kvm_getswapinfo.c revision 50476 
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 50476 1999-08-28 00:22:10Z peter $";
18#endif /* not lint */
19
20#include <sys/param.h>
21#include <sys/time.h>
22#include <sys/vnode.h>
23#include <sys/ucred.h>
24#include <sys/stat.h>
25#include <sys/conf.h>
26#include <sys/blist.h>
27
28#include <err.h>
29#include <fcntl.h>
30#include <kvm.h>
31#include <limits.h>
32#include <nlist.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36#include <unistd.h>
37
38static struct nlist kvm_swap_nl[] = {
39	{ "_swapblist" },	/* new radix swap list		*/
40	{ "_swdevt" },		/* list of swap devices and sizes */
41	{ "_nswdev" },		/* number of swap devices */
42	{ "_dmmax" },		/* maximum size of a swap block */
43	{ "" }
44};
45
46#define NL_SWAPBLIST	0
47#define NL_SWDEVT	1
48#define NL_NSWDEV	2
49#define NL_DMMAX	3
50
51static int kvm_swap_nl_cached = 0;
52static int nswdev;
53static int unswdev;
54static int dmmax;
55
56static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
57			      int swap_max, int flags);
58
59#define	SVAR(var) __STRING(var)	/* to force expansion */
60#define	KGET(idx, var)							\
61	KGET1(idx, &var, sizeof(var), SVAR(var))
62#define	KGET1(idx, p, s, msg)						\
63	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
64#define	KGET2(addr, p, s, msg)						\
65	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
66		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
67#define	KGETN(idx, var)							\
68	KGET1N(idx, &var, sizeof(var), SVAR(var))
69#define	KGET1N(idx, p, s, msg)						\
70	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
71#define	KGET2N(addr, p, s, msg)						\
72	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
73#define	KGETRET(addr, p, s, msg)					\
74	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
75		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
76		return (0);						\
77	}
78
79int
80kvm_getswapinfo(
81	kvm_t *kd,
82	struct kvm_swap *swap_ary,
83	int swap_max,
84	int flags
85) {
86	int ti = 0;
87
88	/*
89	 * clear cache
90	 */
91	if (kd == NULL) {
92		kvm_swap_nl_cached = 0;
93		return(0);
94	}
95
96	/*
97	 * namelist
98	 */
99	if (kvm_swap_nl_cached == 0) {
100		struct swdevt *sw;
101
102		if (kvm_nlist(kd, kvm_swap_nl) < 0)
103			return(-1);
104
105		/*
106		 * required entries
107		 */
108
109		if (
110		    kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
111		    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
112		    kvm_swap_nl[NL_DMMAX].n_value == 0 ||
113		    kvm_swap_nl[NL_SWAPBLIST].n_type == 0
114		) {
115			return(-1);
116		}
117
118		/*
119		 * get globals, type of swap
120		 */
121
122		KGET(NL_NSWDEV, nswdev);
123		KGET(NL_DMMAX, dmmax);
124
125		/*
126		 * figure out how many actual swap devices are enabled
127		 */
128
129		KGET(NL_SWDEVT, sw);
130		for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
131			struct swdevt swinfo;
132
133			KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
134			if (swinfo.sw_nblks)
135				break;
136		}
137		++unswdev;
138
139		kvm_swap_nl_cached = 1;
140	}
141
142
143	{
144		struct swdevt *sw;
145		int i;
146
147		ti = unswdev;
148		if (ti >= swap_max)
149			ti = swap_max - 1;
150
151		if (ti >= 0)
152			bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
153
154		KGET(NL_SWDEVT, sw);
155		for (i = 0; i < unswdev; ++i) {
156			struct swdevt swinfo;
157			int ttl;
158
159			KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
160
161			/*
162			 * old style: everything in DEV_BSIZE'd chunks,
163			 * convert to pages.
164			 *
165			 * new style: swinfo in DEV_BSIZE'd chunks but dmmax
166			 * in pages.
