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#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <error.h>
#include <stdio.h>
int exiterr(const char *s)
{
perror(s);
exit(-1);
}
int main(int argc, char *argv[])
{
int i, j;
int pages;
int PAGESIZE;
int quiet = 0;
int verbose = 0;
int fd;
struct stat st;
void *file = NULL;
unsigned char *pageinfo = NULL;
PAGESIZE = getpagesize();
if(argc > 1) {
if(!strcmp("-v", argv[1]))
verbose = 1;
else if(!strcmp("-q", argv[1]))
quiet = 1;
} else {
fprintf(stderr, "usage: %s [-qv] <file> "
"-- print out cache statistics\n", argv[0]);
fprintf(stderr, "\t-v\tprint verbose cache map\n");
fprintf(stderr, "\t-q\texit code tells if file is fully cached\n");
exit(1);
}
if(quiet || verbose)
argv++;
fd = open(argv[1], O_RDONLY);
if(fd == -1)
exiterr("open");
if(fstat(fd, &st) == -1)
exiterr("fstat");
if(!S_ISREG(st.st_mode)) {
fprintf(stderr, "%s: S_ISREG: not a regular file", argv[1]);
return EXIT_FAILURE;
}
if(st.st_size == 0) {
fprintf(stderr, "%s: file size is 0!\n", argv[1]);
return EXIT_FAILURE;
}
pages = (st.st_size + PAGESIZE - 1) / PAGESIZE;
pageinfo = calloc(sizeof(*pageinfo), pages);
if(!pageinfo)
exiterr("calloc");
file = mmap(NULL, st.st_size, PROT_NONE, MAP_SHARED, fd, 0);
if(file == MAP_FAILED)
exiterr("mmap");
if(mincore(file, st.st_size, pageinfo) == -1)
exiterr("mincore");
i = j = 0;
while(i < pages)
if(pageinfo[i++] & 1)
j++;
if(quiet) {
if(j == i)
return EXIT_SUCCESS;
return EXIT_FAILURE;
}
printf("pages in cache: %d/%d (%.1f%%) [filesize=%.1fK, "
"pagesize=%dK]\n", j, i, 100.0 * j / i,
1.0 * st.st_size / 1024, PAGESIZE / 1024);
#define PAGES_PER_LINE 32
if(verbose) {
printf("\ncache map:\n");
for(i = 0; i <= (pages - 1) / PAGES_PER_LINE; i++) {
printf("%6d: |", i * PAGES_PER_LINE);
for(j = 0; j < PAGES_PER_LINE; j++) {
if(i * PAGES_PER_LINE + j == pages)
break;
printf("%c|",
pageinfo[i * PAGES_PER_LINE + j] & 1 ? 'x' : ' ');
}
printf("\n");
}
}
munmap(file, st.st_size);
return EXIT_SUCCESS;
}
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