xref: /dragonfly/lib/libkvm/kvm_getswapinfo.c (revision c69bf40f) 
1 /*
2  * Copyright (c) 1999 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $FreeBSD: src/lib/libkvm/kvm_getswapinfo.c,v 1.10.2.4 2003/01/12 09:23:13 dillon Exp $
35  * $DragonFly: src/lib/libkvm/kvm_getswapinfo.c,v 1.5 2006/03/18 17:15:35 dillon Exp $
36  */
37 
38 #define	_KERNEL_STRUCTURES
39 
40 #include <sys/param.h>
41 #include <sys/time.h>
42 #include <sys/ucred.h>
43 #include <sys/stat.h>
44 #include <sys/conf.h>
45 #include <sys/blist.h>
46 #include <sys/sysctl.h>
47 #include <vm/vm_param.h>
48 
49 #include <err.h>
50 #include <fcntl.h>
51 #include <kvm.h>
52 #include <nlist.h>
53 #include <paths.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 #include <limits.h>
59 
60 #include "kvm_private.h"
61 
62 static struct nlist kvm_swap_nl[] = {
63 	{ "_swapblist" },	/* new radix swap list		*/
64 	{ "_swdevt" },		/* list of swap devices and sizes */
65 	{ "_nswdev" },		/* number of swap devices */
66 	{ "_dmmax" },		/* maximum size of a swap block */
67 	{ "" }
68 };
69 
70 #define NL_SWAPBLIST	0
71 #define NL_SWDEVT	1
72 #define NL_NSWDEV	2
73 #define NL_DMMAX	3
74 
75 static int kvm_swap_nl_cached = 0;
76 static int nswdev;
77 static int unswdev;
78 static int dmmax;
79 
80 static int nlist_init(kvm_t *kd);
81 static void dump_blist(kvm_t *kd);
82 static int kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary,
83 			      int swap_max, int flags);
84 
85 #define	SVAR(var) __STRING(var)	/* to force expansion */
86 #define	KGET(idx, var)							\
87 	KGET1(idx, &var, sizeof(var), SVAR(var))
88 #define	KGET1(idx, p, s, msg)						\
89 	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
90 #define	KGET2(addr, p, s, msg)						\
91 	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
92 		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
93 #define	KGETN(idx, var)							\
94 	KGET1N(idx, &var, sizeof(var), SVAR(var))
95 #define	KGET1N(idx, p, s, msg)						\
96 	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
97 #define	KGET2N(addr, p, s, msg)						\
98 	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
99 #define	KGETRET(addr, p, s, msg)					\
100 	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
101 		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
102 		return (0);						\
103 	}
104 
105 #define GETSWDEVNAME(dev, str, flags)					\
106 	if (dev == NODEV) {						\
107 		strlcpy(str, "[NFS swap]", sizeof(str));		\
108 	} else {							\
109 		snprintf(						\
110 		    str, sizeof(str), "%s%s",				\
111 		    ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),	\
112 		    devname(dev, S_IFCHR)				\
113 		);							\
114 	}
115 
116 int
117 kvm_getswapinfo(
118 	kvm_t *kd,
119 	struct kvm_swap *swap_ary,
120 	int swap_max,
121 	int flags
122 ) {
123 	int i, ti, swi;
124 	swblk_t ttl;
125 	struct swdevt *sw;
126 	struct swdevt swinfo;
127 
128 	/*
129 	 * clear cache
130 	 */
131 	if (kd == NULL) {
132 		kvm_swap_nl_cached = 0;
133 		return(0);
134 	}
135 
136 	if (swap_max < 1)
137 		return (-1);
138 
139 	/*
140 	 * Use sysctl if possible
141 	 */
142 	if (kvm_ishost(kd) && (flags & SWIF_DUMP_TREE) == 0) {
143 		ti = kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
144 		if (ti >= 0)
145 			return(ti);
146 	}
147 
148 	/*
149 	 * namelist
150 	 */
151 	if (!nlist_init(kd))
152 		return (-1);
153 
154 	swi = unswdev;
155 	if (swi >= swap_max)
156 		swi = swap_max - 1;
157 
158 	bzero(swap_ary, sizeof(struct kvm_swap) * (swi + 1));
159 
160 	KGET(NL_SWDEVT, sw);
161 	for (i = ti = 0; i < nswdev; ++i) {
162 		KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
163 
164 		if (swinfo.sw_nblks == 0)
165 			continue;
166 
167 		/*
168 		 * The first dmmax is never allocated to avoid
169 		 * trashing the disklabels.
