kvm_getswapinfo.c revision 43282 
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	"$Id: kvm_getswapinfo.c,v 1.3 1999/01/25 04:07:07 dillon Exp $";
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/rlist.h>
27#include <sys/blist.h>
28
29#include <err.h>
30#include <fcntl.h>
31#include <kvm.h>
32#include <limits.h>
33#include <nlist.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38
39static struct nlist kvm_swap_nl[] = {
40	{ "_swaplist" },	/* old style swap list		*/
41	{ "_swapblist" },	/* new radix swap list		*/
42	{ "_swdevt" },		/* list of swap devices and sizes */
43	{ "_nswdev" },		/* number of swap devices */
44	{ "_dmmax" },		/* maximum size of a swap block */
45	{ "" }
46};
47
48#define NL_SWAPLIST	0
49#define NL_SWAPBLIST	1
50#define NL_SWDEVT	2
51#define NL_NSWDEV	3
52#define NL_DMMAX	4
53
54static int kvm_swap_nl_cached = 0;
55static int nswdev;
56static int unswdev;
57static int dmmax;
58static int type;
59
60static void getswapinfo_old(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
61			    int flags);
62static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
63			      int swap_max, int flags);
64
65#define	SVAR(var) __STRING(var)	/* to force expansion */
66#define	KGET(idx, var)							\
67	KGET1(idx, &var, sizeof(var), SVAR(var))
68#define	KGET1(idx, p, s, msg)						\
69	KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
70#define	KGET2(addr, p, s, msg)						\
71	if (kvm_read(kd, (u_long)(addr), p, s) != s)			\
72		warnx("cannot read %s: %s", msg, kvm_geterr(kd))
73#define	KGETN(idx, var)							\
74	KGET1N(idx, &var, sizeof(var), SVAR(var))
75#define	KGET1N(idx, p, s, msg)						\
76	KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
77#define	KGET2N(addr, p, s, msg)						\
78	((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
79#define	KGETRET(addr, p, s, msg)					\
80	if (kvm_read(kd, (u_long)(addr), p, s) != s) {			\
81		warnx("cannot read %s: %s", msg, kvm_geterr(kd));	\
82		return (0);						\
83	}
84
85int
86kvm_getswapinfo(
87	kvm_t *kd,
88	struct kvm_swap *swap_ary,
89	int swap_max,
90	int flags
91) {
92	int ti = 0;
93
94	/*
95	 * clear cache
96	 */
97	if (kd == NULL) {
98		kvm_swap_nl_cached = 0;
99		return(0);
100	}
101
102	/*
103	 * namelist
104	 */
105	if (kvm_swap_nl_cached == 0) {
106		struct swdevt *sw;
107
108		if (kvm_nlist(kd, kvm_swap_nl) < 0)
109			return(-1);
110
111		/*
112		 * required entries
113		 */
114
115		if (
116		    kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
117		    kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
118		    kvm_swap_nl[NL_DMMAX].n_value == 0
119		) {
120			return(-1);
121		}
122
123		/*
124		 * get globals, type of swap
125		 */
126
127		KGET(NL_NSWDEV, nswdev);
128		KGET(NL_DMMAX, dmmax);
129
130		if (kvm_swap_nl[NL_SWAPLIST].n_value)
131			type = 1;
132
133		if (kvm_swap_nl[NL_SWAPBLIST].n_value)
134			type = 2;
135
136		/*
137		 * figure out how many actual swap devices are enabled
138		 */
139
140		KGET(NL_SWDEVT, sw);
141		for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
142			struct swdevt swinfo;
143
144			KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
145			if (swinfo.sw_nblks)
146				break;
147		}
148		++unswdev;
149
150		kvm_swap_nl_cached = 1;
151	}
152
153
154	{
155		struct swdevt *sw;
156		int i;
157
158		ti = unswdev;
159		if (ti >= swap_max)
160			ti = swap_max - 1;
161
162		if (ti >= 0)
163			bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
164
165		KGET(NL_SWDEVT, sw);
166		for (i = 0; i < unswdev; ++i) {
167			struct swdevt swinfo;
168			int ttl;
169
170			KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
171
172			/*
173			 * old style: everything in DEV_BSIZE'd chunks,
174			 * convert to pages.
