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bufcache.c revision 1.6 
      1 /*	$NetBSD: bufcache.c,v 1.6 2000/02/14 05:35:21 soren 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 1.6 2000/02/14 05:35:21 soren 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, bufkb;
    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, bufkb);
    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, (100 * ml->ml_count) / nbuf,
    167 			    ml->ml_valid, (100 * ml->ml_valid) / bufkb,
    168 			    ml->ml_size, (100 * ml->ml_size) / bufkb,
    169 			    (100 * ml->ml_valid) / ml->ml_size);
    170 			wclrtoeol(wnd);
    171 			lastrow = i;
    172 		}
    173 
    174 		/* Update statistics. */
    175 		tbuf += ml->ml_count;
    176 		tvalid += ml->ml_valid;
    177 		tsize += ml->ml_size;
    178 	}
    179 
    180 	wclrtobot(wnd);
    181 	mvwprintw(wnd, lastrow + 2, 0,
    182 	    "%-20s    %6d %3d    %8d %3d    %8d %3d     %3d",
    183 	    "Total:", tbuf, (100 * tbuf) / nbuf,
    184 	    tvalid, (100 * tvalid) / bufkb,
    185 	    tsize, (100 * tsize) / bufkb, (100 * tvalid) / tsize);
    186 }
    187 
    188 int
    189 initbufcache()
    190 {
    191 	if (namelist[X_NBUF].n_type == 0) {
    192 		if (kvm_nlist(kd, namelist)) {
    193 			nlisterr(namelist);
    194 			return(0);
    195 		}
    196 		if (namelist[X_NBUF].n_type == 0) {
    197 			error("namelist on %s failed", _PATH_UNIX);
    198 			return(0);
    199 		}
    200 	}
    201 
    202 	NREAD(X_NBUF, &nbuf, sizeof(nbuf));
    203 	NREAD(X_BUFPAGES, &bufpages, sizeof(bufpages));
    204 	bufkb = bufpages * sysconf(_SC_PAGESIZE) / 1024;
    205 
    206 	if ((buf = malloc(nbuf * sizeof(struct buf))) == NULL) {
    207 		error("malloc failed");
    208 		die(0);
    209 	}
    210 	NREAD(X_BUF, &bufaddr, sizeof(bufaddr));
    211 
    212 	return(1);
    213 }
    214 
    215 void
    216 fetchbufcache()
    217 {
    218 	int i, count;
    219 	struct buf *bp;
    220 	struct vnode *vn;
    221 	struct mount *mt;
    222 	struct ml_entry *ml;
    223 
    224 	/* Re-read bufqueues lists and buffer cache headers */
    225 	NREAD(X_BUFQUEUES, bufqueues, sizeof(bufqueues));
    226 	KREAD(bufaddr, buf, sizeof(struct buf) * nbuf);
    227 
    228 	/* Initialise vnode cache and mount list. */
    229 	vc_init();
    230 	ml_init();
    231 	for (i = 0; i < BQUEUES; i++) {
    232 		for (bp = bufqueues[i].tqh_first; bp != NULL;
    233 		    bp = bp->b_freelist.tqe_next) {
    234 			if (bp != NULL) {
    235 				bp = (struct buf *)((u_long)bp + (u_long)buf -
    236 				    (u_long)bufaddr);
    237 
    238 				if (bp->b_vp != NULL) {
    239 					vn = vc_lookup(bp->b_vp);
    240 					if (vn == NULL)
    241 						errx(1,
    242 						    "vc_lookup returns NULL!\n");
    243 					if (vn->v_mount != NULL)
    244 						mt = ml_lookup(vn->v_mount,
    245 						    bp->b_bufsize,
    246 						    bp->b_bcount);
    247 				}
    248 			}
    249 		}
    250 	}
    251 
    252 	/* simple sort - there's not that many entries */
    253 	do {
    254 		if ((ml = LIST_FIRST(&mount_list)) == NULL ||