170 		 */
171 		ttl = swinfo.sw_nblks - dmmax;
172 		if (ttl == 0)
173 			continue;
174 
175 		swap_ary[swi].ksw_total += ttl;
176 		swap_ary[swi].ksw_used += swinfo.sw_nused;
177 
178 		if (ti < swi) {
179 			swap_ary[ti].ksw_total = ttl;
180 			swap_ary[ti].ksw_used = swinfo.sw_nused;
181 			swap_ary[ti].ksw_flags = swinfo.sw_flags;
182 			GETSWDEVNAME(swinfo.sw_dev, swap_ary[ti].ksw_devname,
183 			    flags);
184 			++ti;
185 		}
186 	}
187 
188 	if (flags & SWIF_DUMP_TREE)
189 		dump_blist(kd);
190 	return (swi);
191 }
192 
193 static int
194 nlist_init(kvm_t *kd)
195 {
196 	int i;
197 	struct swdevt *sw;
198 	struct swdevt swinfo;
199 
200 	if (kvm_swap_nl_cached)
201 		return (1);
202 
203 	if (kvm_nlist(kd, kvm_swap_nl) < 0)
204 		return (0);
205 
206 	/*
207 	 * required entries
208 	 */
209 	if (kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
210 	    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
211 	    kvm_swap_nl[NL_DMMAX].n_value == 0 ||
212 	    kvm_swap_nl[NL_SWAPBLIST].n_type == 0) {
213 		return (0);
214 	}
215 
216 	/*
217 	 * get globals, type of swap
218 	 */
219 	KGET(NL_NSWDEV, nswdev);
220 	KGET(NL_DMMAX, dmmax);
221 
222 	/*
223 	 * figure out how many actual swap devices are enabled
224 	 */
225 	KGET(NL_SWDEVT, sw);
226 	for (i = unswdev = 0; i < nswdev; ++i) {
227 		KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
228 		if (swinfo.sw_nblks)
229 			++unswdev;
230 
231 	}
232 
233 	kvm_swap_nl_cached = 1;
234 	return (1);
235 }
236 
237 /*
238  * scanradix() - support routine for radix scanner
239  */
240 
241 #define TABME	tab, tab, ""
242 
243 static int
244 scanradix(
245 	blmeta_t *scan,
246 	blmeta_t *scan_cache,
247 	swblk_t blk,
248 	int64_t radix,
249 	swblk_t skip,
250 	swblk_t count,
251 	kvm_t *kd,
252 	int dmmax,
253 	int nswdev,
254 	int64_t *availp,
255 	int tab
256 ) {
257 	blmeta_t meta;
258 	blmeta_t scan_array[BLIST_BMAP_RADIX];
259 	int i;
260 
261 	if (scan_cache) {
262 		meta = *scan_cache;
263 	} else if (skip == BLIST_META_RADIX) {
264 		if (kvm_read(kd, (u_long)scan, scan_array, sizeof(scan_array)) != sizeof(scan_array)) {
265 			warnx("cannot read %s: %s", "blmeta_t", kvm_geterr(kd));
266 			bzero(scan_array, sizeof(scan_array));
267 		}
268 		meta = scan_array[0];
269 	} else {
270 		KGET2(scan, &meta, sizeof(meta), "blmeta_t");
271 	}
272 
273 	/*
274 	 * Terminator
275 	 */
276 	if (meta.bm_bighint == (swblk_t)-1) {
277 		printf("%*.*s(0x%06jx,%jd) Terminator\n",
278 		    TABME,
279 		    (intmax_t)blk,
280 		    (intmax_t)radix
281 		);
282 		return(-1);
283 	}
284 
285 	if (radix == BLIST_BMAP_RADIX) {
286 		/*
287 		 * Leaf bitmap
288 		 */
289 		printf("%*.*s(0x%06jx,%jd) Bitmap %016jx big=%jd\n",
290 		    TABME,
291 		    (intmax_t)blk,
292 		    (intmax_t)radix,
293 		    (intmax_t)meta.u.bmu_bitmap,
294 		    (intmax_t)meta.bm_bighint
295 		);
296 
297 		if (meta.u.bmu_bitmap) {
298 			for (i = 0; i < BLIST_BMAP_RADIX; ++i) {
299 				if (meta.u.bmu_bitmap & (1 << i))
300 					++*availp;
301 			}
302 		}
303 	} else if (meta.u.bmu_avail == radix) {
304 		/*
305 		 * Meta node if all free
306 		 */
307 		printf("%*.*s(0x%06jx,%jd) Submap ALL-FREE (big=%jd) {\n",
308 		    TABME,
309 		    (intmax_t)blk,
310 		    (intmax_t)radix,
311 		    (intmax_t)meta.bm_bighint
312 		);
313 		*availp += radix;
314 	} else if (meta.u.bmu_avail == 0) {
315 		/*
316 		 * Meta node if all used
317 		 */
318 		printf("%*.*s(0x%06jx,%jd) Submap ALL-ALLOCATED (big=%jd)\n",
319 		    TABME,
320 		    (intmax_t)blk,
321 		    (intmax_t)radix,
322 		    (intmax_t)meta.bm_bighint
323 		);
324 	} else {
325 		/*
326 		 * Meta node if not all free
327 		 */
328 		int i;
329 		int next_skip;
330 		int64_t avail_tmp = 0;
331 
332 		printf("%*.*s(0x%06jx,%jd) Submap avail=%jd big=%jd {\n",
333 		    TABME,
334 		    (intmax_t)blk,
335 		    (intmax_t)radix,
336 		    (intmax_t)meta.u.bmu_avail,
337 		    (intmax_t)meta.bm_bighint
338 		);
339 
340 		radix /= BLIST_META_RADIX;
341 		next_skip = skip / BLIST_META_RADIX;
342 
343 		for (i = 1; i <= skip; i += next_skip) {
344 			int r;
345 			swblk_t vcount = (count > radix) ?
