* Copyright (c) 1999 The NetBSD Foundation, Inc.

/* $NetBSD: bufcache.c,v 1.30 2020/03/02 09:50:12 mrg Exp $ */

/*-
* Copyright (c) 1999 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Simon Burge.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: bufcache.c,v 1.30 2020/03/02 09:50:12 mrg Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <sys/buf.h>
#define __EXPOSE_MOUNT
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>

#include <uvm/uvm_extern.h>

#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdbool.h>

#include <miscfs/specfs/specdev.h>

#include "systat.h"
#include "extern.h"

#define VCACHE_SIZE 50
#define PAGEINFO_ROWS 5

struct vcache {
int vc_age;
struct vnode *vc_addr;
struct vnode vc_node;
};

struct ml_entry {
u_int ml_count;
u_long ml_size;
u_long ml_valid;
struct mount *ml_addr;
LIST_ENTRY(ml_entry) ml_entries;
struct mount ml_mount;
};

static struct vcache vcache[VCACHE_SIZE];
static LIST_HEAD(mount_list, ml_entry) mount_list;

static uint64_t bufmem;
static u_int nbuf, pgwidth, kbwidth;
static struct uvmexp_sysctl uvmexp;

static void vc_init(void);
static void ml_init(void);
static struct vnode *vc_lookup(struct vnode *);
static struct mount *ml_lookup(struct mount *, int, int);
static void fetchuvmexp(void);

WINDOW *
openbufcache(void)
{

return (subwin(stdscr, -1, 0, 5, 0));
}

void
closebufcache(WINDOW *w)
{

if (w == NULL)
return;
wclear(w);
wrefresh(w);
delwin(w);
ml_init(); /* Clear out mount list */
}

void
labelbufcache(void)
{
int i;

for (i = 0; i <= PAGEINFO_ROWS; i++) {
wmove(wnd, i, 0);
wclrtoeol(wnd);
}
mvwaddstr(wnd, PAGEINFO_ROWS + 1, 0,
"File System Bufs used % kB in use % Bufsize kB % Util %");
wclrtoeol(wnd);
}

void
showbufcache(void)
{
int tbuf, i, lastrow;
double tvalid, tsize;
struct ml_entry *ml;
size_t len;
static int mib[] = { -1, 0 };

if (mib[0] == -1) {
len = __arraycount(mib);
if (sysctlnametomib("vm.bufmem", mib, &len) == -1)
error("can't get \"vm.bufmem\" mib: %s",
strerror(errno));
}
len = sizeof(bufmem);
if (sysctl(mib, 2, &bufmem, &len, NULL, 0) == -1)
error("can't get \"vm.bufmem\": %s", strerror(errno));

mvwprintw(wnd, 0, 0,
" %*d metadata buffers using %*"PRIu64" kBytes of "
"memory (%2.0f%%).",
pgwidth, nbuf, kbwidth, bufmem / 1024,
((bufmem * 100.0) + 0.5) / getpagesize() / uvmexp.npages);
wclrtoeol(wnd);
mvwprintw(wnd, 1, 0,
" %*" PRIu64 " pages for cached file data using %*"
PRIu64 " kBytes of memory (%2.0f%%).",
pgwidth, uvmexp.filepages,
kbwidth, uvmexp.filepages * getpagesize() / 1024,
(uvmexp.filepages * 100 + 0.5) / uvmexp.npages);
wclrtoeol(wnd);
mvwprintw(wnd, 2, 0,
" %*" PRIu64 " pages for executables using %*"
PRIu64 " kBytes of memory (%2.0f%%).",
pgwidth, uvmexp.execpages,
kbwidth, uvmexp.execpages * getpagesize() / 1024,
(uvmexp.execpages * 100 + 0.5) / uvmexp.npages);
wclrtoeol(wnd);
mvwprintw(wnd, 3, 0,
" %*" PRIu64 " pages for anon (non-file) data %*"
PRIu64 " kBytes of memory (%2.0f%%).",
pgwidth, uvmexp.anonpages,
kbwidth, uvmexp.anonpages * getpagesize() / 1024,
(uvmexp.anonpages * 100 + 0.5) / uvmexp.npages);
wclrtoeol(wnd);
mvwprintw(wnd, 4, 0,
" %*" PRIu64 " free pages %*"
PRIu64 " kBytes of memory (%2.0f%%).",
pgwidth, uvmexp.free,
kbwidth, uvmexp.free * getpagesize() / 1024,
(uvmexp.free * 100 + 0.5) / uvmexp.npages);
wclrtoeol(wnd);

