.3 b/lib/libkvm/kvm_getswapinfo.3
new file mode 100644
index 0000000..ea5ccaa
--- /dev/null
+++ b/lib/libkvm/kvm_getswapinfo.3
@@ -0,0 +1,61 @@
+.\" Copyright (c) 1999, Matthew Dillon.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided under the terms of the BSD
+.\" Copyright as found in /usr/src/COPYRIGHT in the FreeBSD source tree.
+.\"
+.\"
+.Dd January 22, 1999
+.Dt KVM_SWAPINFO 3
+.Os
+.Sh NAME
+.Nm kvm_swapinfo
+.Nd return swap summary statistics for the system
+.Sh SYNOPSIS
+.Fd #include <kvm.h>
+.Ft int
+.Fn kvm_swapinfo "kvm_t *kd" "struct kvm_swap *" "int maxswap" "int flags"
+.Sh DESCRIPTION
+The
+.Fn kvm_swapinfo
+function fills an array of kvm_swap structures with swap summary
+information for each swap device, for up to maxswap - 1 devices.
+The number of devices, up to maxswap - 1, is returned.  A grand
+total of all swap devices ( including any devices that go beyond
+maxswap - 1 ) is returned in one additional array entry.  This
+entry is not counted in the return value.  Thus, if you specify
+a maxswap value of 1, the function will typically return the
+value 0 and the single kvm_swap structure will be filled with
+the grand total over all swap devices.  The grand total is calculated
+from all available swap devices whether or not you made room 
+for them all in the array.
+the grant total is returned.
+.Pp
+The flags argument is currently unused and must be passed as 0.
+.Pp
+If an error occurs, -1 is returned.
+.Pp
+Each swap partition and the grand total is summarized in the kvm_swap
+structure.  This structure contains the following fields:
+.Bl -inset -width indent
+.It char ksw_devname[];
+.It int ksw_total;
+.It int ksw_used;
+.It int ksw_flags;
+.El
+.Pp
+Values are in PAGE_SIZE'd chunks ( see getpagesize() ).  ksw_flags contains
+a copy of the swap device flags.
+.PP
+.Sh CACHING
+This function caches the nlist values for various kernel variables which
+it reuses in successive calls.  You may call the function with kd == NULL 
+to clear the cache.
+.Sh DIAGNOSTICS
+If the load average was unobtainable, \-1 is returned; otherwise,
+the number of swap devices actually retrieved is returned.
+.Pp
+If the name of the swap device does not fit in the static char buffer
+in the structure, it is truncated.  The buffer is always zero terminated.
+.Sh SEE ALSO
+.Xr kvm 3
diff --git a/lib/libkvm/kvm_getswapinfo.c b/lib/libkvm/kvm_getswapinfo.c
new file mode 100644
index 0000000..54663e4
--- /dev/null
+++ b/lib/libkvm/kvm_getswapinfo.c
@@ -0,0 +1,486 @@
+/*
+ * Copyright (c) 1999, Matthew Dillon.  All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided under the terms of the BSD
+ * Copyright as found in /usr/src/COPYRIGHT in the FreeBSD source tree.
