Added swap usage based upton the source code of `pinfo'.

1998-08-08  Martin Baulig  <martin@home-of-linux.org>

	* swap.c: Added swap usage based upton the source code
	of `pinfo'.

sysdeps/freebsd/ChangeLog

@@ -1,3 +1,8 @@
+1998-08-08  Martin Baulig  <martin@home-of-linux.org>
+
+	* swap.c: Added swap usage based upton the source code
+	of `pinfo'.
+
 1998-08-07  Martin Baulig  <martin@home-of-linux.org>
 
 	* *: Imported FreeBSD port of libgtop from Josh Sled.

sysdeps/freebsd/swap.c

@@ -23,16 +23,39 @@
 #include <glibtop/error.h>
 #include <glibtop/swap.h>
 
+#include <glibtop/xmalloc.h>
+
 #include <glibtop_suid.h>
 
+#include <sys/conf.h>
+#include <sys/rlist.h>
+
 static const unsigned long _glibtop_sysdeps_swap = 0;
 
+/* nlist structure for kernel access */
+static struct nlist nlst [] = {
+#define VM_SWAPLIST	0
+	{ "_swaplist" },/* list of free swap areas */
+#define VM_SWDEVT	1
+	{ "_swdevt" },	/* list of swap devices and sizes */
+#define VM_NSWAP	2
+	{ "_nswap" },	/* size of largest swap device */
+#define VM_NSWDEV	3
+	{ "_nswdev" },	/* number of swap devices */
+#define VM_DMMAX	4
+	{ "_dmmax" },	/* maximum size of a swap block */
+	{ 0 }
+};
+
 /* Init function. */
 
 void
 glibtop_init_swap_p (glibtop *server)
 {
 	server->sysdeps.swap = _glibtop_sysdeps_swap;
+
+	if (kvm_nlist (server->machine.kd, nlst) != 0)
+		glibtop_error_io_r (server, "kvm_nlist");
 }
 
 /* Provides information about swap usage. */
@@ -40,7 +63,140 @@ glibtop_init_swap_p (glibtop *server)
 void
 glibtop_get_swap_p (glibtop *server, glibtop_swap *buf)
 {
+	char *header;
+	int hlen, nswap, nswdev, dmmax;
+	int i, div, avail, nfree, npfree, used;
+	struct swdevt *sw;
+	long blocksize, *perdev;
+	struct rlist head;
+	struct rlisthdr swaplist;
+	struct rlist *swapptr;
+	size_t sw_size;
+	u_long ptr;
+
 	glibtop_init_p (server, GLIBTOP_SYSDEPS_SWAP, 0);
 	
 	memset (buf, 0, sizeof (glibtop_swap));
+
+	/* Size of largest swap device. */
+
+	if (kvm_read (server->machine.kd, nlst[VM_NSWAP].n_value,
+		      &nswap, sizeof (nswap)) != sizeof (nswap))
+		glibtop_error_io_r (server, "kvm_read (nswap)");
+
+	/* Number of swap devices. */
+
+	if (kvm_read (server->machine.kd, nlst[VM_NSWDEV].n_value,
+		      &nswdev, sizeof (nswdev)) != sizeof (nswdev))
+		glibtop_error_io_r (server, "kvm_read (nswdev)");
+
+	/* Maximum size of a swap block. */
+
+	if (kvm_read (server->machine.kd, nlst[VM_DMMAX].n_value,
+		      &dmmax, sizeof (dmmax)) != sizeof (dmmax))
+		glibtop_error_io_r (server, "kvm_read (dmmax)");
+
+	/* List of free swap areas. */
+
+	if (kvm_read (server->machine.kd, nlst[VM_SWAPLIST].n_value,
+		      &swaplist, sizeof (swaplist)) != sizeof (swaplist))
+		glibtop_error_io_r (server, "kvm_read (swaplist)");
+
+	/* Kernel offset of list of swap devices and sizes. */
+
+	if (kvm_read (server->machine.kd, nlst[VM_SWDEVT].n_value,
+		      &ptr, sizeof (ptr)) != sizeof (ptr))
+		glibtop_error_io_r (server, "kvm_read (swaplist)");
+
+	/* List of swap devices and sizes. */
+
+	sw_size = nswdev * sizeof (*sw);
+	sw = glibtop_malloc_r (server, sw_size);
+
+	if (kvm_read (server->machine.kd, ptr, sw, sw_size) != sw_size)
+		glibtop_error_io_r (server, "kvm_read (*swdevt)");
+
+	perdev = glibtop_malloc (nswdev * sizeof (*perdev));
+
+	/* Count up swap space. */
+
+	nfree = 0;
+	memset (perdev, 0, nswdev * sizeof(*perdev));
+
+	swapptr = swaplist.rlh_list;
+
+	while (swapptr) {
+		int	top, bottom, next_block;
+
+		if (kvm_read (server->machine.kd, swapptr, &head,
+			      sizeof (struct rlist)) != sizeof (struct rlist))
+			glibtop_error_io_r (server, "kvm_read (swapptr)");
+
+		top = head.rl_end;
+		bottom = head.rl_start;
+
+		nfree += top - bottom + 1;
+
+		/*
+		 * Swap space is split up among the configured disks.
+		 *
+		 * For interleaved swap devices, the first dmmax blocks
+		 * of swap space some from the first disk, the next dmmax
+		 * blocks from the next, and so on up to nswap blocks.
+		 *
+		 * The list of free space joins adjacent free blocks,
+		 * ignoring device boundries.  If we want to keep track
+		 * of this information per device, we'll just have to
+		 * extract it ourselves.
+		 */
+		while (top / dmmax != bottom / dmmax) {
+			next_block = ((bottom + dmmax) / dmmax);
+			perdev[(bottom / dmmax) % nswdev] +=
+				next_block * dmmax - bottom;
+			bottom = next_block * dmmax;
+		}
+		perdev[(bottom / dmmax) % nswdev] +=
+			top - bottom + 1;
+
+		swapptr = head.rl_next;
+	}
+
+	header = getbsize (&hlen, &blocksize);
+
+	div = blocksize / 512;
+	avail = npfree = 0;
+	for (i = 0; i < nswdev; i++) {
+		int xsize, xfree;
+
+		/*
+		 * Don't report statistics for partitions which have not
+		 * yet been activated via swapon(8).
+		 */
+		if (!(sw[i].sw_flags & SW_FREED))
+			continue;
+
+		/* The first dmmax is never allocated to avoid trashing of
+		 * disklabels
+		 */
+		xsize = sw[i].sw_nblks - dmmax;
+		xfree = perdev[i];
+		used = xsize - xfree;
+		npfree++;
+		avail += xsize;
+	}
+
+	/*
+	 * If only one partition has been set up via swapon(8), we don't
+	 * need to bother with totals.
+	 */
+	used = avail - nfree;
+
+	glibtop_free_r (server, sw);
+	glibtop_free_r (server, perdev);
+
+	buf->used = used;
+	buf->free = avail;
+
+	buf->total = used + avail;
+	buf->flags = _glibtop_sysdeps_swap;
 }