kvm_getswapinfo.c revision 69793 
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 69793 2000-12-09 09:35:55Z obrien $";
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 <paths.h>
31#include <stdio.h>
32#include <stdlib.h>
33#include <string.h>
34#include <unistd.h>
35
36static struct nlist kvm_swap_nl[] = {
37	{ "_swapblist" },	/* new radix swap list		*/
38	{ "_swdevt" },		/* list of swap devices and sizes */
39	{ "_nswdev" },		/* number of swap devices */
40	{ "_dmmax" },		/* maximum size of a swap block */
41	{ "" }
42};
43
44#define NL_SWAPBLIST	0
45#define NL_SWDEVT	1
46#define NL_NSWDEV	2
47#define NL_DMMAX	3
48
49static int kvm_swap_nl_cached = 0;
50static int nswdev;
51static int unswdev;
52static int dmmax;
53
54static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
55			      int swap_max, int flags);
56
57#define	SVAR(var) __STRING(var)	/* to force expansion */
58#define	KGET(idx, var)							\
59	KGET1(idx, &var, sizeof(var), SVAR(var))
60#define	KGET1(idx, p, s, msg)						\
61	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
62#define	KGET2(addr, p, s, msg)						\
63	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
64		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
65#define	KGETN(idx, var)							\
66	KGET1N(idx, &var, sizeof(var), SVAR(var))
67#define	KGET1N(idx, p, s, msg)						\
68	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
69#define	KGET2N(addr, p, s, msg)						\
70	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
71#define	KGETRET(addr, p, s, msg)					\
72	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
73		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
74		return (0);						\
75	}
76
77int
78kvm_getswapinfo(
79	kvm_t *kd,
80	struct kvm_swap *swap_ary,
81	int swap_max,
82	int flags
83) {
84	int ti = 0;
85
86	/*
87	 * clear cache
88	 */
89	if (kd == NULL) {
90		kvm_swap_nl_cached = 0;
91		return(0);
92	}
93
94	/*
95	 * namelist
96	 */
97	if (kvm_swap_nl_cached == 0) {
98		struct swdevt *sw;
99
100		if (kvm_nlist(kd, kvm_swap_nl) < 0)
101			return(-1);
102
103		/*
104		 * required entries
105		 */
106
107		if (
108		    kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
109		    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
110		    kvm_swap_nl[NL_DMMAX].n_value == 0 ||
111		    kvm_swap_nl[NL_SWAPBLIST].n_type == 0
112		) {
113			return(-1);
114		}
115
116		/*
117		 * get globals, type of swap
118		 */
119
120		KGET(NL_NSWDEV, nswdev);
121		KGET(NL_DMMAX, dmmax);
122
123		/*
124		 * figure out how many actual swap devices are enabled
125		 */
126
127		KGET(NL_SWDEVT, sw);
128		for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
129			struct swdevt swinfo;
130
131			KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
132			if (swinfo.sw_nblks)
133				break;
134		}
135		++unswdev;
136
137		kvm_swap_nl_cached = 1;
138	}
139
140
141	{
142		struct swdevt *sw;
143		int i;
144
145		ti = unswdev;
146		if (ti >= swap_max)
147			ti = swap_max - 1;
148
149		if (ti >= 0)
150			bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
151
152		KGET(NL_SWDEVT, sw);
153		for (i = 0; i < unswdev; ++i) {
154			struct swdevt swinfo;
155			int ttl;
156
157			KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
158
159			/*
160			 * old style: everything in DEV_BSIZE'd chunks,
161			 * convert to pages.
162			 *
163			 * new style: swinfo in DEV_BSIZE'd chunks but dmmax
164			 * in pages.
165			 *
166			 * The first dmmax is never allocating to avoid
167			 * trashing the disklabels
168			 */
169
170			ttl = swinfo.sw_nblks - dmmax;
171
172			if (ttl == 0)
173				continue;
174
175			if (i < ti) {
176				swap_ary[i].ksw_total = ttl;
177				swap_ary[i].ksw_used = ttl;
178				swap_ary[i].ksw_flags = swinfo.sw_flags;
179				if (swinfo.sw_dev == NODEV) {
180					snprintf(
181					    swap_ary[i].ksw_devname,
182					    sizeof(swap_ary[i].ksw_devname),
183					    "%s",
184					    "[NFS swap]"
185					);
186				} else {
187					snprintf(
188					    swap_ary[i].ksw_devname,
189					    sizeof(swap_ary[i].ksw_devname),
190					    "%s%s",
191					    ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),
192					    devname(swinfo.sw_dev, S_IFCHR)
193					);
194				}
195			}
196			if (ti >= 0) {
197				swap_ary[ti].ksw_total += ttl;
198				swap_ary[ti].ksw_used += ttl;
199			}
200		}
201	}
202
203	getswapinfo_radix(kd, swap_ary, swap_max, flags);
204	return(ti);
205}
206
207/*
208 * scanradix() - support routine for radix scanner
209 */
210
211#define TABME	tab, tab, ""
212
213static int
214scanradix(
215	blmeta_t *scan,
216	daddr_t blk,
217	daddr_t radix,
218	daddr_t skip,
219	daddr_t count,
220	kvm_t *kd,
221	int dmmax,
222	int nswdev,
223	struct kvm_swap *swap_ary,
224	int swap_max,
225	int tab,
226	int flags
227) {
228	blmeta_t meta;
229	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
230
231	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
232
233	/*
234	 * Terminator
235	 */
236	if (meta.bm_bighint == (daddr_t)-1) {
237		if (flags & SWIF_DUMP_TREE) {
238			printf("%*.*s(0x%06x,%d) Terminator\n",
239			    TABME,
240			    blk,
241			    radix
242			);
243		}
244		return(-1);
245	}
246
247	if (radix == BLIST_BMAP_RADIX) {
248		/*
249		 * Leaf bitmap
250		 */
251		int i;
252
253		if (flags & SWIF_DUMP_TREE) {
254			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
255			    TABME,
256			    blk,
257			    radix,
258			    (int)meta.u.bmu_bitmap,
259			    meta.bm_bighint
260			);
261		}
262
263		/*
264		 * If not all allocated, count.