+ */
+
+#ifndef lint
+static const char copyright[] =
+    "@(#) Copyright (c) 1999\n"
+    "Matthew Dillon.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static const char rcsid[] =
+	"$Id: kvm_getswapinfo.c,v 1.38 1999/01/21 08:08:55 dillon Exp $";
+#endif /* not lint */
+
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/vnode.h>
+#include <sys/ucred.h>
+#include <sys/stat.h>
+#include <sys/conf.h>
+#include <sys/rlist.h>
+#include <sys/blist.h>
+
+#include <err.h>
+#include <fcntl.h>
+#include <kvm.h>
+#include <limits.h>
+#include <nlist.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static struct nlist kvm_swap_nl[] = {
+	{ "_swaplist" },	/* old style swap list		*/
+	{ "_swapblist" },	/* new radix swap list		*/
+	{ "_swdevt" },		/* list of swap devices and sizes */
+	{ "_nswdev" },		/* number of swap devices */
+	{ "_dmmax" },		/* maximum size of a swap block */
+	{ "" }
+};
+
+#define NL_SWAPLIST	0
+#define NL_SWAPBLIST	1
+#define NL_SWDEVT	2
+#define NL_NSWDEV	3
+#define NL_DMMAX	4
+
+static int kvm_swap_nl_cached = 0;
+static int nswdev;
+static int unswdev;
+static int dmmax;
+static int type;
+
+static void getswapinfo_old(kvm_t *kd, kvm_swap_t swap_ary, int swap_max, int flags);
+static void getswapinfo_radix(kvm_t *kd, kvm_swap_t swap_ary, int swap_max, int flags);
+
+#define	SVAR(var) __STRING(var)	/* to force expansion */
+#define	KGET(idx, var)							\
+	KGET1(idx, &var, sizeof(var), SVAR(var))
+#define	KGET1(idx, p, s, msg)						\
+	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
+#define	KGET2(addr, p, s, msg)						\
+	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
+		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
+#define	KGETN(idx, var)							\
+	KGET1N(idx, &var, sizeof(var), SVAR(var))
+#define	KGET1N(idx, p, s, msg)						\
+	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
+#define	KGET2N(addr, p, s, msg)						\
+	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
+#define	KGETRET(addr, p, s, msg)					\
+	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
+		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
+		return (0);						\
+	}
+
+int
+kvm_getswapinfo(
+	kvm_t *kd, 
+	struct kvm_swap *swap_ary,
+	int swap_max, 
+	int flags
+) {
+	int ti = 0;
+
+	/*
+	 * clear cache
+	 */
+	if (kd == NULL) {
+		kvm_swap_nl_cached = 0;
+		return(0);
+	}
+
+	/*
+	 * namelist
+	 */
+	if (kvm_swap_nl_cached == 0) {
+		struct swdevt *sw;
+
+		if (kvm_nlist(kd, kvm_swap_nl) < 0)
+			return(-1);
+
+		/*
+		 * required entries
+		 */
+
+		if (
+		    kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
+		    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
+		    kvm_swap_nl[NL_DMMAX].n_value == 0
+		) {
+			return(-1);
+		}
+
+		/*
+		 * get globals, type of swap
+		 */
+
+		KGET(NL_NSWDEV, nswdev);
+		KGET(NL_DMMAX, dmmax);
+
+		if (kvm_swap_nl[NL_SWAPLIST].n_value)
+			type = 1;
+
+		if (kvm_swap_nl[NL_SWAPBLIST].n_value)
+			type = 2;
+
+		/*
+		 * figure out how many actual swap devices are enabled
+		 */
+
+		KGET(NL_SWDEVT, sw);
+		for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
+			struct swdevt swinfo;
+
+			KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
+			if (swinfo.sw_nblks)
+				break;
+		}
+		++unswdev;
+
+		kvm_swap_nl_cached = 1;
+	}
+
+
+	{
+		struct swdevt *sw;
+		int i;
+
+		ti = unswdev;
+		if (ti >= swap_max)
+			ti = swap_max - 1;
+
+		if (ti >= 0)
+			bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
+
+		KGET(NL_SWDEVT, sw);
+		for (i = 0; i < unswdev; ++i) {
+			struct swdevt swinfo;
+			int ttl;
+
+			KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
+
+			/*
+			 * old style: everything in DEV_BSIZE'd chunks,
+			 * convert to pages.
+			 *
+			 * new style: swinfo in DEV_BSIZE'd chunks but dmmax
+			 * in pages.
