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bufcache.c revision 1.10 
      1 /*	$NetBSD: bufcache.c,v 1.10 2000/12/01 02:19:43 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 1.10 2000/12/01 02:19:43 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/sysctl.h>
     48 #include <sys/vnode.h>
     49 
     50 #include <uvm/uvm_extern.h>
     51 
     52 #include <err.h>
     53 #include <errno.h>
     54 #include <kvm.h>
     55 #include <nlist.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <unistd.h>
     59 
     60 #include "systat.h"
     61 #include "extern.h"
     62 
     63 /*
     64  * Definitions for the buffer free lists (from sys/kern/vfs_bio.c).
     65  */
     66 #define	BQUEUES		4		/* number of free buffer queues */
     67 
     68 #define	BQ_LOCKED	0		/* super-blocks &c */
     69 #define	BQ_LRU		1		/* lru, useful buffers */
     70 #define	BQ_AGE		2		/* rubbish */
     71 #define	BQ_EMPTY	3		/* buffer headers with no memory */
     72 
     73 #define VCACHE_SIZE	50
     74 
     75 struct vcache {
     76 	int vc_age;
     77 	struct vnode *vc_addr;
     78 	struct vnode vc_node;
     79 };
     80 
     81 struct ml_entry {
     82 	int ml_count;
     83 	long ml_size;
     84 	long ml_valid;
     85 	struct mount *ml_addr;
     86 	struct mount ml_mount;
     87 	LIST_ENTRY(ml_entry) ml_entries;
     88 };
     89 
     90 static struct nlist namelist[] = {
     91 #define	X_NBUF		0
     92 	{ "_nbuf" },
     93 #define	X_BUF		1
     94 	{ "_buf" },
     95 #define	X_BUFQUEUES	2
     96 	{ "_bufqueues" },
     97 #define	X_BUFPAGES	3
     98 	{ "_bufpages" },
     99 	{ "" },
    100 };
    101 
    102 static struct vcache vcache[VCACHE_SIZE];
    103 static LIST_HEAD(mount_list, ml_entry) mount_list;
    104 
    105 static int nbuf, bufpages, bufkb;
    106 static struct uvmexp_sysctl uvmexp;
    107 static void *bufaddr;
    108 static struct buf *buf = NULL;
    109 static TAILQ_HEAD(bqueues, buf) bufqueues[BQUEUES];
    110 
    111 static void	vc_init(void);
    112 static void	ml_init(void);
    113 static struct 	vnode *vc_lookup(struct vnode *);
    114 static struct 	mount *ml_lookup(struct mount *, int, int);
    115 
    116 
    117 WINDOW *
    118 openbufcache(void)
    119 {
    120 
    121 	return (subwin(stdscr, LINES-5-1, 0, 5, 0));
    122 }
    123 
    124 void
    125 closebufcache(WINDOW *w)
    126 {
    127 
    128 	if (w == NULL)
    129 		return;
    130 	wclear(w);
    131 	wrefresh(w);
    132 	delwin(w);
    133 	ml_init();		/* Clear out mount list */
    134 }
    135 
    136 void
    137 labelbufcache(void)
    138 {
    139 	mvwprintw(wnd, 0, 0,
    140 	    "There are %d metadata buffers using %d kBytes of memory.",
    141 	    nbuf, bufkb);
    142 	wclrtoeol(wnd);
    143 	wmove(wnd, 1, 0);
    144 	wmove(wnd, 2, 0);
    145 	wclrtoeol(wnd);
    146 	mvwaddstr(wnd, 3, 0,
    147 "File System          Bufs used   %   kB in use   %  Bufsize kB   %  Util %");
    148 	wclrtoeol(wnd);
    149 }
    150 
    151 void
    152 showbufcache(void)
    153 {
    154 	int tbuf, i, lastrow;
    155 	long tvalid, tsize;
    156 	struct ml_entry *ml;
    157 
    158 	mvwprintw(wnd, 1, 0,
    159 	    "There are %llu pages for vnode page cache using %llu kBytes of memory.",
    160 	    (long long)uvmexp.vnodepages,
    161 	    (long long) uvmexp.vnodepages * getpagesize() / 1024);
    162 	wclrtoeol(wnd);
    163 
    164 	tbuf = tvalid = tsize = 0;
    165 	lastrow = 4;	/* Leave room for header. */
    166 	for (i = lastrow, ml = LIST_FIRST(&mount_list); ml != NULL;
    167 	    i++, ml = LIST_NEXT(ml, ml_entries)) {
    168 
    169 		/* Display in window if enough room. */
    170 		if (i < getmaxy(wnd) - 2) {
    171 			mvwprintw(wnd, i, 0, "%-20.20s", ml->ml_addr == NULL ?
