kvm_getswapinfo.c revision 58642 
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 58642 2000-03-27 00:33:45Z obrien $";
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 <nlist.h>
32#include <stdio.h>
33#include <stdlib.h>
34#include <string.h>
35#include <unistd.h>
36
37static struct nlist kvm_swap_nl[] = {
38	{ "_swapblist" },	/* new radix swap list		*/
39	{ "_swdevt" },		/* list of swap devices and sizes */
40	{ "_nswdev" },		/* number of swap devices */
41	{ "_dmmax" },		/* maximum size of a swap block */
42	{ "" }
43};
44
45#define NL_SWAPBLIST	0
46#define NL_SWDEVT	1
47#define NL_NSWDEV	2
48#define NL_DMMAX	3
49
50static int kvm_swap_nl_cached = 0;
51static int nswdev;
52static int unswdev;
53static int dmmax;
54
55static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
56			      int swap_max, int flags);
57
58#define	SVAR(var) __STRING(var)	/* to force expansion */
59#define	KGET(idx, var)							\
60	KGET1(idx, &var, sizeof(var), SVAR(var))
61#define	KGET1(idx, p, s, msg)						\
62	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
63#define	KGET2(addr, p, s, msg)						\
64	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
65		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
66#define	KGETN(idx, var)							\
67	KGET1N(idx, &var, sizeof(var), SVAR(var))
68#define	KGET1N(idx, p, s, msg)						\
69	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
70#define	KGET2N(addr, p, s, msg)						\
71	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
72#define	KGETRET(addr, p, s, msg)					\
73	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
74		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
75		return (0);						\
76	}
77
78int
79kvm_getswapinfo(
80	kvm_t *kd,
81	struct kvm_swap *swap_ary,
82	int swap_max,
83	int flags
84) {
85	int ti = 0;
86
87	/*
88	 * clear cache
89	 */
90	if (kd == NULL) {
91		kvm_swap_nl_cached = 0;
92		return(0);
93	}
94
95	/*
96	 * namelist
97	 */
98	if (kvm_swap_nl_cached == 0) {
99		struct swdevt *sw;
100
101		if (kvm_nlist(kd, kvm_swap_nl) < 0)
102			return(-1);
103
104		/*
105		 * required entries
106		 */
107
108		if (
109		    kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
110		    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
111		    kvm_swap_nl[NL_DMMAX].n_value == 0 ||
112		    kvm_swap_nl[NL_SWAPBLIST].n_type == 0
113		) {
114			return(-1);
115		}
116
117		/*
118		 * get globals, type of swap
119		 */
120
121		KGET(NL_NSWDEV, nswdev);
122		KGET(NL_DMMAX, dmmax);
123
124		/*
125		 * figure out how many actual swap devices are enabled
126		 */
127
128		KGET(NL_SWDEVT, sw);
129		for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
130			struct swdevt swinfo;
131
132			KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
133			if (swinfo.sw_nblks)
134				break;
135		}
136		++unswdev;
137
138		kvm_swap_nl_cached = 1;
139	}
140
141
142	{
143		struct swdevt *sw;
144		int i;
145
146		ti = unswdev;
147		if (ti >= swap_max)
148			ti = swap_max - 1;
149
150		if (ti >= 0)
151			bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
152
153		KGET(NL_SWDEVT, sw);
154		for (i = 0; i < unswdev; ++i) {
155			struct swdevt swinfo;
156			int ttl;
157
158			KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
159
160			/*
161			 * old style: everything in DEV_BSIZE'd chunks,
162			 * convert to pages.
163			 *
164			 * new style: swinfo in DEV_BSIZE'd chunks but dmmax
165			 * in pages.
166			 *
167			 * The first dmmax is never allocating to avoid
168			 * trashing the disklabels
169			 */
170
171			ttl = swinfo.sw_nblks - dmmax;
172
173			if (ttl == 0)
174				continue;
175
176			if (i < ti) {
177				swap_ary[i].ksw_total = ttl;
178				swap_ary[i].ksw_used = ttl;
179				swap_ary[i].ksw_flags = swinfo.sw_flags;
180				if (swinfo.sw_dev == NODEV) {
181					snprintf(
182					    swap_ary[i].ksw_devname,
183					    sizeof(swap_ary[i].ksw_devname),
184					    "%s",
185					    "[NFS swap]"
186					);
187				} else {
188					snprintf(
189					    swap_ary[i].ksw_devname,
190					    sizeof(swap_ary[i].ksw_devname),
191					    "%s%s",
192					    ((flags & SWIF_DEV_PREFIX) ? "/dev/" : ""),
193					    devname(swinfo.sw_dev, S_IFCHR)
194					);
195				}
196			}
197			if (ti >= 0) {
198				swap_ary[ti].ksw_total += ttl;
199				swap_ary[ti].ksw_used += ttl;
200			}
201		}
202	}
203
204	getswapinfo_radix(kd, swap_ary, swap_max, flags);
205	return(ti);
206}
207
208/*
209 * scanradix() - support routine for radix scanner
210 */
211
212#define TABME	tab, tab, ""
213
214static int
215scanradix(
216	blmeta_t *scan,
217	daddr_t blk,
218	daddr_t radix,
219	daddr_t skip,
220	daddr_t count,
221	kvm_t *kd,
222	int dmmax,
223	int nswdev,
224	struct kvm_swap *swap_ary,
225	int swap_max,
226	int tab,
227	int flags
228) {
229	blmeta_t meta;
230	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
231
232	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
233
234	/*
235	 * Terminator
236	 */
237	if (meta.bm_bighint == (daddr_t)-1) {
238		if (flags & SWIF_DUMP_TREE) {
239			printf("%*.*s(0x%06x,%d) Terminator\n",
240			    TABME,
241			    blk,
242			    radix
243			);
244		}
245		return(-1);
246	}
247
248	if (radix == BLIST_BMAP_RADIX) {
249		/*
250		 * Leaf bitmap
251		 */
252		int i;
253
254		if (flags & SWIF_DUMP_TREE) {
255			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
256			    TABME,
257			    blk,
258			    radix,
259			    (int)meta.u.bmu_bitmap,
260			    meta.bm_bighint
261			);
262		}
263
264		/*
265		 * If not all allocated, count.
