kvm_getswapinfo.c revision 69396 
1/*
2 * Copyright (c) 1999, Matthew Dillon.  All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided under the terms of the BSD
6 * Copyright as found in /usr/src/COPYRIGHT in the FreeBSD source tree.
7 */
8
9#ifndef lint
10static const char copyright[] =
11    "@(#) Copyright (c) 1999\n"
12    "Matthew Dillon.  All rights reserved.\n";
13#endif /* not lint */
14
15#ifndef lint
16static const char rcsid[] =
17  "$FreeBSD: head/lib/libkvm/kvm_getswapinfo.c 69396 2000-11-30 18:34:08Z alfred $";
18#endif /* not lint */
19
20#include <sys/param.h>
21#include <sys/time.h>
22#include <sys/stat.h>
23#include <sys/conf.h>
24#include <sys/blist.h>
25
26#include <err.h>
27#include <fcntl.h>
28#include <kvm.h>
29#include <nlist.h>
30#include <stdio.h>
31#include <stdlib.h>
32#include <string.h>
33#include <unistd.h>
34
35static struct nlist kvm_swap_nl[] = {
36	{ "_swapblist" },	/* new radix swap list		*/
37	{ "_swdevt" },		/* list of swap devices and sizes */
38	{ "_nswdev" },		/* number of swap devices */
39	{ "_dmmax" },		/* maximum size of a swap block */
40	{ "" }
41};
42
43#define NL_SWAPBLIST	0
44#define NL_SWDEVT	1
45#define NL_NSWDEV	2
46#define NL_DMMAX	3
47
48static int kvm_swap_nl_cached = 0;
49static int nswdev;
50static int unswdev;
51static int dmmax;
52
53static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
54			      int swap_max, int flags);
55
56#define	SVAR(var) __STRING(var)	/* to force expansion */
57#define	KGET(idx, var)							\
58	KGET1(idx, &var, sizeof(var), SVAR(var))
59#define	KGET1(idx, p, s, msg)						\
60	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
61#define	KGET2(addr, p, s, msg)						\
62	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
63		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
64#define	KGETN(idx, var)							\
65	KGET1N(idx, &var, sizeof(var), SVAR(var))
66#define	KGET1N(idx, p, s, msg)						\
67	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
68#define	KGET2N(addr, p, s, msg)						\
69	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
70#define	KGETRET(addr, p, s, msg)					\
71	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
72		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
73		return (0);						\
74	}
75
76int
77kvm_getswapinfo(
78	kvm_t *kd,
79	struct kvm_swap *swap_ary,
80	int swap_max,
81	int flags
82) {
83	int ti = 0;
84
85	/*
86	 * clear cache
87	 */
88	if (kd == NULL) {
89		kvm_swap_nl_cached = 0;
90		return(0);
91	}
92
93	/*
94	 * namelist
95	 */
96	if (kvm_swap_nl_cached == 0) {
97		struct swdevt *sw;
98
99		if (kvm_nlist(kd, kvm_swap_nl) < 0)
100			return(-1);
101
102		/*
103		 * required entries
104		 */
105
106		if (
107		    kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
108		    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
109		    kvm_swap_nl[NL_DMMAX].n_value == 0 ||
110		    kvm_swap_nl[NL_SWAPBLIST].n_type == 0
111		) {
112			return(-1);
113		}
114
115		/*
116		 * get globals, type of swap
117		 */
118
119		KGET(NL_NSWDEV, nswdev);
120		KGET(NL_DMMAX, dmmax);
121
122		/*
123		 * figure out how many actual swap devices are enabled
124		 */
125
126		KGET(NL_SWDEVT, sw);
127		for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
128			struct swdevt swinfo;
129
130			KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
131			if (swinfo.sw_nblks)
132				break;
133		}
134		++unswdev;
135
136		kvm_swap_nl_cached = 1;
137	}
138
139
140	{
141		struct swdevt *sw;
142		int i;
143
144		ti = unswdev;
145		if (ti >= swap_max)
146			ti = swap_max - 1;
147
148		if (ti >= 0)
149			bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
150
151		KGET(NL_SWDEVT, sw);
152		for (i = 0; i < unswdev; ++i) {
153			struct swdevt swinfo;
154			int ttl;
155
156			KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
157
158			/*
159			 * old style: everything in DEV_BSIZE'd chunks,
160			 * convert to pages.
161			 *
162			 * new style: swinfo in DEV_BSIZE'd chunks but dmmax
163			 * in pages.
