/*
 * BUFQUEUES.C
 *
 * cc -I/usr/src/sys bufqueues.c -o /usr/local/bin/bufqueues -lkvm
 *
 * bufqueues
 *
 * Output buf(9) queues usages
 *
 * Copyright (c) 2015 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * by Antonio Huete Jimenez <tuxillo@quantumachine.net>
 *
 * 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.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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.
 */

#define _KERNEL_STRUCTURES_
#include <sys/param.h>
#include <sys/user.h>
#include <sys/buf.h>
#include <sys/bio.h>
#include <sys/queue.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <fcntl.h>
#include <kvm.h>
#include <nlist.h>
#include <getopt.h>
#include <math.h>

struct nlist Nl[] = {
    { "_bufpcpu" },
    { "_ncpus" },
    { "_nbuf" },
    { NULL }
};

TAILQ_HEAD(bqueues, buf);

/*
 * Buffer queues.
 */
enum bufq_type {
        BQUEUE_NONE,    /* not on any queue */
        BQUEUE_LOCKED,  /* locked buffers */
        BQUEUE_CLEAN,   /* non-B_DELWRI buffers */
        BQUEUE_DIRTY,   /* B_DELWRI buffers */
        BQUEUE_DIRTY_HW,   /* B_DELWRI buffers - heavy weight */
        BQUEUE_EMPTYKVA, /* empty buffer headers with KVA assignment */
        BQUEUE_EMPTY,    /* empty buffer headers */

        BUFFER_QUEUES /* number of buffer queues */
};

struct bufpcpu {
        struct spinlock spin;
        struct bqueues bufqueues[BUFFER_QUEUES];
} __cachealign;

int verboseopt;

static int kkread(kvm_t *kd, u_long addr, void *buf, size_t nbytes, int out);
static void scan_queues(kvm_t *kd, int cpu, struct bufpcpu *bqp);
static void loaddelay(struct timespec *ts, const char *arg);

static const char *q2s(int queue);

/* Globals */
int qcounter[BUFFER_QUEUES];
int failcount;
int totalcount;
int nbuf;

int
main(int ac, char **av)
{
    const char *corefile = NULL;
    const char *sysfile = NULL;
    struct bufpcpu bpcpu;
    struct timespec delay = { 1, 0 };
    kvm_t *kd;
    int count;
    int ncpus;
    int ch;
    int cpu;

    while ((ch = getopt(ac, av, "M:N:v")) != -1) {
        switch(ch) {
        case 'v':
            ++verboseopt;
            break;
        case 'M':
            corefile = optarg;
            break;
        case 'N':
            sysfile = optarg;
            break;
        default:
            fprintf(stderr, "%s [-M core] [-N system]\n", av[0]);
            exit(1);
        }
    }
    ac -= optind;
    av += optind;

    if ((kd = kvm_open(sysfile, corefile, NULL, O_RDONLY, "kvm:")) == NULL) {
        perror("kvm_open");
        exit(1);
    }
    if (kvm_nlist(kd, Nl) != 0) {
        perror("kvm_nlist");
        exit(1);
    }

    if (ac > 0)
            loaddelay(&delay, av[0]);

    kkread(kd, Nl[1].n_value, &ncpus, sizeof(ncpus), 1);
    kkread(kd, Nl[2].n_value, &nbuf, sizeof(nbuf), 1);

    for (count = 0; ; ++count) {
            for (cpu = 0; cpu < ncpus; cpu++) {
                    kkread(kd, Nl[0].n_value + cpu * sizeof(struct bufpcpu),
                        &bpcpu, sizeof(struct bufpcpu), 1);
                    scan_queues(kd, cpu, &bpcpu);
            }

            if (count && !verboseopt) {
                    if ((count & 15) == 1)
                            printf("  NONE  LOCKED  CLEAN  DIRTY  "
                                "DIRTY_HW  EMPTYKVA  EMPTY  OFF-QUEUE KVMFAIL\n");
                    printf("%6d %7d %6d %6d %9d %9d %6d %10d %7d\n",
                        qcounter[0], qcounter[1], qcounter[2],
                        qcounter[3], qcounter[4], qcounter[5],
                        qcounter[6], (nbuf - totalcount), failcount);
            }

            /* If in verbose mode only output detailed bufs info once */
            if (verboseopt)
                    break;
            nanosleep(&delay, NULL);
            bzero(&qcounter, sizeof(qcounter));
            totalcount = 0;
            failcount = 0;
    }
    return(0);
}

static const char *q2s(int queue)
{
        switch(queue) {
        case BQUEUE_NONE:
                return "NONE";
        case BQUEUE_LOCKED:
                return "LOCKED";
        case BQUEUE_CLEAN:
                return "CLEAN";
        case BQUEUE_DIRTY:
                return "DIRTY";
        case BQUEUE_DIRTY_HW:
                return "DIRTY_HW";
        case BQUEUE_EMPTYKVA:
                return "EMPTYKVA";
        case BQUEUE_EMPTY:
                return "EMPTY";
        default:
                return "INVALID";
        }
}

void
scan_queues(kvm_t *kd, int cpu, struct bufpcpu *bqp)
{
        struct buf b, *tmp;
        int q;

        for (q = 0; q < BUFFER_QUEUES; q++) {
                if (bqp->bufqueues[q].tqh_first == NULL)
                        continue;
                kkread(kd, (u_long)bqp->bufqueues[q].tqh_first, &b, sizeof(b), 1);
                tmp = bqp->bufqueues[q].tqh_first;
                if (tmp != NULL)
                        qcounter[q]++;
                while (tmp != NULL) {
                        if (verboseopt)
                                printf("cpu=%d queue=%8s buf=%p", cpu, q2s(q), tmp);
                        tmp = b.b_freelist.tqe_next;
                        if (kkread(kd, (u_long)tmp, &b, sizeof(b), 0) == -1) {
                                if (verboseopt)
                                        printf(" [F] ");
                                failcount++;
                        }
                        if (verboseopt)
                                printf("\n");
                        qcounter[q]++;
                        totalcount++;   /* All scanned bufs */
                }
        }
}

/*
 * Convert a delay string (e.g. "0.1") into a timespec.
 */
static
void
loaddelay(struct timespec *ts, const char *arg)
{
        double d;

        d = strtod(arg, NULL);
        if (d < 0.001)
                d = 0.001;
        ts->tv_sec = (int)d;
        ts->tv_nsec = (int)(modf(d, &d) * 1000000000.0);
}

static int
kkread(kvm_t *kd, u_long addr, void *buf, size_t nbytes, int out)
{
    if (kvm_read(kd, addr, buf, nbytes) != nbytes) {
            if (out) {
                    perror("kvm_read");
                    exit(1);
            }
            return -1;
    }
    return 0;
}