mallinfo(3) - wariua/manpages-ko GitHub Wiki

#include <malloc.h>

struct mallinfo mallinfo(void);

struct mallinfo {
    int arena;     /* 비 mmap 할당 공간 (바이트) */
    int ordblks;   /* 유휴 청크 수 */
    int smblks;    /* 유휴 패스트빈 블록 수 */
    int hblks;     /* mmap 영역 수 */
    int hblkhd;    /* mmap 영역들의 할당 공간 (바이트) */
    int usmblks;   /* 총 할당 공간 최대치 (바이트) */
    int fsmblks;   /* 유휴 패스트빈 블록들의 공간 (바이트) */
    int uordblks;  /* 총 할당 공간 (바이트) */
    int fordblks;  /* 총 유휴 공간 (바이트) */
    int keepcost;  /* 최상단의 해제 가능 공간 (바이트) */
};

#include <malloc.h>
#include <stdlib.h>
#include <string.h>

static void
display_mallinfo(void)
{
    struct mallinfo mi;

    mi = mallinfo();

    printf("Total non-mmapped bytes (arena):       %d\n", mi.arena);
    printf("# of free chunks (ordblks):            %d\n", mi.ordblks);
    printf("# of free fastbin blocks (smblks):     %d\n", mi.smblks);
    printf("# of mapped regions (hblks):           %d\n", mi.hblks);
    printf("Bytes in mapped regions (hblkhd):      %d\n", mi.hblkhd);
    printf("Max. total allocated space (usmblks):  %d\n", mi.usmblks);
    printf("Free bytes held in fastbins (fsmblks): %d\n", mi.fsmblks);
    printf("Total allocated space (uordblks):      %d\n", mi.uordblks);
    printf("Total free space (fordblks):           %d\n", mi.fordblks);
    printf("Topmost releasable block (keepcost):   %d\n", mi.keepcost);
}

int
main(int argc, char *argv[])
{
#define MAX_ALLOCS 2000000
    char *alloc[MAX_ALLOCS];
    int numBlocks, j, freeBegin, freeEnd, freeStep;
    size_t blockSize;

    if (argc < 3 || strcmp(argv[1], "--help") == 0) {
        fprintf(stderr, "%s num-blocks block-size [free-step "
                "[start-free [end-free]]]\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    numBlocks = atoi(argv[1]);
    blockSize = atoi(argv[2]);
    freeStep = (argc > 3) ? atoi(argv[3]) : 1;
    freeBegin = (argc > 4) ? atoi(argv[4]) : 0;
    freeEnd = (argc > 5) ? atoi(argv[5]) : numBlocks;

    printf("============== Before allocating blocks ==============\n");
    display_mallinfo();

    for (j = 0; j < numBlocks; j++) {
        if (numBlocks >= MAX_ALLOCS) {
            fprintf(stderr, "Too many allocations\n");
            exit(EXIT_FAILURE);
        }

        alloc[j] = malloc(blockSize);
        if (alloc[j] == NULL) {
            perror("malloc");
            exit(EXIT_FAILURE);
        }
    }

    printf("\n============== After allocating blocks ==============\n");
    display_mallinfo();

    for (j = freeBegin; j < freeEnd; j += freeStep)
        free(alloc[j]);

    printf("\n============== After freeing blocks ==============\n");
    display_mallinfo();

    exit(EXIT_SUCCESS);
}