kvm_getswapinfo.c revision 44021 
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 1.5 1999/02/06 06:31:57 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_type != N_UNDF)
131			type = 1;
132
133		if (kvm_swap_nl[NL_SWAPBLIST].n_type != N_UNDF)
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			 * The first dmmax is never allocating to avoid
180			 * trashing the disklabels
181			 */
182
183			if (type == 1)
184				ttl = dbtoc(swinfo.sw_nblks - dmmax);
185			else
186				ttl = swinfo.sw_nblks - dmmax;
187
188			if (ttl == 0)
189				continue;
190
191			if (i < ti) {
192				swap_ary[i].ksw_total = ttl;
193				swap_ary[i].ksw_used = ttl;
194				swap_ary[i].ksw_flags = swinfo.sw_flags;
195				if (swinfo.sw_dev == NODEV) {
196					snprintf(
197					    swap_ary[i].ksw_devname,
198					    sizeof(swap_ary[i].ksw_devname),
199					    "%s",
200					    "[NFS swap]"
201					);
202				} else {
203					snprintf(
204					    swap_ary[i].ksw_devname,
205					    sizeof(swap_ary[i].ksw_devname),
206					    "%s%s",
207					    ((flags & SWIF_DEV_PREFIX) ? "/dev/" : ""),
208					    devname(swinfo.sw_dev, S_IFBLK)
209					);
210				}
211			}
212			if (ti >= 0) {
213				swap_ary[ti].ksw_total += ttl;
214				swap_ary[ti].ksw_used += ttl;
215			}
216		}
217	}
218
219	switch(type) {
220	case 1:
221		getswapinfo_old(kd, swap_ary, swap_max, flags);
222		break;
223	case 2:
224		getswapinfo_radix(kd, swap_ary, swap_max, flags);
225		break;
226	default:
227		ti = -1;
228		break;
229	}
230	return(ti);
231}
232
233/*
234 * scanradix() - support routine for radix scanner
235 */
236
237#define TABME	tab, tab, ""
238
239static int
240scanradix(
241	blmeta_t *scan,
242	daddr_t blk,
243	daddr_t radix,
244	daddr_t skip,
245	daddr_t count,
246	kvm_t *kd,
247	int dmmax,
248	int nswdev,
249	struct kvm_swap *swap_ary,
250	int swap_max,
251	int tab,
252	int flags
253) {
254	blmeta_t meta;
255	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
256
257	KGET2(scan, &meta, sizeof(meta), "blmeta_t");
258
259	/*
260	 * Terminator
261	 */
262	if (meta.bm_bighint == (daddr_t)-1) {
263		if (flags & SWIF_DUMP_TREE) {
264			printf("%*.*s(0x%06x,%d) Terminator\n",
265			    TABME,
266			    blk,
267			    radix
268			);
269		}
270		return(-1);
271	}
272
273	if (radix == BLIST_BMAP_RADIX) {
274		/*
275		 * Leaf bitmap
276		 */
277		int i;
278
279		if (flags & SWIF_DUMP_TREE) {
280			printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
281			    TABME,
282			    blk,
283			    radix,
284			    (int)meta.u.bmu_bitmap,
285			    meta.bm_bighint
286			);
287		}
288
289		/*
290		 * If not all allocated, count.
291		 */
292		if (meta.u.bmu_bitmap != 0) {
293			for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
294				/*
295				 * A 0 bit means allocated
296				 */
297				if ((meta.u.bmu_bitmap & (1 << i))) {
298					int t = 0;
299
300					if (nswdev)
301						t = (blk + i) / dmmax % nswdev;
302					if (t < ti)
303						--swap_ary[t].ksw_used;
304					if (ti >= 0)
305						--swap_ary[ti].ksw_used;
306				}
307			}
308		}
309	} else if (meta.u.bmu_avail == radix) {
310		/*
311		 * Meta node if all free
312		 */
313		if (flags & SWIF_DUMP_TREE) {
314			printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
315			    TABME,
316			    blk,
317			    radix,
318			    (int)meta.u.bmu_avail,
319			    meta.bm_bighint
320			);
321		}
322		/*
323		 * Note: both dmmax and radix are powers of 2.  However, dmmax
324		 * may be larger then radix so use a smaller increment if
325		 * necessary.