266		 */
267		if (meta.u.bmu_bitmap != 0) {
268			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
269				/*
270				 * A 0 bit means allocated
271				 */
272				if ((meta.u.bmu_bitmap & (1 << i))) {
273					int t = 0;
274
275					if (nswdev)
276						t = (blk + i) / dmmax % nswdev;
277					if (t < ti)
278						--swap_ary[t].ksw_used;
279					if (ti >= 0)
280						--swap_ary[ti].ksw_used;
281				}
282			}
283		}
284	} else if (meta.u.bmu_avail == radix) {
285		/*
286		 * Meta node if all free
287		 */
288		if (flags & SWIF_DUMP_TREE) {
289			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
290			    TABME,
291			    blk,
292			    radix
293			);
294		}
295		/*
296		 * Note: both dmmax and radix are powers of 2.  However, dmmax
297		 * may be larger then radix so use a smaller increment if
298		 * necessary.
299		 */
300		{
301			int t;
302			int tinc = dmmax;
303
304			while (tinc > radix)
305				tinc >>= 1;
306
307			for (t = blk; t < blk + radix; t += tinc) {
308				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
309
310				if (u < ti)
311					swap_ary[u].ksw_used -= tinc;
312				if (ti >= 0)
313					swap_ary[ti].ksw_used -= tinc;
314			}
315		}
316	} else if (meta.u.bmu_avail == 0) {
317		/*
318		 * Meta node if all used
319		 */
320		if (flags & SWIF_DUMP_TREE) {
321			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
322			    TABME,
323			    blk,
324			    radix
325			);
326		}
327	} else {
328		/*
329		 * Meta node if not all free
330		 */
331		int i;
332		int next_skip;
333
334		if (flags & SWIF_DUMP_TREE) {
335			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
336			    TABME,
337			    blk,
338			    radix,
339			    (int)meta.u.bmu_avail,
340			    meta.bm_bighint
341			);
342		}
343
344		radix >>= BLIST_META_RADIX_SHIFT;
345		next_skip = skip >> BLIST_META_RADIX_SHIFT;
346
347		for (i = 1; i <= skip; i += next_skip) {
348			int r;
349			daddr_t vcount = (count > radix) ? radix : count;
350
351			r = scanradix(
352			    &scan[i],
353			    blk,
354			    radix,
355			    next_skip - 1,
356			    vcount,
357			    kd,
358			    dmmax,
359			    nswdev,
360			    swap_ary,
361			    swap_max,
362			    tab + 4,
363			    flags
364			);
365			if (r < 0)
366				break;
367			blk += radix;
368		}
369		if (flags & SWIF_DUMP_TREE) {
370			printf("%*.*s}\n", TABME);
371		}
372	}
373	return(0);
374}
375
376static void
377getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
378{
379	struct blist *swapblist = NULL;
380	struct blist blcopy = { 0 };
381
382	KGET(NL_SWAPBLIST, swapblist);
383
384	if (swapblist == NULL) {
385		if (flags & SWIF_DUMP_TREE)
386			printf("radix tree: NULL - no swap in system\n");
387		return;
388	}
389
390	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
391
392	if (flags & SWIF_DUMP_TREE) {
393		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
394			blcopy.bl_free,
395			blcopy.bl_blocks,
396			blcopy.bl_radix,
397			(int)((blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
398			    1024)
399		);
400	}
401	scanradix(
402	    blcopy.bl_root,
403	    0,
404	    blcopy.bl_radix,
405	    blcopy.bl_skip,
406	    blcopy.bl_rootblks,
407	    kd,
408	    dmmax,
409	    nswdev,
410	    swap_ary,
411	    swap_max,
412	    0,
413	    flags
414	);
415}
416