/*      $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);
}