Gavin Lambert <[EMAIL PROTECTED]> wrote:

> As far as I was aware, that's not true.  Regardless of filesystem (ramfs or
> other), if XIP isn't enabled then an *extra* copy of the executable will get
> loaded into RAM when it's run.

You have to have a guarantee that someone won't attempt to modify the file
under you.  I suppose the ETXTBSY checks ought to deal with that.

Currently, if you try to make a shared mmap of a contiguous set of pages in a
ramfs file, it will work as expected and map the ramfs's backing store
directly, so I suppose there's no reason the same shouldn't be possible for
shareable read-only/executable mappings.

The main problem is that the region that you want to map for execution *must*
be contiguous.  ramfs doesn't currently guarantee that unless you truncate the
file before filling it, but since the initramfs packer is in the kernel, that
oughtn't to be a problem.

I'll have a look.

David
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