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bufcache.c revision 1.1 
      1 /*	$NetBSD: bufcache.c,v 1.1 1999/11/15 06:16:56 simonb 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 1.1 1999/11/15 06:16:56 simonb 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 
     57 #include "systat.h"
     58 #include "extern.h"
     59 
     60 
     61 /*
     62  * Definitions for the buffer free lists (from sys/kern/vfs_bio.c).
     63  */
     64 #define	BQUEUES		4		/* number of free buffer queues */
     65 
     66 #define	BQ_LOCKED	0		/* super-blocks &c */
     67 #define	BQ_LRU		1		/* lru, useful buffers */
     68 #define	BQ_AGE		2		/* rubbish */
     69 #define	BQ_EMPTY	3		/* buffer headers with no memory */
     70 
     71 #define VCACHE_SIZE	50
     72 
     73 struct vcache {
     74 	int vc_age;
     75 	struct vnode *vc_addr;
     76 	struct vnode vc_node;
     77 };
     78 
     79 struct ml_entry {
     80 	int ml_count;
     81 	long ml_size;
     82 	long ml_valid;
     83 	struct mount *ml_addr;
     84 	struct mount ml_mount;
     85 	LIST_ENTRY(ml_entry) ml_entries;
     86 };
     87 
     88 static struct nlist namelist[] = {
     89 #define	X_NBUF		0
     90 	{ "_nbuf" },
     91 #define	X_BUF		1
     92 	{ "_buf" },
     93 #define	X_BUFQUEUES	2
     94 	{ "_bufqueues" },
     95 #define	X_BUFPAGES	3
     96 	{ "_bufpages" },
     97 	{ "" },
     98 };
     99 
    100 static struct vcache vcache[VCACHE_SIZE];
    101 static LIST_HEAD(mount_list, ml_entry) mount_list;
    102 
    103 static int nbuf, bufpages;
    104 static void *bufaddr;
    105 static struct buf *buf = NULL;
    106 static TAILQ_HEAD(bqueues, buf) bufqueues[BQUEUES];
    107 
    108 static void	vc_init __P((void));
    109 static void	ml_init __P((void));
    110 static struct 	vnode *vc_lookup __P((struct vnode *));
    111 static struct 	mount *ml_lookup __P((struct mount *, int, int));
    112 
    113 
    114 WINDOW *
    115 openbufcache()
    116 {
    117 
    118 	return (subwin(stdscr, LINES-5-1, 0, 5, 0));
    119 }
    120 
    121 void
    122 closebufcache(w)
    123 	WINDOW *w;
    124 {
    125 
    126 	if (w == NULL)
    127 		return;
    128 	wclear(w);
    129 	wrefresh(w);
    130 	delwin(w);
    131 	ml_init();		/* Clear out mount list */
    132 	if (buf != NULL)
    133 		free(buf);
    134 }
    135 
    136 void
    137 labelbufcache()
    138 {
    139 	mvwprintw(wnd, 0, 0, "There are %d buffers using %d kBytes of memory.",
    140 	    nbuf, bufpages * CLBYTES / 1024);
    141 	wclrtoeol(wnd);
    142 	wmove(wnd, 1, 0);
    143 	wclrtoeol(wnd);
    144 	mvwaddstr(wnd, 2, 0,
    145 	    "File System          Bufs used   kB in use  Bufsize kB");
    146 	wclrtoeol(wnd);
    147 }
    148 
    149 void
    150 showbufcache()
    151 {
    152 	int tbuf, i, lastrow;
    153 	long tvalid, tsize;
    154 	struct ml_entry *ml;
    155 
    156 	tbuf = tvalid = tsize = 0;
    157 	lastrow = 3;	/* Leave room for header. */
    158 	for (i = lastrow, ml = LIST_FIRST(&mount_list); ml != NULL;
    159 	    i++, ml = LIST_NEXT(ml, ml_entries)) {
    160 
    161 		/* Display in window if enough room. */
    162 		if (i < getmaxy(wnd) - 2) {
    163 			mvwprintw(wnd, i, 0, "%-20.20s", ml->ml_addr == NULL ?
