xsh_memstat.c

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/* xsh_memstat.c - xsh_memstat */

#include <xinu.h>
#include <stdio.h>
#include <string.h>

static  void    printMemUse(void);
static  void    printFreeList(void);

/*------------------------------------------------------------------------
 * xsh_memstat - Print statistics about memory use and dump the free list
 *------------------------------------------------------------------------
 */
shellcmd xsh_memstat(int nargs, char *args[])
{

    /* For argument '--help', emit help about the 'memstat' command */

    if (nargs == 2 && strncmp(args[1], "--help", 7) == 0) {
        printf("use: %s \n\n", args[0]);
        printf("Description:\n");
        printf("\tDisplays the current memory use and prints the\n");
        printf("\tfree list.\n");
        printf("Options:\n");
        printf("\t--help\t\tdisplay this help and exit\n");
        return 0;
    }

    /* Check for valid number of arguments */

    if (nargs > 1) {
        fprintf(stderr, "%s: too many arguments\n", args[0]);
        fprintf(stderr, "Try '%s --help' for more information\n",
                args[0]);
        return 1;
    }

    printMemUse();
    printFreeList();

    return 0;
}


/*------------------------------------------------------------------------
 * printFreeList - Walk the list of free memory blocks and print the
 *          location and size of each
 *------------------------------------------------------------------------
 */
static void printFreeList(void)
{
    struct memblk *block;

    /* Output a heading for the free list */

    printf("Free List:\n");
    printf("Block address  Length (dec)  Length (hex)\n");
    printf("-------------  ------------  ------------\n");
    
    for (block = memlist.mnext; block != NULL; block = block->mnext) {
        printf("  0x%08x    %9d     0x%08x\n", block,
            block->mlength, block->mlength);
    }
    printf("\n");
}

extern void start(void);
extern void *_end;

/*------------------------------------------------------------------------
 * printMemUse - Print statistics about memory use
 *------------------------------------------------------------------------
 */
static void printMemUse(void)
{
    int i;              /* Index into process table */
    uint32 code = 0;        /* Total Xinu code memory   */
    uint32 stack = 0;       /* Total used stack memory  */
    uint32 kheap = 0;       /* Free kernel heap memory  */
    uint32 kfree = 0;       /* Total free memory        */
    struct memblk *block;       /* Ptr to memory block      */

    /* Calculate amount of text memory */

    code = (uint32)&_end - (uint32)start;

    /* Calculate amount of allocated stack memory */
    /*  Skip the NULL process since it has a private stack */

    for (i = 1; i < NPROC; i++) {
        if (proctab[i].prstate != PR_FREE) {
            stack += (uint32)proctab[i].prstklen;
        }
    }

    /* Calculate the amount of memory on the free list */

    for (block = memlist.mnext; block != NULL; block = block->mnext) {
        kfree += block->mlength;
    }

    /* Calculate the amount of free kernel heap memory */

    kheap = kfree - stack;

    /* Output statistics on current memory use */

    printf("Current system memory statistics:\n");
    printf("---------------------------------\n");
    printf("%10d bytes (0x%08x) of Xinu code\n", code, code);
    printf("%10d bytes (0x%08x) of allocated stack space\n", stack, stack);
    printf("%10d bytes (0x%08x) of available kernel heap space\n\n", kheap, kheap);
}