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bufcache.c revision 1.4 
      1 /*	$NetBSD: bufcache.c,v 1.4 1999/11/27 05:58:04 mrg Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Simon Burge.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #ifndef lint
     41 __RCSID("$NetBSD: bufcache.c,v 1.4 1999/11/27 05:58:04 mrg Exp $");
     42 #endif /* not lint */
     43 
     44 #include <sys/param.h>
     45 #include <sys/buf.h>
     46 #include <sys/mount.h>
     47 #include <sys/queue.h>
     48 #include <sys/time.h>
     49 #include <sys/vnode.h>
     50 
     51 #include <err.h>
     52 #include <kvm.h>
     53 #include <nlist.h>
     54 #include <paths.h>
     55 #include <stdlib.h>
     56 #include <unistd.h>
     57 
     58 #include "systat.h"
     59 #include "extern.h"
     60 
     61 
     62 /*
     63  * Definitions for the buffer free lists (from sys/kern/vfs_bio.c).
     64  */
     65 #define	BQUEUES		4		/* number of free buffer queues */
     66 
     67 #define	BQ_LOCKED	0		/* super-blocks &c */
     68 #define	BQ_LRU		1		/* lru, useful buffers */
     69 #define	BQ_AGE		2		/* rubbish */
     70 #define	BQ_EMPTY	3		/* buffer headers with no memory */
     71 
     72 #define VCACHE_SIZE	50
     73 
     74 struct vcache {
     75 	int vc_age;
     76 	struct vnode *vc_addr;
     77 	struct vnode vc_node;
     78 };
     79 
     80 struct ml_entry {
     81 	int ml_count;
     82 	long ml_size;
     83 	long ml_valid;
     84 	struct mount *ml_addr;
     85 	struct mount ml_mount;
     86 	LIST_ENTRY(ml_entry) ml_entries;
     87 };
     88 
     89 static struct nlist namelist[] = {
     90 #define	X_NBUF		0
     91 	{ "_nbuf" },
     92 #define	X_BUF		1
     93 	{ "_buf" },
     94 #define	X_BUFQUEUES	2
     95 	{ "_bufqueues" },
     96 #define	X_BUFPAGES	3
     97 	{ "_bufpages" },
     98 	{ "" },
     99 };
    100 
    101 static struct vcache vcache[VCACHE_SIZE];
    102 static LIST_HEAD(mount_list, ml_entry) mount_list;
    103 
    104 static int nbuf, bufpages, bufbytes;
    105 static void *bufaddr;
    106 static struct buf *buf = NULL;
    107 static TAILQ_HEAD(bqueues, buf) bufqueues[BQUEUES];
    108 
    109 static void	vc_init __P((void));
    110 static void	ml_init __P((void));
    111 static struct 	vnode *vc_lookup __P((struct vnode *));
    112 static struct 	mount *ml_lookup __P((struct mount *, int, int));
    113 
    114 
    115 WINDOW *
    116 openbufcache()
    117 {
    118 
    119 	return (subwin(stdscr, LINES-5-1, 0, 5, 0));
    120 }
    121 
    122 void
    123 closebufcache(w)
    124 	WINDOW *w;
    125 {
    126 
    127 	if (w == NULL)
    128 		return;
    129 	wclear(w);
    130 	wrefresh(w);
    131 	delwin(w);
    132 	ml_init();		/* Clear out mount list */
    133 }
    134 
    135 void
    136 labelbufcache()
    137 {
    138 	mvwprintw(wnd, 0, 0, "There are %d buffers using %d kBytes of memory.",
    139 	    nbuf, bufbytes / 1024);
    140 	wclrtoeol(wnd);
    141 	wmove(wnd, 1, 0);
    142 	wclrtoeol(wnd);
    143 	mvwaddstr(wnd, 2, 0,
    144 "File System          Bufs used   %   kB in use   %  Bufsize kB   %  Util %");
    145 	wclrtoeol(wnd);
    146 }
    147 
    148 void
    149 showbufcache()
    150 {
    151 	int tbuf, i, lastrow;
    152 	long tvalid, tsize;
    153 	struct ml_entry *ml;
    154 
    155 	tbuf = tvalid = tsize = 0;
    156 	lastrow = 3;	/* Leave room for header. */
    157 	for (i = lastrow, ml = LIST_FIRST(&mount_list); ml != NULL;
    158 	    i++, ml = LIST_NEXT(ml, ml_entries)) {
    159 
    160 		/* Display in window if enough room. */
    161 		if (i < getmaxy(wnd) - 2) {
    162 			mvwprintw(wnd, i, 0, "%-20.20s", ml->ml_addr == NULL ?
