xv6

port of xv6 to x86-64
git clone http://frotz.net/git/xv6.git
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stressfs.c (1030B)


      1 // Demonstrate that moving the "acquire" in iderw after the loop that
      2 // appends to the idequeue results in a race.
      3 
      4 // For this to work, you should also add a spin within iderw's
      5 // idequeue traversal loop.  Adding the following demonstrated a panic
      6 // after about 5 runs of stressfs in QEMU on a 2.1GHz CPU:
      7 //    for (i = 0; i < 40000; i++)
      8 //      asm volatile("");
      9 
     10 #include "types.h"
     11 #include "stat.h"
     12 #include "user.h"
     13 #include "fs.h"
     14 #include "fcntl.h"
     15 
     16 int
     17 main(int argc, char *argv[])
     18 {
     19   int fd, i;
     20   char path[] = "stressfs0";
     21   char data[512];
     22 
     23   printf(1, "stressfs starting\n");
     24   memset(data, 'a', sizeof(data));
     25 
     26   for(i = 0; i < 4; i++)
     27     if(fork() > 0)
     28       break;
     29 
     30   printf(1, "write %d\n", i);
     31 
     32   path[8] += i;
     33   fd = open(path, O_CREATE | O_RDWR);
     34   for(i = 0; i < 20; i++)
     35 //    printf(fd, "%d\n", i);
     36     write(fd, data, sizeof(data));
     37   close(fd);
     38 
     39   printf(1, "read\n");
     40 
     41   fd = open(path, O_RDONLY);
     42   for (i = 0; i < 20; i++)
     43     read(fd, data, sizeof(data));
     44   close(fd);
     45 
     46   wait();
     47   
     48   exit();
     49 }