    172 			    "NULL" : ml->ml_mount.mnt_stat.f_mntonname);
    173 			wprintw(wnd,
    174 			    "    %6d %3d    %8ld %3ld    %8ld %3ld     %3ld",
    175 			    ml->ml_count, (100 * ml->ml_count) / nbuf,
    176 			    ml->ml_valid, (100 * ml->ml_valid) / bufkb,
    177 			    ml->ml_size, (100 * ml->ml_size) / bufkb,
    178 			    (100 * ml->ml_valid) / ml->ml_size);
    179 			wclrtoeol(wnd);
    180 			lastrow = i;
    181 		}
    182 
    183 		/* Update statistics. */
    184 		tbuf += ml->ml_count;
    185 		tvalid += ml->ml_valid;
    186 		tsize += ml->ml_size;
    187 	}
    188 
    189 	wclrtobot(wnd);
    190 	mvwprintw(wnd, lastrow + 2, 0,
    191 	    "%-20s    %6d %3d    %8ld %3ld    %8ld %3ld     %3ld",
    192 	    "Total:", tbuf, (100 * tbuf) / nbuf,
    193 	    tvalid, (100 * tvalid) / bufkb,
    194 	    tsize, (100 * tsize) / bufkb, (100 * tvalid) / tsize);
    195 }
    196 
    197 int
    198 initbufcache(void)
    199 {
    200 	if (namelist[X_NBUF].n_type == 0) {
    201 		if (kvm_nlist(kd, namelist)) {
    202 			nlisterr(namelist);
    203 			return(0);
    204 		}
    205 		if (namelist[X_NBUF].n_type == 0) {
    206 			error("No namelist");
    207 			return(0);
    208 		}
    209 	}
    210 
    211 	NREAD(X_NBUF, &nbuf, sizeof(nbuf));
    212 	NREAD(X_BUFPAGES, &bufpages, sizeof(bufpages));
    213 	bufkb = bufpages * sysconf(_SC_PAGESIZE) / 1024;
    214 
    215 	if ((buf = malloc(nbuf * sizeof(struct buf))) == NULL) {
    216 		error("malloc failed");
    217 		die(0);
    218 	}
    219 	NREAD(X_BUF, &bufaddr, sizeof(bufaddr));
    220 
    221 	return(1);
    222 }
    223 
    224 void
    225 fetchbufcache(void)
    226 {
    227 	int i, count, mib[2];
    228 	size_t size;
    229 	struct buf *bp;
    230 	struct vnode *vn;
    231 	struct mount *mt;
    232 	struct ml_entry *ml;
    233 
    234 	/* Re-read pages used for vnodes */
    235 	size = sizeof(uvmexp);
    236 	mib[0] = CTL_VM;
    237 	mib[1] = VM_UVMEXP2;
    238 	if (sysctl(mib, 2, &uvmexp, &size, NULL, 0) < 0) {
    239 		error("can't get uvmexp: %s\n", strerror(errno));
    240 		memset(&uvmexp, 0, sizeof(uvmexp));
    241 	}
    242 
    243 	/* Re-read bufqueues lists and buffer cache headers */
    244 	NREAD(X_BUFQUEUES, bufqueues, sizeof(bufqueues));
    245 	KREAD(bufaddr, buf, sizeof(struct buf) * nbuf);
    246 
    247 	/* Initialise vnode cache and mount list. */
    248 	vc_init();
    249 	ml_init();
    250 	for (i = 0; i < BQUEUES; i++) {
    251 		for (bp = bufqueues[i].tqh_first; bp != NULL;
    252 		    bp = bp->b_freelist.tqe_next) {
    253 			if (bp != NULL) {
    254 				bp = (struct buf *)((u_long)bp + (u_long)buf -
    255 				    (u_long)bufaddr);
    256 
    257 				if (bp->b_vp != NULL) {
    258 					vn = vc_lookup(bp->b_vp);
    259 					if (vn == NULL)
    260 						errx(1,
    261 						    "vc_lookup returns NULL!\n");
    262 					if (vn->v_mount != NULL)
    263 						mt = ml_lookup(vn->v_mount,
    264 						    bp->b_bufsize,
    265 						    bp->b_bcount);
    266 				}
    267 			}
    268 		}
    269 	}
    270 
    271 	/* simple sort - there's not that many entries */
    272 	do {
    273 		if ((ml = LIST_FIRST(&mount_list)) == NULL ||