346 					(swblk_t)radix : count;
347 
348 			r = scanradix(
349 			    &scan[i],
350 			    ((next_skip == 1) ? &scan_array[i] : NULL),
351 			    blk,
352 			    radix,
353 			    next_skip - 1,
354 			    vcount,
355 			    kd,
356 			    dmmax,
357 			    nswdev,
358 			    &avail_tmp,
359 			    tab + 4
360 			);
361 			if (r < 0)
362 				break;
363 			blk += (swblk_t)radix;
364 		}
365 		*availp += avail_tmp;
366 		if (avail_tmp == meta.u.bmu_avail)
367 			printf("%*.*s}\n", TABME);
368 		else
369 			printf("%*.*s} (AVAIL MISMATCH %jd/%jd\n",
370 				TABME,
371 				(intmax_t)avail_tmp,
372 				(intmax_t)meta.u.bmu_avail);
373 	}
374 	return(0);
375 }
376 
377 static void
378 dump_blist(kvm_t *kd)
379 {
380 	struct blist *swapblist = NULL;
381 	struct blist blcopy = { 0 };
382 	int64_t avail = 0;
383 
384 	KGET(NL_SWAPBLIST, swapblist);
385 
386 	if (swapblist == NULL) {
387 		printf("radix tree: NULL - no swap in system\n");
388 		return;
389 	}
390 
391 	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
392 
393 	printf("radix tree: %jd/%jd/%jd blocks, %jdK wired\n",
394 		(intmax_t)blcopy.bl_free,
395 		(intmax_t)blcopy.bl_blocks,
396 		(intmax_t)blcopy.bl_radix,
397 		(intmax_t)((blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
398 		    1024)
399 	);
400 
401 	scanradix(
402 	    blcopy.bl_root,
403 	    NULL,
404 	    0,
405 	    blcopy.bl_radix,
406 	    blcopy.bl_skip,
407 	    blcopy.bl_rootblks,
408 	    kd,
409 	    dmmax,
410 	    nswdev,
411 	    &avail,
412 	    0
413 	);
414 	printf("final availability: %jd\n", (intmax_t)avail);
415 }
416 
417 static
418 int
419 kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary,
420 		       int swap_max, int flags)
421 {
422 	size_t bytes = 0;
423 	size_t ksize;
424 	int ti;
425 	int swi;
426 	int n;
427 	int i;
428 	char *xswbuf;
429 	struct xswdev *xsw;
430 
431 	if (sysctlbyname("vm.swap_info_array", NULL, &bytes, NULL, 0) < 0)
432 		return(-1);
433 	if (bytes == 0)
434 		return(-1);
435 
436 	xswbuf = malloc(bytes);
437 	if (sysctlbyname("vm.swap_info_array", xswbuf, &bytes, NULL, 0) < 0) {
438 		free(xswbuf);
439 		return(-1);
440 	}
441 	if (bytes == 0) {
442 		free(xswbuf);
443 		return(-1);
444 	}
445 
446 	/*
447 	 * Calculate size of xsw entry returned by kernel (it can be larger
448 	 * than the one we have if there is a version mismatch).
449 	 */
450 	ksize = ((struct xswdev *)xswbuf)->xsw_size;
451 	n = (int)(bytes / ksize);
452 
453 	/*
454 	 * Calculate the number of live swap devices and calculate
455 	 * the swap_ary[] index used for the cumulative result (swi)
456 	 */
457 	for (i = swi = 0; i < n; ++i) {
458 		xsw = (void *)((char *)xswbuf + i * ksize);
459 		if ((xsw->xsw_flags & SW_FREED) == 0)
460 			continue;
461 		++swi;
462 	}
463 	if (swi >= swap_max)
464 		swi = swap_max - 1;
465 
466 	bzero(swap_ary, sizeof(struct kvm_swap) * (swi + 1));
467 
468 	/*
469 	 * Accumulate results.  If the provided swap_ary[] is too
470 	 * small will only populate up to the available entries,
471 	 * but we always populate the cumulative results entry.
472 	 */
473 	for (i = ti = 0; i < n; ++i) {
474 		xsw = (void *)((char *)xswbuf + i * ksize);
475 
476 		if ((xsw->xsw_flags & SW_FREED) == 0)
477 			continue;
478 
479 		swap_ary[swi].ksw_total += xsw->xsw_nblks;
480 		swap_ary[swi].ksw_used += xsw->xsw_used;
481 
482 		if (ti < swi) {
483 			swap_ary[ti].ksw_total = xsw->xsw_nblks;
484 			swap_ary[ti].ksw_used = xsw->xsw_used;
485 			swap_ary[ti].ksw_flags = xsw->xsw_flags;
486 			GETSWDEVNAME(xsw->xsw_dev, swap_ary[ti].ksw_devname,
487 			    flags);
488 			++ti;
489 		}
490 	}
491 
492 	free(xswbuf);
493 	return(swi);
494 }
495