    164 			    "NULL" : ml->ml_mount.mnt_stat.f_mntonname);
    165 			wprintw(wnd, "    %6d    %8ld    %8ld", ml->ml_count,
    166 			    ml->ml_valid / 1024, ml->ml_size / 1024);
    167 			wclrtoeol(wnd);
    168 			lastrow = i;
    169 		}
    170 
    171 		/* Update statistics. */
    172 		tbuf += ml->ml_count;
    173 		tvalid += ml->ml_valid / 1024;
    174 		tsize += ml->ml_size / 1024;
    175 	}
    176 
    177 	wclrtobot(wnd);
    178 	mvwprintw(wnd, lastrow + 2, 0, "%-20s    %6d    %8d    %8d",
    179 	    "Total:", tbuf, tvalid, tsize);
    180 }
    181 
    182 int
    183 initbufcache()
    184 {
    185 	if (namelist[X_NBUF].n_type == 0) {
    186 		if (kvm_nlist(kd, namelist)) {
    187 			nlisterr(namelist);
    188 			return(0);
    189 		}
    190 		if (namelist[X_NBUF].n_type == 0) {
    191 			error("namelist on %s failed", _PATH_UNIX);
    192 			return(0);
    193 		}
    194 	}
    195 
    196 	NREAD(X_NBUF, &nbuf, sizeof(nbuf));
    197 	NREAD(X_BUFPAGES, &bufpages, sizeof(bufpages));
    198 
    199 	buf = (struct buf *)malloc(nbuf * sizeof(struct buf));
    200 	if (buf == NULL)
    201 		errx(1, "malloc failed\n");
    202 	NREAD(X_BUF, &bufaddr, sizeof(bufaddr));
    203 
    204 	return(1);
    205 }
    206 
    207 void
    208 fetchbufcache()
    209 {
    210 	int i, count;
    211 	struct buf *bp;
    212 	struct vnode *vn;
    213 	struct mount *mt;
    214 	struct ml_entry *ml;
    215 
    216 	/* Re-read bufqueues lists and buffer cache headers */
    217 	NREAD(X_BUFQUEUES, bufqueues, sizeof(bufqueues));
    218 	KREAD(bufaddr, buf, sizeof(struct buf) * nbuf);
    219 
    220 	/* Initialise vnode cache and mount list. */
    221 	vc_init();
    222 	ml_init();
    223 	for (i = 0; i < BQUEUES; i++) {
    224 		for (bp = bufqueues[i].tqh_first; bp != NULL;
    225 		    bp = bp->b_freelist.tqe_next) {
    226 			if (bp != NULL) {
    227 				bp = (struct buf *)((u_long)bp + (u_long)buf -
    228 				    (u_long)bufaddr);
    229 
    230 				if (bp->b_vp != NULL) {
    231 					vn = vc_lookup(bp->b_vp);
    232 					if (vn == NULL)
    233 						errx(1,
    234 						    "vc_lookup returns NULL!\n");
    235 					if (vn->v_mount != NULL)
    236 						mt = ml_lookup(vn->v_mount,
    237 						    bp->b_bufsize,
    238 						    bp->b_bcount);
    239 				}
    240 			}
    241 		}
    242 	}
    243 
    244 	/* simple sort - there's not that many entries */
    245 	do {
    246 		if ((ml = LIST_FIRST(&mount_list)) == NULL ||
    247 		    LIST_NEXT(ml, ml_entries) == NULL)
    248 			break;
    249 
    250 		count = 0;
    251 		for (ml = LIST_FIRST(&mount_list); ml != NULL;
    252 		    ml = LIST_NEXT(ml, ml_entries)) {
    253 			if (LIST_NEXT(ml, ml_entries) == NULL)
    254 				break;
    255 			if (ml->ml_count < LIST_NEXT(ml, ml_entries)->ml_count) {
    256 				ml = LIST_NEXT(ml, ml_entries);
    257 				LIST_REMOVE(ml, ml_entries);
    258 				LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    259 				count++;
    260 			}
    261 		}
    262 	} while (count != 0);
    263 }
    264 
    265 static void
    266 vc_init()
    267 {
    268 	int i;
    269 
    270 	/* vc_addr == NULL for unused cache entry. */
    271 	for (i = 0; i < VCACHE_SIZE; i++)
    272 		vcache[i].vc_addr = NULL;
    273 }
    274 
    275 static void
    276 ml_init()
    277 {
    278 	struct ml_entry *ml;
    279 
    280 	/* Throw out the current mount list and start again. */
    281 	while ((ml = LIST_FIRST(&mount_list)) != NULL) {
    282 		LIST_REMOVE(ml, ml_entries);
    283 		free(ml);
    284 	}
    285 }
    286 
    287 
    288 static struct vnode *
    289 vc_lookup(vaddr)
    290 	struct vnode *vaddr;
    291 {
    292 	struct vnode *ret;
    293 	int i, oldest, match;
    294 
    295 	ret = NULL;
    296 	oldest = match = 0;
    297 	for (i = 0; i < VCACHE_SIZE || vcache[i].vc_addr == NULL; i++) {
    298 		vcache[i].vc_age++;
    299 		if (vcache[i].vc_addr == NULL)
    300 			break;
    301 		if (vcache[i].vc_age < vcache[oldest].vc_age)
    302 			oldest = i;
    303 		if (vcache[i].vc_addr == vaddr) {
    304 			vcache[i].vc_age = 0;
    305 			match = i;
    306 			ret = &vcache[i].vc_node;
    307 		}
    308 	}
    309 
    310 	/* Find an entry in the cache? */
    311 	if (ret != NULL)
    312 		return(ret);
    313 
    314 	/* Go past the end of the cache? */
    315 	if  (i >= VCACHE_SIZE)
    316 		i = oldest;
    317 
    318 	/* Read in new vnode and reset age counter. */
    319 	KREAD(vaddr, &vcache[i].vc_node, sizeof(struct vnode));
    320 	vcache[i].vc_addr = vaddr;
    321 	vcache[i].vc_age = 0;
    322 
    323 	return(&vcache[i].vc_node);
    324 }
    325 
    326 static struct mount *
    327 ml_lookup(maddr, size, valid)
    328 	struct mount *maddr;
    329 	int size, valid;
    330 {
    331 	struct ml_entry *ml;
    332 
    333 	for (ml = LIST_FIRST(&mount_list); ml != NULL;
    334 	    ml = LIST_NEXT(ml, ml_entries))
    335 		if (ml->ml_addr == maddr) {
    336 			ml->ml_count++;
    337 			ml->ml_size += size;
    338 			ml->ml_valid += valid;
    339 			if (ml->ml_addr == NULL)
    340 				return(NULL);
    341 			else
    342 				return(&ml->ml_mount);
    343 		}
    344 
    345 	if ((ml = malloc(sizeof(struct ml_entry))) == NULL)
    346 		errx(1, "out of memory\n");
    347 	LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    348 	ml->ml_count = 1;
    349 	ml->ml_size = size;
    350 	ml->ml_valid = valid;
    351 	ml->ml_addr = maddr;
    352 	if (maddr == NULL)
    353 		return(NULL);
    354 
    355 	KREAD(maddr, &ml->ml_mount, sizeof(struct mount));
    356 	return(&ml->ml_mount);
    357 }
    358