xref: /freebsd/lib/libkvm/kvm_getswapinfo.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e) 
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
10 static const char copyright[] =
11     "@(#) Copyright (c) 1999\n"
12     "Matthew Dillon.  All rights reserved.\n";
13 #endif /* not lint */
14 
15 #ifndef lint
16 static const char rcsid[] =
17   "$FreeBSD$";
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 
37 static 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 
50 static int kvm_swap_nl_cached = 0;
51 static int nswdev;
52 static int unswdev;
53 static int dmmax;
54 
55 static 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 
78 int
79 kvm_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 
214 static int
215 scanradix(
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 			    (int)meta.u.bmu_avail,
294 			    meta.bm_bighint
295 			);
296 		}
297 		/*
298 		 * Note: both dmmax and radix are powers of 2.  However, dmmax
299 		 * may be larger then radix so use a smaller increment if
300 		 * necessary.
301 		 */
302 		{
303 			int t;
304 			int tinc = dmmax;
305 
306 			while (tinc > radix)
307 				tinc >>= 1;
308 
309 			for (t = blk; t < blk + radix; t += tinc) {
310 				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
311 
312 				if (u < ti)
313 					swap_ary[u].ksw_used -= tinc;
314 				if (ti >= 0)
315 					swap_ary[ti].ksw_used -= tinc;
316 			}
317 		}
318 	} else if (meta.u.bmu_avail == 0) {
319 		/*
320 		 * Meta node if all used
321 		 */
322 		if (flags & SWIF_DUMP_TREE) {
323 			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
324 			    TABME,
325 			    blk,
326 			    radix,
327 			    (int)meta.u.bmu_avail,
328 			    meta.bm_bighint
329 			);
330 		}
331 	} else {
332 		/*
333 		 * Meta node if not all free
334 		 */
335 		int i;
336 		int next_skip;
337 
338 		if (flags & SWIF_DUMP_TREE) {
339 			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
340 			    TABME,
341 			    blk,
342 			    radix,
343 			    (int)meta.u.bmu_avail,
344 			    meta.bm_bighint
345 			);
346 		}
347 
348 		radix >>= BLIST_META_RADIX_SHIFT;
349 		next_skip = skip >> BLIST_META_RADIX_SHIFT;
350 
351 		for (i = 1; i <= skip; i += next_skip) {
352 			int r;
353 			daddr_t vcount = (count > radix) ? radix : count;
354 
355 			r = scanradix(
356 			    &scan[i],
357 			    blk,
358 			    radix,
359 			    next_skip - 1,
360 			    vcount,
361 			    kd,
362 			    dmmax,
363 			    nswdev,
364 			    swap_ary,
365 			    swap_max,
366 			    tab + 4,
367 			    flags
368 			);
369 			if (r < 0)
370 				break;
371 			blk += radix;
372 		}
373 		if (flags & SWIF_DUMP_TREE) {
374 			printf("%*.*s}\n", TABME);
375 		}
376 	}
377 	return(0);
378 }
379 
380 static void
381 getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
382 {
383 	struct blist *swapblist = NULL;
384 	struct blist blcopy = { 0 };
385 
386 	KGET(NL_SWAPBLIST, swapblist);
387 
388 	if (swapblist == NULL) {
389 		if (flags & SWIF_DUMP_TREE)
390 			printf("radix tree: NULL - no swap in system\n");
391 		return;
392 	}
393 
394 	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
395 
396 	if (flags & SWIF_DUMP_TREE) {
397 		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
398 			blcopy.bl_free,
399 			blcopy.bl_blocks,
400 			blcopy.bl_radix,
401 			(blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
402 			    1024
403 		);
404 	}
405 	scanradix(
406 	    blcopy.bl_root,
407 	    0,
408 	    blcopy.bl_radix,
409 	    blcopy.bl_skip,
410 	    blcopy.bl_rootblks,
411 	    kd,
412 	    dmmax,
413 	    nswdev,
414 	    swap_ary,
415 	    swap_max,
416 	    0,
417 	    flags
418 	);
419 }
420