view src/usr/stressfs.c @ 13:f28daf1e47c1

clang-arm
author mir3636
date Fri, 16 Feb 2018 17:44:49 +0900
parents 83c23a36980d
children
line wrap: on
line source

// Demonstrate that moving the "acquire" in iderw after the loop that
// appends to the idequeue results in a race.

// For this to work, you should also add a spin within iderw's
// idequeue traversal loop.  Adding the following demonstrated a panic
// after about 5 runs of stressfs in QEMU on a 2.1GHz CPU:
//    for (i = 0; i < 40000; i++)
//      asm volatile("");

#include "types.h"
#include "stat.h"
#include "user.h"
#include "fs.h"
#include "fcntl.h"

int
main(int argc, char *argv[])
{
    int fd, i;
    char path[] = "stressfs0";
    char data[512];
    
    printf(1, "stressfs starting\n");
    memset(data, 'a', sizeof(data));
    
    for(i = 0; i < 4; i++)
        if(fork() > 0)
            break;
    
    printf(1, "write %d\n", i);
    
    path[8] += i;
    fd = open(path, O_CREATE | O_RDWR);
    for(i = 0; i < 20; i++)
        //    printf(fd, "%d\n", i);
        write(fd, data, sizeof(data));
    close(fd);
    
    printf(1, "read\n");
    
    fd = open(path, O_RDONLY);
    for (i = 0; i < 20; i++)
        read(fd, data, sizeof(data));
    close(fd);
    
    wait();
    
    exit();
}