326		 */
327		{
328			int t;
329			int tinc = dmmax;
330
331			while (tinc > radix)
332				tinc >>= 1;
333
334			for (t = blk; t < blk + radix; t += tinc) {
335				int u = (nswdev) ? (t / dmmax % nswdev) : 0;
336
337				if (u < ti)
338					swap_ary[u].ksw_used -= tinc;
339				if (ti >= 0)
340					swap_ary[ti].ksw_used -= tinc;
341			}
342		}
343	} else if (meta.u.bmu_avail == 0) {
344		/*
345		 * Meta node if all used
346		 */
347		if (flags & SWIF_DUMP_TREE) {
348			printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
349			    TABME,
350			    blk,
351			    radix,
352			    (int)meta.u.bmu_avail,
353			    meta.bm_bighint
354			);
355		}
356	} else {
357		/*
358		 * Meta node if not all free
359		 */
360		int i;
361		int next_skip;
362
363		if (flags & SWIF_DUMP_TREE) {
364			printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
365			    TABME,
366			    blk,
367			    radix,
368			    (int)meta.u.bmu_avail,
369			    meta.bm_bighint
370			);
371		}
372
373		radix >>= BLIST_META_RADIX_SHIFT;
374		next_skip = skip >> BLIST_META_RADIX_SHIFT;
375
376		for (i = 1; i <= skip; i += next_skip) {
377			int r;
378			daddr_t vcount = (count > radix) ? radix : count;
379
380			r = scanradix(
381			    &scan[i],
382			    blk,
383			    radix,
384			    next_skip - 1,
385			    vcount,
386			    kd,
387			    dmmax,
388			    nswdev,
389			    swap_ary,
390			    swap_max,
391			    tab + 4,
392			    flags
393			);
394			if (r < 0)
395				break;
396			blk += radix;
397		}
398		if (flags & SWIF_DUMP_TREE) {
399			printf("%*.*s}\n", TABME);
400		}
401	}
402	return(0);
403}
404
405static void
406getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
407{
408	struct blist *swapblist = NULL;
409	struct blist blcopy = { 0 };
410
411	KGET(NL_SWAPBLIST, swapblist);
412
413	if (swapblist == NULL) {
414		if (flags & SWIF_DUMP_TREE)
415			printf("radix tree: NULL - no swap in system\n");
416		return;
417	}
418
419	KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
420
421	if (flags & SWIF_DUMP_TREE) {
422		printf("radix tree: %d/%d/%d blocks, %dK wired\n",
423			blcopy.bl_free,
424			blcopy.bl_blocks,
425			blcopy.bl_radix,
426			(blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
427			    1024
428		);
429	}
430	scanradix(
431	    blcopy.bl_root,
432	    0,
433	    blcopy.bl_radix,
434	    blcopy.bl_skip,
435	    blcopy.bl_rootblks,
436	    kd,
437	    dmmax,
438	    nswdev,
439	    swap_ary,
440	    swap_max,
441	    0,
442	    flags
443	);
444}
445
446static void
447getswapinfo_old(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
448{
449	struct rlist *swapptr;
450	struct rlisthdr swaplist;
451	int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
452
453	KGET(NL_SWAPLIST, swaplist);
454
455	swapptr = swaplist.rlh_list;
456
457	while (swapptr) {
458		int	top;
459		int	bottom;
460		int	next_block;
461		int	t;
462		int	v;
463		struct rlist head;
464
465		KGET2(swapptr, &head, sizeof(head), "swapptr");
466
467		top = head.rl_end;
468		bottom = head.rl_start;
469
470		/*
471		 * Handle interleave indexing
472		 */
473
474		while (top / dmmax != bottom / dmmax) {
475			next_block = ((bottom + dmmax) / dmmax);
476
477			t = (bottom / dmmax) % nswdev;
478			v = next_block * dmmax - bottom;
479
480			if (t < ti)
481				swap_ary[t].ksw_used -= dbtoc(v);
482			if (ti >= 0)
483				swap_ary[ti].ksw_used -= dbtoc(v);
484
485			bottom = next_block * dmmax;
486		}
487
488		t = (bottom / dmmax) % nswdev;
489		v = top - bottom + 1;
490
491		if (t < ti)
492			swap_ary[t].ksw_used -= dbtoc(v);
493		if (ti >= 0)
494			swap_ary[ti].ksw_used -= dbtoc(v);
495
496		swapptr = head.rl_next;
497	}
498}
499
500