Messages in this thread | | | Date | Sun, 8 Mar 1998 16:32:57 -0500 (EST) | From | "Albert D. Cahalan" <> | Subject | Re: mmap() versus read() |
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>> Why does Linux page executables from their original location? >> Isn't that slower than putting it into the swapfile because >> you have to wade through the filesystem layer when you need >> to page in? Or is the penalty for writing it into the swap >> bigger than the filesystem overhead?
Linux does not need as much swap that way. It is easy to run Linux without any swap at all.
> Later versions of OS/2 have an attribute to specify that certain > executables (DLLs that are of comparable usefulness to libc) get > swapped out instead of having the code pages discarded and paged > in from file. This apparently gives good performance gains.
Advanced filesystems like ext2 provide a way to mark an executable so that the code pages won't get discarded: the sticky bit. :-) It is an ancient feature actually, and it could be useful for libc. I don't see any reason why it would have to be restricted to executables.
> I've seen reports stating that people were investigating the > possibility of making certain file systems page code to the swap > partition instead of discarding and paging in from the executable > (for CD-ROM, NFS, and floppy).
That looks like a global sticky bit.
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