if (nbuf == 0 || bufmem == 0) {
wclrtobot(wnd);
return;
}

tbuf = 0;
tvalid = tsize = 0;
lastrow = PAGEINFO_ROWS + 2; /* Leave room for header. */
for (i = lastrow, ml = LIST_FIRST(&mount_list); ml != NULL;
i++, ml = LIST_NEXT(ml, ml_entries)) {

int cnt = ml->ml_count;
double v = ml->ml_valid;
double s = ml->ml_size;

/* Display in window if enough room. */
if (i < getmaxy(wnd) - 2) {
mvwprintw(wnd, i, 0, "%-20.20s", ml->ml_addr == NULL ?
"NULL" : ml->ml_mount.mnt_stat.f_mntonname);
wprintw(wnd,
" %6d %3d %8ld %3.0f %8ld %3.0f %3.0f",
cnt, (100 * cnt) / nbuf,
(long)(v/1024), 100 * v / bufmem,
(long)(s/1024), 100 * s / bufmem,
100 * v / s);
wclrtoeol(wnd);
lastrow = i;
}

/* Update statistics. */
tbuf += cnt;
tvalid += v;
tsize += s;
}

wclrtobot(wnd);
mvwprintw(wnd, lastrow + 2, 0,
"%-20s %6d %3d %8ld %3.0f %8ld %3.0f %3.0f",
"Total:", tbuf, (100 * tbuf) / nbuf,
(long)(tvalid/1024), 100 * tvalid / bufmem,
(long)(tsize/1024), 100 * tsize / bufmem,
tsize != 0 ? ((100 * tvalid) / tsize) : 0);
}

int
initbufcache(void)
{
fetchuvmexp();
pgwidth = (int)(floor(log10((double)uvmexp.npages)) + 1);
kbwidth = (int)(floor(log10(uvmexp.npages * getpagesize() / 1024.0)) +
1);

return(1);
}

static void
fetchuvmexp(void)
{
int mib[2];
size_t size;

/* Re-read pages used for vnodes & executables */
size = sizeof(uvmexp);
mib[0] = CTL_VM;
mib[1] = VM_UVMEXP2;
if (sysctl(mib, 2, &uvmexp, &size, NULL, 0) < 0) {
error("can't get uvmexp: %s\n", strerror(errno));
memset(&uvmexp, 0, sizeof(uvmexp));
}
}

void
fetchbufcache(void)
{
int count;
struct buf_sysctl *bp, *buffers;
struct vnode *vn;
struct ml_entry *ml;
int mib[6];
size_t size;
int extraslop = 0;

/* Re-read pages used for vnodes & executables */
fetchuvmexp();

/* Initialise vnode cache and mount list. */
vc_init();
ml_init();

/* Get metadata buffers */
size = 0;
buffers = NULL;
mib[0] = CTL_KERN;
mib[1] = KERN_BUF;
mib[2] = KERN_BUF_ALL;
mib[3] = KERN_BUF_ALL;
mib[4] = (int)sizeof(struct buf_sysctl);
mib[5] = INT_MAX; /* we want them all */
again:
if (sysctl(mib, 6, NULL, &size, NULL, 0) < 0) {
error("can't get buffers size: %s\n", strerror(errno));
return;
}
if (size == 0)
return;

size += extraslop * sizeof(struct buf_sysctl);
buffers = malloc(size);
if (buffers == NULL) {
error("can't allocate buffers: %s\n", strerror(errno));
return;
}
if (sysctl(mib, 6, buffers, &size, NULL, 0) < 0) {
free(buffers);
if (extraslop < 1000) {
extraslop += 100;
goto again;
}
error("can't get buffers: %s\n", strerror(errno));
return;
}

