xref: /freebsd/lib/libkvm/kvm_getswapinfo.c (revision 4cf49a43559ed9fdad601bdcccd2c55963008675) 
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 <limits.h>
32 #include <nlist.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37 
38 static 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 
51 static int kvm_swap_nl_cached = 0;
52 static int nswdev;
53 static int unswdev;
54 static int dmmax;
55 
56 static 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 
79 int
80 kvm_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 
215 static int
216 scanradix(
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 
381 static void
382 getswapinfo_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