Messages in this thread | | | Subject | Re: DAX can not work on virtual nvdimm device | From | Xiao Guangrong <> | Date | Wed, 31 Aug 2016 16:44:47 +0800 |
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On 08/31/2016 01:09 AM, Dan Williams wrote:
> > Can you post your exact reproduction steps? This test is not failing for me. >
Sure.
1. make the guest kernel based on your tree, the top commit is 10d7902fa0e82b (dax: unmap/truncate on device shutdown) and the config file can be found in this thread.
2. add guest kernel command line: memmap=6G!10G
3: start the guest: x86_64-softmmu/qemu-system-x86_64 -machine pc,nvdimm --enable-kvm \ -smp 16 -m 32G,maxmem=100G,slots=100 /other/VMs/centos6.img -monitor stdio
4: in guest: mkfs.ext4 /dev/pmem0 mount -o dax /dev/pmem0 /mnt/pmem/ echo > /mnt/pmem/xxx ./mmap /mnt/pmem/xxx ./read /mnt/pmem/xxx
The source code of mmap and read has been attached in this mail.
Hopefully, you can detect the error triggered by read test.
Thanks! #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h>
int main(int argc, char *argv[]) { char *filename;
if (argc < 2) { printf("arg: filename.\n"); return -1; }
filename = argv[1]; printf("test on %s.\n", filename);
int fd = open(filename, O_RDWR);
if (fd < 0) { perror("open"); return -1; }
int count = 0;
while (1) { ssize_t ret; char buf;
ret = read(fd, &buf, sizeof(buf)); if (ret < 0) { perror("READ"); return -1; }
if (ret == 0) break; if (ret != sizeof(buf)) { printf("Count %x Ret %lx sizeof(buf) %lx.\n", count, ret, sizeof(buf)); return -1; }
count++; printf("%c", buf); }
printf("\n Good Read.\n"); return 0; } #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <fcntl.h> #include <unistd.h>
static void write_test(char *buf, int size) { int i;
printf("Try to write %p for %x size.\n", buf, size); for (i = 0; i < size; i++) buf[i] = (char)(i & 0xFF); printf("Write Done.\n"); }
static void read_test(char *buf, int size) { int i;
printf("Try to read %p for %x size.\n", buf, size); for (i = 0; i < size; i++) if (buf[i] != (char)(i & 0xFF)) { printf("Read Check failed.\n"); printf("Index %x, %c expect %x.\n", i, buf[i], i & 0xFF); exit(-1); } printf("Read Done.\n"); }
static void fread_test(int fd, int size) { char buf; int i;
i = lseek(fd, 0, SEEK_END); printf("End: %x.\n", i);
i = lseek(fd, 0, SEEK_SET); if (i != 0) { perror("seek"); exit(-1); }
printf("Try to fread fd=%d size %x sizeof(buf) %ld.\n", fd, size, sizeof(buf));
for (i = 0; i < size; i++) { int ret;
ret = read(fd, &buf, sizeof(buf)); if (ret != sizeof(buf)) { printf("Read failed, offset %x, ret %d ftell %ld.\n", i, ret, lseek(fd, 0, SEEK_CUR)); perror("read"); exit(-1); } if (buf != (char)(i & 0xFF)) { printf("Read Check failed.\n"); printf("Index %x, %c expect %x.\n", i, buf, i & 0xFF); exit (-1); } }
printf("Fread Done.\n"); }
int main(int argc, char *argv[]) { char *filename; char *buf; int fd;
if (argc < 2) { printf("arg: filename.\n"); return -1; }
filename = argv[1]; printf("mmap test on %s.\n", filename);
fd = open(filename, O_RDWR); if (fd < 0) { perror("open"); return -1; }
if (lseek(fd, 0x1000, SEEK_SET) != 0x1000) { perror("seek"); return -1; }
if (ftruncate(fd, 0x1000) != 0) { perror("ftruncate"); return -1; }
// return 0;
buf = mmap(NULL, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (buf == MAP_FAILED) { perror("mmap"); return -1; }
write_test(buf, 0x1000); read_test(buf, 0x1000); msync(buf, 0x1000, MS_SYNC); fread_test(fd, 0x1000);
close(fd);
return 0; }
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