Messages in this thread | | | Date | Sun, 24 May 1998 15:19:59 +1000 | From | Richard Gooch <> | Subject | Re: /tmp in swap space |
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Larry McVoy writes: > : Well, I can give you a real-world example. Because I haven't yet found > : an OS which has useful mmapping semantics for /dev/zero (namely that I > : can open /dev/zero and pass a FD to another process and both processes > : can mmap() the FD and share data via the mmapped region), I end up > : creating a tmpfile in /tmp for mmapping purposes. Under Linux, this is > : at least 16 MBytes (because under 16 MBytes I can use ordinary SysV > : SHM). This tmpfile doesn't need to be saved to disc (not when you have > : gobs of RAM). > : So here is a real case where large files with a moderate lifetime (at > : least a few minutes) are created in /tmp. > > I agree with you that it would be nice to be able to share anonymous > memory between processes (which you can do with clone but that's not an > answer for unrelated processes).
That's right. And in my situation, I don't even have a parent-child relationship between the two processes.
> However, we were discussing TMPFS vs EXT2FS performance. Do you have > any reason to believe that creating a mapping in TMPFS is any faster > than one in EXT2FS?
Not really. I was just pointing out a real-world situation. One thing to consider may be that while many systems will configure 128 MBytes of swap, they might not allocate large /tmp partitions. But then, a small /tmp is not a justification for adding tmpfs to the kernel :-)
Regards,
Richard....
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