    274 		    LIST_NEXT(ml, ml_entries) == NULL)
    275 			break;
    276 
    277 		count = 0;
    278 		for (ml = LIST_FIRST(&mount_list); ml != NULL;
    279 		    ml = LIST_NEXT(ml, ml_entries)) {
    280 			if (LIST_NEXT(ml, ml_entries) == NULL)
    281 				break;
    282 			if (ml->ml_count < LIST_NEXT(ml, ml_entries)->ml_count) {
    283 				ml = LIST_NEXT(ml, ml_entries);
    284 				LIST_REMOVE(ml, ml_entries);
    285 				LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    286 				count++;
    287 			}
    288 		}
    289 	} while (count != 0);
    290 }
    291 
    292 static void
    293 vc_init(void)
    294 {
    295 	int i;
    296 
    297 	/* vc_addr == NULL for unused cache entry. */
    298 	for (i = 0; i < VCACHE_SIZE; i++)
    299 		vcache[i].vc_addr = NULL;
    300 }
    301 
    302 static void
    303 ml_init(void)
    304 {
    305 	struct ml_entry *ml;
    306 
    307 	/* Throw out the current mount list and start again. */
    308 	while ((ml = LIST_FIRST(&mount_list)) != NULL) {
    309 		LIST_REMOVE(ml, ml_entries);
    310 		free(ml);
    311 	}
    312 }
    313 
    314 
    315 static struct vnode *
    316 vc_lookup(struct vnode *vaddr)
    317 {
    318 	struct vnode *ret;
    319 	int i, oldest, match;
    320 
    321 	ret = NULL;
    322 	oldest = match = 0;
    323 	for (i = 0; i < VCACHE_SIZE || vcache[i].vc_addr == NULL; i++) {
    324 		vcache[i].vc_age++;
    325 		if (vcache[i].vc_addr == NULL)
    326 			break;
    327 		if (vcache[i].vc_age < vcache[oldest].vc_age)
    328 			oldest = i;
    329 		if (vcache[i].vc_addr == vaddr) {
    330 			vcache[i].vc_age = 0;
    331 			match = i;
    332 			ret = &vcache[i].vc_node;
    333 		}
    334 	}
    335 
    336 	/* Find an entry in the cache? */
    337 	if (ret != NULL)
    338 		return(ret);
    339 
    340 	/* Go past the end of the cache? */
    341 	if  (i >= VCACHE_SIZE)
    342 		i = oldest;
    343 
    344 	/* Read in new vnode and reset age counter. */
    345 	KREAD(vaddr, &vcache[i].vc_node, sizeof(struct vnode));
    346 	vcache[i].vc_addr = vaddr;
    347 	vcache[i].vc_age = 0;
    348 
    349 	return(&vcache[i].vc_node);
    350 }
    351 
    352 static struct mount *
    353 ml_lookup(struct mount *maddr, int size, int valid)
    354 {
    355 	struct ml_entry *ml;
    356 
    357 	for (ml = LIST_FIRST(&mount_list); ml != NULL;
    358 	    ml = LIST_NEXT(ml, ml_entries))
    359 		if (ml->ml_addr == maddr) {
    360 			ml->ml_count++;
    361 			ml->ml_size += size / 1024;
    362 			ml->ml_valid += valid / 1024;
    363 			if (ml->ml_addr == NULL)
    364 				return(NULL);
    365 			else
    366 				return(&ml->ml_mount);
    367 		}
    368 
    369 	if ((ml = malloc(sizeof(struct ml_entry))) == NULL) {
    370 		error("out of memory");
    371 		die(0);
    372 	}
    373 	LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
    374 	ml->ml_count = 1;
    375 	ml->ml_size = size / 1024;
    376 	ml->ml_valid = valid / 1024;
    377 	ml->ml_addr = maddr;
    378 	if (maddr == NULL)
    379 		return(NULL);
    380 
    381 	KREAD(maddr, &ml->ml_mount, sizeof(struct mount));
    382 	return(&ml->ml_mount);
    383 }
    384