xref: /freebsd/lib/libkvm/kvm_getswapinfo.c (revision 77a0943ded95b9e6438f7db70c4a28e4d93946d4) 
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/ucred.h>
23 #include <sys/stat.h>
24 #include <sys/conf.h>
25 #include <sys/blist.h>
26 
27 #include <err.h>
28 #include <fcntl.h>
29 #include <kvm.h>
30 #include <nlist.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 static 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 
49 static int kvm_swap_nl_cached = 0;
50 static int nswdev;
51 static int unswdev;
52 static int dmmax;
53 
54 static 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 
77 int
78 kvm_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) ? "/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 
213 static int
214 scanradix(
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 
375 static void
376 getswapinfo_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