167			 *
168			 * The first dmmax is never allocating to avoid
169			 * trashing the disklabels
170			 */
171
172			ttl = swinfo.sw_nblks - dmmax;
173
174			if (ttl == 0)
175				continue;
176
177			if (i < ti) {
178				swap_ary[i].ksw_total = ttl;
179				swap_ary[i].ksw_used = ttl;
180				swap_ary[i].ksw_flags = swinfo.sw_flags;
181				if (swinfo.sw_dev == NODEV) {
182					snprintf(
183					    swap_ary[i].ksw_devname,
184					    sizeof(swap_ary[i].ksw_devname),
185					    "%s",
186					    "[NFS swap]"
187					);
188				} else {
189					snprintf(
190					    swap_ary[i].ksw_devname,
191					    sizeof(swap_ary[i].ksw_devname),
192					    "%s%s",
193					    ((flags & SWIF_DEV_PREFIX) ? "/dev/" : ""),
194					    devname(swinfo.sw_dev, S_IFBLK)
195					);
196				}
197			}
198			if (ti >= 0) {
199				swap_ary[ti].ksw_total += ttl;
200				swap_ary[ti].ksw_used += ttl;
201			}
202		}
203	}
204
205	getswapinfo_radix(kd, swap_ary, swap_max, flags);
206	return(ti);
207}
208
209/*
210 * scanradix() - support routine for radix scanner
211 */
212
213#define TABME	tab, tab, ""
214
215static int
216scanradix(
217	blmeta_t *scan,
218	daddr_t blk,
219	daddr_t radix,
220	daddr_t skip,
221	daddr_t count,
222	kvm_t *kd,
223	int dmmax,
224	int nswdev,
225	struct kvm_swap *swap_ary,
226	int swap_max,
227	int tab,
228	int flags
229) {
230	blmeta_t meta;
231	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
232
233	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
234
235	/*
236	 * Terminator
237	 */
238	if (meta.bm_bighint == (daddr_t)-1) {
239		if (flags & SWIF_DUMP_TREE) {
240			printf("%*.*s(0x%06x,%d) Terminator\n",
241			    TABME,
242			    blk,
243			    radix
244			);
245		}
246		return(-1);
247	}
248
249	if (radix == BLIST_BMAP_RADIX) {
250		/*
251		 * Leaf bitmap
252		 */
253		int i;
254
255		if (flags & SWIF_DUMP_TREE) {
256			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
257			    TABME,
258			    blk,
259			    radix,
260			    (int)meta.u.bmu_bitmap,
261			    meta.bm_bighint
262			);
263		}
264
265		/*
266		 * If not all allocated, count.
267		 */
268		if (meta.u.bmu_bitmap != 0) {
269			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
270				/*
271				 * A 0 bit means allocated
272				 */
273				if ((meta.u.bmu_bitmap & (1 << i))) {
274					int t = 0;
275
276					if (nswdev)
277						t = (blk + i) / dmmax % nswdev;
278					if (t < ti)
279						--swap_ary[t].ksw_used;
280					if (ti >= 0)
281						--swap_ary[ti].ksw_used;
282				}
283			}
284		}
285	} else if (meta.u.bmu_avail == radix) {
286		/*
287		 * Meta node if all free
288		 */
289		if (flags & SWIF_DUMP_TREE) {
290			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
291			    TABME,
292			    blk,
293			    radix,
294			    (int)meta.u.bmu_avail,
295			    meta.bm_bighint
296			);
297		}
298		/*
299		 * Note: both dmmax and radix are powers of 2.  However, dmmax
300		 * may be larger then radix so use a smaller increment if
301		 * necessary.
302		 */
303		{
304			int t;
305			int tinc = dmmax;
306
307			while (tinc > radix)
308				tinc >>= 1;
309
310			for (t = blk; t < blk + radix; t += tinc) {
311				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
312
313				if (u < ti)
314					swap_ary[u].ksw_used -= tinc;
315				if (ti >= 0)
316					swap_ary[ti].ksw_used -= tinc;
317			}
318		}
319	} else if (meta.u.bmu_avail == 0) {
320		/*
321		 * Meta node if all used
322		 */
323		if (flags & SWIF_DUMP_TREE) {
324			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
325			    TABME,
326			    blk,
327			    radix,
328			    (int)meta.u.bmu_avail,
329			    meta.bm_bighint
330			);
331		}
332	} else {
333		/*
334		 * Meta node if not all free
335		 */
336		int i;
337		int next_skip;
338
339		if (flags & SWIF_DUMP_TREE) {
340			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
341			    TABME,
342			    blk,
343			    radix,
344			    (int)meta.u.bmu_avail,
345			    meta.bm_bighint
346			);
347		}
348
349		radix >>= BLIST_META_RADIX_SHIFT;
350		next_skip = skip >> BLIST_META_RADIX_SHIFT;
351
352		for (i = 1; i <= skip; i += next_skip) {
353			int r;
354			daddr_t vcount = (count > radix) ? radix : count;
355
356			r = scanradix(
357			    &scan[i],
358			    blk,
359			    radix,
360			    next_skip - 1,
361			    vcount,
362			    kd,
363			    dmmax,
364			    nswdev,
365			    swap_ary,
366			    swap_max,
367			    tab + 4,
368			    flags
369			);
370			if (r < 0)
371				break;
372			blk += radix;
373		}
374		if (flags & SWIF_DUMP_TREE) {
375			printf("%*.*s}\n", TABME);
376		}
377	}
378	return(0);
379}
380
381static void
382getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
383{
384	struct blist *swapblist = NULL;
385	struct blist blcopy = { 0 };
386
387	KGET(NL_SWAPBLIST, swapblist);
388
389	if (swapblist == NULL) {
390		if (flags & SWIF_DUMP_TREE)
391			printf("radix tree: NULL - no swap in system\n");
392		return;
393	}
394
395	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
396
397	if (flags & SWIF_DUMP_TREE) {
398		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
399			blcopy.bl_free,
400			blcopy.bl_blocks,
401			blcopy.bl_radix,
402			(blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
403			    1024
404		);
405	}
406	scanradix(
407	    blcopy.bl_root,
408	    0,
409	    blcopy.bl_radix,
410	    blcopy.bl_skip,
411	    blcopy.bl_rootblks,
412	    kd,
413	    dmmax,
414	    nswdev,
415	    swap_ary,
416	    swap_max,
417	    0,
418	    flags
419	);
420}
421