175			 *
176			 * new style: swinfo in DEV_BSIZE'd chunks but dmmax
177			 * in pages.
178			 */
179
180			if (type == 1)
181				ttl = dbtoc(swinfo.sw_nblks);
182			else
183				ttl = swinfo.sw_nblks;
184
185			if (ttl == 0)
186				continue;
187
188			if (i < ti) {
189				swap_ary[i].ksw_total = ttl;
190				swap_ary[i].ksw_used = ttl;
191				swap_ary[i].ksw_flags = swinfo.sw_flags;
192				if (swinfo.sw_dev == NODEV) {
193					snprintf(
194					    swap_ary[i].ksw_devname,
195					    sizeof(swap_ary[i].ksw_devname),
196					    "%s",
197					    "[NFS swap]"
198					);
199				} else {
200					snprintf(
201					    swap_ary[i].ksw_devname,
202					    sizeof(swap_ary[i].ksw_devname),
203					    "%s%s",
204					    ((flags & SWIF_DEV_PREFIX) ? "/dev/" : ""),
205					    devname(swinfo.sw_dev, S_IFBLK)
206					);
207				}
208			}
209			if (ti >= 0) {
210				swap_ary[ti].ksw_total += ttl;
211				swap_ary[ti].ksw_used += ttl;
212			}
213		}
214	}
215
216	switch(type) {
217	case 1:
218		getswapinfo_old(kd, swap_ary, swap_max, flags);
219		break;
220	case 2:
221		getswapinfo_radix(kd, swap_ary, swap_max, flags);
222		break;
223	default:
224		ti = -1;
225		break;
226	}
227	return(ti);
228}
229
230/*
231 * scanradix() - support routine for radix scanner
232 */
233
234#define TABME	tab, tab, ""
235
236static int
237scanradix(
238	blmeta_t *scan,
239	daddr_t blk,
240	daddr_t radix,
241	daddr_t skip,
242	daddr_t count,
243	kvm_t *kd,
244	int dmmax,
245	int nswdev,
246	struct kvm_swap *swap_ary,
247	int swap_max,
248	int tab,
249	int flags
250) {
251	blmeta_t meta;
252	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
253
254	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
255
256	/*
257	 * Terminator
258	 */
259	if (meta.bm_bighint == (daddr_t)-1) {
260		if (flags & SWIF_DUMP_TREE) {
261			printf("%*.*s(0x%06x,%d) Terminator\n",
262			    TABME,
263			    blk,
264			    radix
265			);
266		}
267		return(-1);
268	}
269
270	if (radix == BLIST_BMAP_RADIX) {
271		/*
272		 * Leaf bitmap
273		 */
274		int i;
275
276		if (flags & SWIF_DUMP_TREE) {
277			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
278			    TABME,
279			    blk,
280			    radix,
281			    (int)meta.u.bmu_bitmap,
282			    meta.bm_bighint
283			);
284		}
285
286		/*
287		 * If not all allocated, count.
288		 */
289		if (meta.u.bmu_bitmap != 0) {
290			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
291				/*
292				 * A 0 bit means allocated
293				 */
294				if ((meta.u.bmu_bitmap & (1 << i))) {
295					int t = 0;
296
297					if (nswdev)
298						t = (blk + i) / dmmax % nswdev;
299					if (t < ti)
300						--swap_ary[t].ksw_used;
301					if (ti >= 0)
302						--swap_ary[ti].ksw_used;
303				}
304			}
305		}
306	} else if (meta.u.bmu_avail == radix) {
307		/*
308		 * Meta node if all free
309		 */
310		if (flags & SWIF_DUMP_TREE) {
311			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
312			    TABME,
313			    blk,
314			    radix,
315			    (int)meta.u.bmu_avail,
316			    meta.bm_bighint
317			);
318		}
319		/*
320		 * Note: both dmmax and radix are powers of 2.  However, dmmax
321		 * may be larger then radix so use a smaller increment if
322		 * necessary.