nbuf = size / sizeof(struct buf_sysctl);
for (bp = buffers; bp < buffers + nbuf; bp++) {
if (UINT64TOPTR(bp->b_vp) != NULL) {
struct mount *mp;
vn = vc_lookup(UINT64TOPTR(bp->b_vp));
if (vn == NULL)
break;

mp = vn->v_mount;
/*
* References to mounted-on vnodes should be
* counted towards the mounted filesystem.
*/
if (vn->v_type == VBLK && vn->v_specnode != NULL) {
specnode_t sn;
specdev_t sd;
if (!KREAD(vn->v_specnode, &sn, sizeof(sn)))
continue;
if (!KREAD(sn.sn_dev, &sd, sizeof(sd)))
continue;
if (sd.sd_mountpoint)
mp = sd.sd_mountpoint;
}
if (mp != NULL)
(void)ml_lookup(mp, bp->b_bufsize,
bp->b_bcount);
}
}

/* simple sort - there's not that many entries */
do {
if ((ml = LIST_FIRST(&mount_list)) == NULL ||
LIST_NEXT(ml, ml_entries) == NULL)
break;

count = 0;
for (ml = LIST_FIRST(&mount_list); ml != NULL;
ml = LIST_NEXT(ml, ml_entries)) {
if (LIST_NEXT(ml, ml_entries) == NULL)
break;
if (ml->ml_count < LIST_NEXT(ml, ml_entries)->ml_count) {
ml = LIST_NEXT(ml, ml_entries);
LIST_REMOVE(ml, ml_entries);
LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
count++;
}
}
} while (count != 0);

free(buffers);
}

static void
vc_init(void)
{
int i;

/* vc_addr == NULL for unused cache entry. */
for (i = 0; i < VCACHE_SIZE; i++)
vcache[i].vc_addr = NULL;
}

static void
ml_init(void)
{
struct ml_entry *ml;

/* Throw out the current mount list and start again. */
while ((ml = LIST_FIRST(&mount_list)) != NULL) {
LIST_REMOVE(ml, ml_entries);
free(ml);
}
}

static struct vnode *
vc_lookup(struct vnode *vaddr)
{
struct vnode *ret;
size_t i, oldest;

ret = NULL;
oldest = 0;
for (i = 0; i < VCACHE_SIZE; i++) {
if (vcache[i].vc_addr == NULL)
break;
vcache[i].vc_age++;
if (vcache[i].vc_age < vcache[oldest].vc_age)
oldest = i;
if (vcache[i].vc_addr == vaddr) {
vcache[i].vc_age = 0;
ret = &vcache[i].vc_node;
}
}

/* Find an entry in the cache? */
if (ret != NULL)
return(ret);

/* Go past the end of the cache? */
if (i >= VCACHE_SIZE)
i = oldest;

/* Read in new vnode and reset age counter. */
if (KREAD(vaddr, &vcache[i].vc_node, sizeof(struct vnode)) == 0)
return NULL;
vcache[i].vc_addr = vaddr;
vcache[i].vc_age = 0;

return(&vcache[i].vc_node);
}

static struct mount *
ml_lookup(struct mount *maddr, int size, int valid)
{
struct ml_entry *ml;

for (ml = LIST_FIRST(&mount_list); ml != NULL;
ml = LIST_NEXT(ml, ml_entries))
if (ml->ml_addr == maddr) {
ml->ml_count++;
ml->ml_size += size;
ml->ml_valid += valid;
if (ml->ml_addr == NULL)
return(NULL);
else
return(&ml->ml_mount);
}

if ((ml = malloc(sizeof(struct ml_entry))) == NULL) {
error("out of memory");
die(0);
}
LIST_INSERT_HEAD(&mount_list, ml, ml_entries);
ml->ml_count = 1;
ml->ml_size = size;
ml->ml_valid = valid;
ml->ml_addr = maddr;
if (maddr == NULL)
return(NULL);

KREAD(maddr, &ml->ml_mount, sizeof(struct mount));
return(&ml->ml_mount);
}