    163 			    "NULL" : ml->ml_mount.mnt_stat.f_mntonname);
    164 			wprintw(wnd,
    165 			    "    %6d %3d    %8ld %3d    %8ld %3d     %3d",
    166 			    ml->ml_count,
    167 			    (100 * ml->ml_count) / nbuf,
    168 			    ml->ml_valid / 1024,
    169 			    (100 * ml->ml_valid) / bufbytes,
    170 			    ml->ml_size / 1024,
    171 			    (100 * ml->ml_size) / bufbytes,
    172 			    (100 * ml->ml_valid) / ml->ml_size);
    173 			wclrtoeol(wnd);
    174 			lastrow = i;
    175 		}
    176 
    177 		/* Update statistics. */
    178 		tbuf += ml->ml_count;
    179 		tvalid += ml->ml_valid / 1024;
    180 		tsize += ml->ml_size / 1024;
    181 	}
    182 
    183 	wclrtobot(wnd);
    184 	mvwprintw(wnd, lastrow + 2, 0,
    185 	    "%-20s    %6d %3d    %8d %3d    %8d %3d     %3d",
    186 	    "Total:", tbuf, (100 * tbuf) / nbuf,
    187 	    tvalid, (100 * tvalid * 1024) / bufbytes,
    188 	    tsize, (100 * tsize * 1024) / bufbytes, (100 * tvalid) / tsize);
    189 }
    190 
    191 int
    192 initbufcache()
    193 {
    194 	if (namelist[X_NBUF].n_type == 0) {
    195 		if (kvm_nlist(kd, namelist)) {
    196 			nlisterr(namelist);
    197 			return(0);
    198 		}
    199 		if (namelist[X_NBUF].n_type == 0) {
    200 			error("namelist on %s failed", _PATH_UNIX);
    201 			return(0);
    202 		}
    203 	}
    204 
    205 	NREAD(X_NBUF, &nbuf, sizeof(nbuf));
    206 	NREAD(X_BUFPAGES, &bufpages, sizeof(bufpages));
    207 	bufbytes = bufpages * sysconf(_SC_PAGESIZE);
    208 
    209 	buf = (struct buf *)malloc(nbuf * sizeof(struct buf));
    210 	if (buf == NULL)
    211 		errx(1, "malloc failed\n");
    212 	NREAD(X_BUF, &bufaddr, sizeof(bufaddr));
    213 
    214 	return(1);
    215 }
    216 
    217 void
    218 fetchbufcache()
    219 {
    220 	int i, count;
    221 	struct buf *bp;
    222 	struct vnode *vn;
    223 	struct mount *mt;
    224 	struct ml_entry *ml;
    225 
    226 	/* Re-read bufqueues lists and buffer cache headers */
    227 	NREAD(X_BUFQUEUES, bufqueues, sizeof(bufqueues));
    228 	KREAD(bufaddr, buf, sizeof(struct buf) * nbuf);
    229 
    230 	/* Initialise vnode cache and mount list. */
    231 	vc_init();
    232 	ml_init();
    233 	for (i = 0; i < BQUEUES; i++) {
    234 		for (bp = bufqueues[i].tqh_first; bp != NULL;
    235 		    bp = bp->b_freelist.tqe_next) {
    236 			if (bp != NULL) {
    237 				bp = (struct buf *)((u_long)bp + (u_long)buf -
    238 				    (u_long)bufaddr);
    239 
    240 				if (bp->b_vp != NULL) {
    241 					vn = vc_lookup(bp->b_vp);
    242 					if (vn == NULL)
    243 						errx(1,
    244 						    "vc_lookup returns NULL!\n");
    245 					if (vn->v_mount != NULL)
    246 						mt = ml_lookup(vn->v_mount,
    247 						    bp->b_bufsize,
    248 						    bp->b_bcount);
    249 				}
    250 			}
    251 		}
    252 	}
    253 
    254 	/* simple sort - there's not that many entries */
    255 	do {
    256 		if ((ml = LIST_FIRST(&mount_list)) == NULL ||
    257 		    LIST_NEXT(ml, ml_entries) == NULL)
    258 			break;
    259 
    260 		count = 0;