323		 */
324		{
325			int t;
326			int tinc = dmmax;
327
328			while (tinc > radix)
329				tinc >>= 1;
330
331			for (t = blk; t < blk + radix; t += tinc) {
332				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
333
334				if (u < ti)
335					swap_ary[u].ksw_used -= tinc;
336				if (ti >= 0)
337					swap_ary[ti].ksw_used -= tinc;
338			}
339		}
340	} else if (meta.u.bmu_avail == 0) {
341		/*
342		 * Meta node if all used
343		 */
344		if (flags & SWIF_DUMP_TREE) {
345			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
346			    TABME,
347			    blk,
348			    radix,
349			    (int)meta.u.bmu_avail,
350			    meta.bm_bighint
351			);
352		}
353	} else {
354		/*
355		 * Meta node if not all free
356		 */
357		int i;
358		int next_skip;
359
360		if (flags & SWIF_DUMP_TREE) {
361			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
362			    TABME,
363			    blk,
364			    radix,
365			    (int)meta.u.bmu_avail,
366			    meta.bm_bighint
367			);
368		}
369
370		radix >>= BLIST_META_RADIX_SHIFT;
371		next_skip = skip >> BLIST_META_RADIX_SHIFT;
372
373		for (i = 1; i <= skip; i += next_skip) {
374			int r;
375			daddr_t vcount = (count > radix) ? radix : count;
376
377			r = scanradix(
378			    &scan[i],
379			    blk,
380			    radix,
381			    next_skip - 1,
382			    vcount,
383			    kd,
384			    dmmax,
385			    nswdev,
386			    swap_ary,
387			    swap_max,
388			    tab + 4,
389			    flags
390			);
391			if (r < 0)
392				break;
393			blk += radix;
394		}
395		if (flags & SWIF_DUMP_TREE) {
396			printf("%*.*s}\n", TABME);
397		}
398	}
399	return(0);
400}
401
402static void
403getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
404{
405	struct blist *swapblist = NULL;
406	struct blist blcopy = { 0 };
407
408	KGET(NL_SWAPBLIST, swapblist);
409	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
410
411	if (flags & SWIF_DUMP_TREE) {
412		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
413			blcopy.bl_free,
414			blcopy.bl_blocks,
415			blcopy.bl_radix,
416			(blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
417			    1024
418		);
419	}
420	scanradix(
421	    blcopy.bl_root,
422	    0,
423	    blcopy.bl_radix,
424	    blcopy.bl_skip,
425	    blcopy.bl_rootblks,
426	    kd,
427	    dmmax,
428	    nswdev,
429	    swap_ary,
430	    swap_max,
431	    0,
432	    flags
433	);
434}
435
436static void
437getswapinfo_old(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
438{
439	struct rlist *swapptr;
440	struct rlisthdr swaplist;
441	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
442
443	KGET(NL_SWAPLIST, swaplist);
444
445	swapptr = swaplist.rlh_list;
446
447	while (swapptr) {
448		int	top;
449		int	bottom;
450		int	next_block;
451		int	t;
452		int	v;
453		struct rlist head;
454
455		KGET2(swapptr, &head, sizeof(head), "swapptr");
456
457		top = head.rl_end;
458		bottom = head.rl_start;
459
460		/*
461		 * Handle interleave indexing
462		 */
463
464		while (top / dmmax != bottom / dmmax) {
465			next_block = ((bottom + dmmax) / dmmax);
466
467			t = (bottom / dmmax) % nswdev;
468			v = next_block * dmmax - bottom;
469
470			if (t < ti)
471				swap_ary[t].ksw_used -= dbtoc(v);
472			if (ti >= 0)
473				swap_ary[ti].ksw_used -= dbtoc(v);
474
475			bottom = next_block * dmmax;
476		}
477
478		t = (bottom / dmmax) % nswdev;
479		v = top - bottom + 1;
480
481		if (t < ti)
482			swap_ary[t].ksw_used -= dbtoc(v);
483		if (ti >= 0)
484			swap_ary[ti].ksw_used -= dbtoc(v);
485
486		swapptr = head.rl_next;
487	}
488}
489
490