Programming Persistent Memory by Steve Scargall

Author:Steve Scargall
Language: eng
Format: epub, pdf
ISBN: 9781484249321
Publisher: Apress

Nonpersistent Stores

Nonpersistent stores refer to data written to persistent memory but not flushed explicitly. It is understood that if the program writes to persistent memory, it wishes for those writes to be persistent. If the program ends without explicitly flushing writes, there is an open possibility for data corruption. When a program exits gracefully, all the pending writes in the CPU caches are flushed automatically. However, if the program were to crash unexpectedly, writes still residing in the CPU caches could be lost.

Consider the code in Listing 12-7 that writes data to a persistent memory device mounted to /mnt/pmem without flushing the data. 32 #include <stdio.h>

33 #include <sys/mman.h>

34 #include <fcntl.h>

35

36 int main(int argc, char *argv[]) {

37 int fd, *data;

38 fd = open("/mnt/pmem/file", O_CREAT|O_RDWR, 0666);

39 posix_fallocate(fd, 0, sizeof(int));

40 data = (int *) mmap(NULL, sizeof(int), PROT_READ |

41 PROT_WRITE, MAP_SHARED_VALIDATE |

42 MAP_SYNC, fd, 0);

43 *data = 1234;

44 munmap(data, sizeof(int));

45 return 0;

46 }

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.