On 03/20/2014 12:47 PM, Cyrill Gorcunov wrote: > On Wed, Mar 19, 2014 at 08:06:48PM +0100, David Herrmann wrote: >> memfd_create() is similar to mmap(MAP_ANON), but returns a file-descriptor >> that you can pass to mmap(). It explicitly allows sealing and >> avoids any connection to user-visible mount-points. Thus, it's not >> subject to quotas on mounted file-systems, but can be used like >> malloc()'ed memory, but with a file-descriptor to it. >> >> memfd_create() does not create a front-FD, but instead returns the raw >> shmem file, so calls like ftruncate() can be used. Also calls like fstat() >> will return proper information and mark the file as regular file. Sealing >> is explicitly supported on memfds. >> >> Compared to O_TMPFILE, it does not require a tmpfs mount-point and is not >> subject to quotas and alike. > > If I'm not mistaken in something obvious, this looks similar to /proc/pid/map_files > feature, Pavel? Thanks, Cyrill. 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. Thanks, Pavel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