+			 */
+
+			if (type == 1)
+				ttl = dbtoc(swinfo.sw_nblks);
+			else
+				ttl = swinfo.sw_nblks;
+
+			if (ttl == 0)
+				continue;
+
+			if (i < ti) {
+				swap_ary[i].ksw_total = ttl;
+				swap_ary[i].ksw_used = ttl;
+				swap_ary[i].ksw_flags = swinfo.sw_flags;
+				if (swinfo.sw_dev == NODEV) {
+					snprintf(
+					    swap_ary[i].ksw_devname,
+					    sizeof(swap_ary[i].ksw_devname),
+					    "%s",
+					    "[NFS swap]"
+					);
+				} else {
+					snprintf(
+					    swap_ary[i].ksw_devname,
+					    sizeof(swap_ary[i].ksw_devname),
+					    "%s",
+					    devname(swinfo.sw_dev, S_IFBLK)
+					);
+				}
+			}
+			if (ti >= 0) {
+				swap_ary[ti].ksw_total += ttl;
+				swap_ary[ti].ksw_used += ttl;
+			}
+		}
+	}
+
+	switch(type) {
+	case 1:
+		getswapinfo_old(kd, swap_ary, swap_max, flags);
+		break;
+	case 2:
+		getswapinfo_radix(kd, swap_ary, swap_max, flags);
+		break;
+	default:
+		ti = -1;
+		break;
+	}
+	return(ti);
+}
+
+/*
+ * scanradix() - support routine for radix scanner
+ */
+
+#define TABME	tab, tab, ""
+
+static int
+scanradix(
+	blmeta_t *scan, 
+	daddr_t blk,
+	daddr_t radix,
+	daddr_t skip, 
+	daddr_t count,
+	kvm_t *kd,
+	int dmmax, 
+	int nswdev,
+	kvm_swap_t swap_ary,
+	int swap_max,
+	int tab,
+	int flags
+) {
+	blmeta_t meta;
+	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
+
+	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
+
+	/*
+	 * Terminator
+	 */
+	if (meta.bm_bighint == (daddr_t)-1) {
+		if (flags & SWIF_DUMP_TREE) {
+			printf("%*.*s(0x%06x,%d) Terminator\n", 
+			    TABME,
+			    blk, 
+			    radix
+			);
+		}
+		return(-1);
+	}
+
+	if (radix == BLIST_BMAP_RADIX) {
+		/*
+		 * Leaf bitmap
+		 */
+		int i;
+
+		if (flags & SWIF_DUMP_TREE) {
+			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n", 
+			    TABME,
+			    blk, 
+			    radix,
+			    (int)meta.u.bmu_bitmap,
+			    meta.bm_bighint
+			);
+		}
+
+		/*
+		 * If not all allocated, count.
+		 */
+		if (meta.u.bmu_bitmap != 0) {
+			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
+				/*
+				 * A 0 bit means allocated
+				 */
+				if ((meta.u.bmu_bitmap & (1 << i))) {
+					int t = 0;
+
+					if (nswdev)
+						t = (blk + i) / dmmax % nswdev;
+					if (t < ti)
+						--swap_ary[t].ksw_used;
+					if (ti >= 0)
+						--swap_ary[ti].ksw_used;
+				}
+			}
+		}
+	} else if (meta.u.bmu_avail == radix) {
+		/*
+		 * Meta node if all free
+		 */
+		if (flags & SWIF_DUMP_TREE) {
+			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n", 
+			    TABME,
+			    blk, 
+			    radix,
+			    (int)meta.u.bmu_avail,
+			    meta.bm_bighint
+			);
+		}
+		/*
+		 * Note: both dmmax and radix are powers of 2.  However, dmmax
+		 * may be larger then radix so use a smaller increment if
+		 * necessary.
