Hi On Thu, Mar 20, 2014 at 10:01 AM, Pavel Emelyanov <xemul@xxxxxxxxxxxxx> wrote: > On 03/20/2014 12:47 PM, Cyrill Gorcunov wrote: >> If I'm not mistaken in something obvious, this looks similar to /proc/pid/map_files >> feature, Pavel? > > It is, but the map_files will work "in the opposite direction" :) In the memfd > case one first gets an FD, then mmap()s it; in the /proc/pis/map_files case one > should first mmap() a region, then open it via /proc/self/map_files. > > But I don't know whether this matters. Yes, you can replace memfd_create() so far with: p = mmap(NULL, size, ..., MAP_ANON | MAP_SHARED, -1, 0); sprintf(path, "/proc/self/map_files/%lx-%lx", p, p + size); fd = open(path, O_RDWR); However, map_files is only enabled with CONFIG_CHECKPOINT_RESTORE, the /proc/pid/map_files/ directory is root-only (at least I get EPERM if non-root), it doesn't provide the "name" argument which is very handy for debugging, it doesn't explicitly support sealing (it requires MAP_ANON to be backed by shmem) and it's a very weird API for something this simple. Thanks David -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>