164			 *
165			 * The first dmmax is never allocating to avoid
166			 * trashing the disklabels
167			 */
168
169			ttl = swinfo.sw_nblks - dmmax;
170
171			if (ttl == 0)
172				continue;
173
174			if (i < ti) {
175				swap_ary[i].ksw_total = ttl;
176				swap_ary[i].ksw_used = ttl;
177				swap_ary[i].ksw_flags = swinfo.sw_flags;
178				if (swinfo.sw_dev == NODEV) {
179					snprintf(
180					    swap_ary[i].ksw_devname,
181					    sizeof(swap_ary[i].ksw_devname),
182					    "%s",
183					    "[NFS swap]"
184					);
185				} else {
186					snprintf(
187					    swap_ary[i].ksw_devname,
188					    sizeof(swap_ary[i].ksw_devname),
189					    "%s%s",
190					    ((flags & SWIF_DEV_PREFIX) ? "/dev/" : ""),
191					    devname(swinfo.sw_dev, S_IFCHR)
192					);
193				}
194			}
195			if (ti >= 0) {
196				swap_ary[ti].ksw_total += ttl;
197				swap_ary[ti].ksw_used += ttl;
198			}
199		}
200	}
201
202	getswapinfo_radix(kd, swap_ary, swap_max, flags);
203	return(ti);
204}
205
206/*
207 * scanradix() - support routine for radix scanner
208 */
209
210#define TABME	tab, tab, ""
211
212static int
213scanradix(
214	blmeta_t *scan,
215	daddr_t blk,
216	daddr_t radix,
217	daddr_t skip,
218	daddr_t count,
219	kvm_t *kd,
220	int dmmax,
221	int nswdev,
222	struct kvm_swap *swap_ary,
223	int swap_max,
224	int tab,
225	int flags
226) {
227	blmeta_t meta;
228	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
229
230	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
231
232	/*
233	 * Terminator
234	 */
235	if (meta.bm_bighint == (daddr_t)-1) {
236		if (flags & SWIF_DUMP_TREE) {
237			printf("%*.*s(0x%06x,%d) Terminator\n",
238			    TABME,
239			    blk,
240			    radix
241			);
242		}
243		return(-1);
244	}
245
246	if (radix == BLIST_BMAP_RADIX) {
247		/*
248		 * Leaf bitmap
249		 */
250		int i;
251
252		if (flags & SWIF_DUMP_TREE) {
253			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
254			    TABME,
255			    blk,
256			    radix,
257			    (int)meta.u.bmu_bitmap,
258			    meta.bm_bighint
259			);
260		}
261
262		/*
263		 * If not all allocated, count.
264		 */
265		if (meta.u.bmu_bitmap != 0) {
266			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
267				/*
268				 * A 0 bit means allocated
269				 */
270				if ((meta.u.bmu_bitmap & (1 << i))) {
271					int t = 0;
272
273					if (nswdev)
274						t = (blk + i) / dmmax % nswdev;
275					if (t < ti)
276						--swap_ary[t].ksw_used;
277					if (ti >= 0)
278						--swap_ary[ti].ksw_used;
279				}
280			}
281		}
282	} else if (meta.u.bmu_avail == radix) {
283		/*
284		 * Meta node if all free
285		 */
286		if (flags & SWIF_DUMP_TREE) {
287			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
288			    TABME,
289			    blk,
290			    radix
291			);
292		}
293		/*
294		 * Note: both dmmax and radix are powers of 2.  However, dmmax
295		 * may be larger then radix so use a smaller increment if
296		 * necessary.
297		 */
298		{
299			int t;
300			int tinc = dmmax;
301
302			while (tinc > radix)
303				tinc >>= 1;
304
305			for (t = blk; t < blk + radix; t += tinc) {
306				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
307
308				if (u < ti)
309					swap_ary[u].ksw_used -= tinc;
310				if (ti >= 0)
311					swap_ary[ti].ksw_used -= tinc;
312			}
313		}
314	} else if (meta.u.bmu_avail == 0) {
315		/*
316		 * Meta node if all used
317		 */
318		if (flags & SWIF_DUMP_TREE) {
319			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
320			    TABME,
321			    blk,
322			    radix
323			);
324		}
325	} else {
326		/*
327		 * Meta node if not all free
328		 */
329		int i;
330		int next_skip;
331
332		if (flags & SWIF_DUMP_TREE) {
333			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
334			    TABME,
335			    blk,
336			    radix,
337			    (int)meta.u.bmu_avail,
338			    meta.bm_bighint
339			);
340		}
341
342		radix >>= BLIST_META_RADIX_SHIFT;
343		next_skip = skip >> BLIST_META_RADIX_SHIFT;
344
345		for (i = 1; i <= skip; i += next_skip) {
346			int r;
347			daddr_t vcount = (count > radix) ? radix : count;
348
349			r = scanradix(
350			    &scan[i],
351			    blk,
352			    radix,
353			    next_skip - 1,
354			    vcount,
355			    kd,
356			    dmmax,
357			    nswdev,
358			    swap_ary,
359			    swap_max,
360			    tab + 4,
361			    flags
362			);
363			if (r < 0)
364				break;
365			blk += radix;
366		}
367		if (flags & SWIF_DUMP_TREE) {
368			printf("%*.*s}\n", TABME);
369		}
370	}
371	return(0);
372}
373
374static void
375getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
376{
377	struct blist *swapblist = NULL;
378	struct blist blcopy = { 0 };
379
380	KGET(NL_SWAPBLIST, swapblist);
381
382	if (swapblist == NULL) {
383		if (flags & SWIF_DUMP_TREE)
384			printf("radix tree: NULL - no swap in system\n");
385		return;
386	}
387
388	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
389
390	if (flags & SWIF_DUMP_TREE) {
391		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
392			blcopy.bl_free,
393			blcopy.bl_blocks,
394			blcopy.bl_radix,
395			(int)((blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
396			    1024)
397		);
398	}
399	scanradix(
400	    blcopy.bl_root,
401	    0,
402	    blcopy.bl_radix,
403	    blcopy.bl_skip,
404	    blcopy.bl_rootblks,
405	    kd,
406	    dmmax,
407	    nswdev,
408	    swap_ary,
409	    swap_max,
410	    0,
411	    flags
412	);
413}
414