    261 		for (ml = LIST_FIRST(&mount_list); ml != NULL;
    262 		    ml = LIST_NEXT(ml, ml_entries)) {
    263 			if (LIST_NEXT(ml, ml_entries) == NULL)
    264 				break;
    265 			if (ml->ml_count < LIST_NEXT(ml, ml_entries)->ml_count) {
    266 				ml = LIST_NEXT(ml, ml_entries);
    267 				LIST_REMOVE(ml, ml_entries);
    268 				LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    269 				count++;
    270 			}
    271 		}
    272 	} while (count != 0);
    273 }
    274 
    275 static void
    276 vc_init()
    277 {
    278 	int i;
    279 
    280 	/* vc_addr == NULL for unused cache entry. */
    281 	for (i = 0; i < VCACHE_SIZE; i++)
    282 		vcache[i].vc_addr = NULL;
    283 }
    284 
    285 static void
    286 ml_init()
    287 {
    288 	struct ml_entry *ml;
    289 
    290 	/* Throw out the current mount list and start again. */
    291 	while ((ml = LIST_FIRST(&mount_list)) != NULL) {
    292 		LIST_REMOVE(ml, ml_entries);
    293 		free(ml);
    294 	}
    295 }
    296 
    297 
    298 static struct vnode *
    299 vc_lookup(vaddr)
    300 	struct vnode *vaddr;
    301 {
    302 	struct vnode *ret;
    303 	int i, oldest, match;
    304 
    305 	ret = NULL;
    306 	oldest = match = 0;
    307 	for (i = 0; i < VCACHE_SIZE || vcache[i].vc_addr == NULL; i++) {
    308 		vcache[i].vc_age++;
    309 		if (vcache[i].vc_addr == NULL)
    310 			break;
    311 		if (vcache[i].vc_age < vcache[oldest].vc_age)
    312 			oldest = i;
    313 		if (vcache[i].vc_addr == vaddr) {
    314 			vcache[i].vc_age = 0;
    315 			match = i;
    316 			ret = &vcache[i].vc_node;
    317 		}
    318 	}
    319 
    320 	/* Find an entry in the cache? */
    321 	if (ret != NULL)
    322 		return(ret);
    323 
    324 	/* Go past the end of the cache? */
    325 	if  (i >= VCACHE_SIZE)
    326 		i = oldest;
    327 
    328 	/* Read in new vnode and reset age counter. */
    329 	KREAD(vaddr, &vcache[i].vc_node, sizeof(struct vnode));
    330 	vcache[i].vc_addr = vaddr;
    331 	vcache[i].vc_age = 0;
    332 
    333 	return(&vcache[i].vc_node);
    334 }
    335 
    336 static struct mount *
    337 ml_lookup(maddr, size, valid)
    338 	struct mount *maddr;
    339 	int size, valid;
    340 {
    341 	struct ml_entry *ml;
    342 
    343 	for (ml = LIST_FIRST(&mount_list); ml != NULL;
    344 	    ml = LIST_NEXT(ml, ml_entries))
    345 		if (ml->ml_addr == maddr) {
    346 			ml->ml_count++;
    347 			ml->ml_size += size;
    348 			ml->ml_valid += valid;
    349 			if (ml->ml_addr == NULL)
    350 				return(NULL);
    351 			else
    352 				return(&ml->ml_mount);
    353 		}
    354 
    355 	if ((ml = malloc(sizeof(struct ml_entry))) == NULL)
    356 		errx(1, "out of memory\n");
    357 	LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    358 	ml->ml_count = 1;
    359 	ml->ml_size = size;
    360 	ml->ml_valid = valid;
    361 	ml->ml_addr = maddr;
    362 	if (maddr == NULL)
    363 		return(NULL);
    364 
    365 	KREAD(maddr, &ml->ml_mount, sizeof(struct mount));
    366 	return(&ml->ml_mount);
    367 }
    368