    255 		    LIST_NEXT(ml, ml_entries) == NULL)
    256 			break;
    257 
    258 		count = 0;
    259 		for (ml = LIST_FIRST(&mount_list); ml != NULL;
    260 		    ml = LIST_NEXT(ml, ml_entries)) {
    261 			if (LIST_NEXT(ml, ml_entries) == NULL)
    262 				break;
    263 			if (ml->ml_count < LIST_NEXT(ml, ml_entries)->ml_count) {
    264 				ml = LIST_NEXT(ml, ml_entries);
    265 				LIST_REMOVE(ml, ml_entries);
    266 				LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    267 				count++;
    268 			}
    269 		}
    270 	} while (count != 0);
    271 }
    272 
    273 static void
    274 vc_init()
    275 {
    276 	int i;
    277 
    278 	/* vc_addr == NULL for unused cache entry. */
    279 	for (i = 0; i < VCACHE_SIZE; i++)
    280 		vcache[i].vc_addr = NULL;
    281 }
    282 
    283 static void
    284 ml_init()
    285 {
    286 	struct ml_entry *ml;
    287 
    288 	/* Throw out the current mount list and start again. */
    289 	while ((ml = LIST_FIRST(&mount_list)) != NULL) {
    290 		LIST_REMOVE(ml, ml_entries);
    291 		free(ml);
    292 	}
    293 }
    294 
    295 
    296 static struct vnode *
    297 vc_lookup(vaddr)
    298 	struct vnode *vaddr;
    299 {
    300 	struct vnode *ret;
    301 	int i, oldest, match;
    302 
    303 	ret = NULL;
    304 	oldest = match = 0;
    305 	for (i = 0; i < VCACHE_SIZE || vcache[i].vc_addr == NULL; i++) {
    306 		vcache[i].vc_age++;
    307 		if (vcache[i].vc_addr == NULL)
    308 			break;
    309 		if (vcache[i].vc_age < vcache[oldest].vc_age)
    310 			oldest = i;
    311 		if (vcache[i].vc_addr == vaddr) {
    312 			vcache[i].vc_age = 0;
    313 			match = i;
    314 			ret = &vcache[i].vc_node;
    315 		}
    316 	}
    317 
    318 	/* Find an entry in the cache? */
    319 	if (ret != NULL)
    320 		return(ret);
    321 
    322 	/* Go past the end of the cache? */
    323 	if  (i >= VCACHE_SIZE)
    324 		i = oldest;
    325 
    326 	/* Read in new vnode and reset age counter. */
    327 	KREAD(vaddr, &vcache[i].vc_node, sizeof(struct vnode));
    328 	vcache[i].vc_addr = vaddr;
    329 	vcache[i].vc_age = 0;
    330 
    331 	return(&vcache[i].vc_node);
    332 }
    333 
    334 static struct mount *
    335 ml_lookup(maddr, size, valid)
    336 	struct mount *maddr;
    337 	int size, valid;
    338 {
    339 	struct ml_entry *ml;
    340 
    341 	for (ml = LIST_FIRST(&mount_list); ml != NULL;
    342 	    ml = LIST_NEXT(ml, ml_entries))
    343 		if (ml->ml_addr == maddr) {
    344 			ml->ml_count++;
    345 			ml->ml_size += size / 1024;
    346 			ml->ml_valid += valid / 1024;
    347 			if (ml->ml_addr == NULL)
    348 				return(NULL);
    349 			else
    350 				return(&ml->ml_mount);
    351 		}
    352 
    353 	if ((ml = malloc(sizeof(struct ml_entry))) == NULL) {
    354 		error("out of memory");
    355 		die(0);
    356 	}
    357 	LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    358 	ml->ml_count = 1;
    359 	ml->ml_size = size / 1024;
    360 	ml->ml_valid = valid / 1024;
    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