265		 */
266		if (meta.u.bmu_bitmap != 0) {
267			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
268				/*
269				 * A 0 bit means allocated
270				 */
271				if ((meta.u.bmu_bitmap & (1 << i))) {
272					int t = 0;
273
274					if (nswdev)
275						t = (blk + i) / dmmax % nswdev;
276					if (t < ti)
277						--swap_ary[t].ksw_used;
278					if (ti >= 0)
279						--swap_ary[ti].ksw_used;
280				}
281			}
282		}
283	} else if (meta.u.bmu_avail == radix) {
284		/*
285		 * Meta node if all free
286		 */
287		if (flags & SWIF_DUMP_TREE) {
288			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
289			    TABME,
290			    blk,
291			    radix
292			);
293		}
294		/*
295		 * Note: both dmmax and radix are powers of 2.  However, dmmax
296		 * may be larger then radix so use a smaller increment if
297		 * necessary.
298		 */
299		{
300			int t;
301			int tinc = dmmax;
302
303			while (tinc > radix)
304				tinc >>= 1;
305
306			for (t = blk; t < blk + radix; t += tinc) {
307				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
308
309				if (u < ti)
310					swap_ary[u].ksw_used -= tinc;
311				if (ti >= 0)
312					swap_ary[ti].ksw_used -= tinc;
313			}
314		}
315	} else if (meta.u.bmu_avail == 0) {
316		/*
317		 * Meta node if all used
318		 */
319		if (flags & SWIF_DUMP_TREE) {
320			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
321			    TABME,
322			    blk,
323			    radix
324			);
325		}
326	} else {
327		/*
328		 * Meta node if not all free
329		 */
330		int i;
331		int next_skip;
332
333		if (flags & SWIF_DUMP_TREE) {
334			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
335			    TABME,
336			    blk,
337			    radix,
338			    (int)meta.u.bmu_avail,
339			    meta.bm_bighint
340			);
341		}
342
343		radix >>= BLIST_META_RADIX_SHIFT;
344		next_skip = skip >> BLIST_META_RADIX_SHIFT;
345
346		for (i = 1; i <= skip; i += next_skip) {
347			int r;
348			daddr_t vcount = (count > radix) ? radix : count;
349
350			r = scanradix(
351			    &scan[i],
352			    blk,
353			    radix,
354			    next_skip - 1,
355			    vcount,
356			    kd,
357			    dmmax,
358			    nswdev,
359			    swap_ary,
360			    swap_max,
361			    tab + 4,
362			    flags
363			);
364			if (r < 0)
365				break;
366			blk += radix;
367		}
368		if (flags & SWIF_DUMP_TREE) {
369			printf("%*.*s}\n", TABME);
370		}
371	}
372	return(0);
373}
374
375static void
376getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
377{
378	struct blist *swapblist = NULL;
379	struct blist blcopy = { 0 };
380
381	KGET(NL_SWAPBLIST, swapblist);
382
383	if (swapblist == NULL) {
384		if (flags & SWIF_DUMP_TREE)
385			printf("radix tree: NULL - no swap in system\n");
386		return;
387	}
388
389	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
390
391	if (flags & SWIF_DUMP_TREE) {
392		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
393			blcopy.bl_free,
394			blcopy.bl_blocks,
395			blcopy.bl_radix,
396			(int)((blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
397			    1024)
398		);
399	}
400	scanradix(
401	    blcopy.bl_root,
402	    0,
403	    blcopy.bl_radix,
404	    blcopy.bl_skip,
405	    blcopy.bl_rootblks,
406	    kd,
407	    dmmax,
408	    nswdev,
409	    swap_ary,
410	    swap_max,
411	    0,
412	    flags
413	);
414}
415