+		 */
+		{
+			int t;
+			int tinc = dmmax;
+
+			while (tinc > radix)
+				tinc >>= 1;
+
+			for (t = blk; t < blk + radix; t += tinc) {
+				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
+
+				if (u < ti)
+					swap_ary[u].ksw_used -= tinc;
+				if (ti >= 0)
+					swap_ary[ti].ksw_used -= tinc;
+			}
+		}
+	} else if (meta.u.bmu_avail == 0) {
+		/*
+		 * Meta node if all used
+		 */
+		if (flags & SWIF_DUMP_TREE) {
+			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n", 
+			    TABME,
+			    blk, 
+			    radix,
+			    (int)meta.u.bmu_avail,
+			    meta.bm_bighint
+			);
+		}
+	} else {
+		/*
+		 * Meta node if not all free
+		 */
+		int i;
+		int next_skip;
+
+		radix >>= BLIST_META_RADIX_SHIFT;
+		next_skip = skip >> BLIST_META_RADIX_SHIFT;
+
+		if (flags & SWIF_DUMP_TREE) {
+			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n", 
+			    TABME,
+			    blk, 
+			    radix,
+			    (int)meta.u.bmu_avail,
+			    meta.bm_bighint
+			);
+		}
+
+		for (i = 1; i <= skip; i += next_skip) {
+			int r;
+			daddr_t vcount = (count > radix) ? radix : count;
+
+			r = scanradix(
+			    &scan[i],
+			    blk,
+			    radix,
+			    next_skip - 1,
+			    vcount,
+			    kd,
+			    dmmax,
+			    nswdev,
+			    swap_ary,
+			    swap_max,
+			    tab + 4,
+			    flags
+			);
+			if (r < 0)
+				break;
+			blk += radix;
+		}
+		if (flags & SWIF_DUMP_TREE) {
+			printf("%*.*s}\n", TABME);
+		}
+	}
+	return(0);
+}
+
+static void
+getswapinfo_radix(kvm_t *kd, kvm_swap_t swap_ary, int swap_max, int flags)
+{
+	struct blist *swapblist = NULL;
+	struct blist blcopy = { 0 };
+
+	KGET(NL_SWAPBLIST, swapblist);
+	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
+
+	if (flags & SWIF_DUMP_TREE) {
+		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
+			blcopy.bl_free,
+			blcopy.bl_blocks,
+			blcopy.bl_radix,
+			(blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
+			    1024
+		);
+	}
+	scanradix(
+	    blcopy.bl_root, 
+	    0, 
+	    blcopy.bl_radix, 
+	    blcopy.bl_skip, 
+	    blcopy.bl_rootblks, 
+	    kd,
+	    dmmax,
+	    nswdev, 
+	    swap_ary,
+	    swap_max,
+	    0,
+	    flags
+	);
+}
+
+static void
+getswapinfo_old(kvm_t *kd, kvm_swap_t swap_ary, int swap_max, int flags)
+{
+	struct rlist *swapptr;
+	struct rlisthdr swaplist;
+	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
+
+	KGET(NL_SWAPLIST, swaplist);
+
+	swapptr = swaplist.rlh_list;
+
+	while (swapptr) {
+		int	top;
+		int	bottom;
+		int	next_block;
+		int	t;
+		int	v;
+		struct rlist head;
+
+		KGET2(swapptr, &head, sizeof(head), "swapptr");
+
+		top = head.rl_end;
+		bottom = head.rl_start;
+
+		/*
+		 * Handle interleave indexing
+		 */
+
+		while (top / dmmax != bottom / dmmax) {
+			next_block = ((bottom + dmmax) / dmmax);
+
+			t = (bottom / dmmax) % nswdev;
+			v = next_block * dmmax - bottom;
+
+			if (t < ti)
+				swap_ary[t].ksw_used -= dbtoc(v);
+			if (ti >= 0)
+				swap_ary[ti].ksw_used -= dbtoc(v);
+
+			bottom = next_block * dmmax;
+		}
+
+		t = (bottom / dmmax) % nswdev;
+		v = top - bottom + 1;
+
+		if (t < ti)
+			swap_ary[t].ksw_used -= dbtoc(v);
+		if (ti >= 0)
+			swap_ary[ti].ksw_used -= dbtoc(v);
+
+		swapptr = head.rl_next;
+	}
+}
+