Rob van der Heij wrote:
On 2/22/07, John Summerfield <[EMAIL PROTECTED]> wrote:
The ramdisk should be able to be put, uncompressed, into a DASD all by
itself, and mounted from there. Or placed, unpacked into /boot along
with the kernel. A DASD probably is simpler, being a near drop-in
replacement for where the initrd gets mounted.
I tried to make the kernel understand that I had put the initrd
uncompressed in the NSS but it still wanted to copy the blocks from
that fixed location into fresh pages. But part of the problem
certainly is my lack of skills (and time).
If I understand it correctly, some parts of the initrd remain in use
during normal operation (some of the driver modules). So it would make
sense to share them and increase chances of keeping them in real
memory, like with the kernel.
I would expect the modules to be copied to (virtual) RAM, but if you're
using a compressed initrd then they're going to be copied twice.
I don't have any idea of what the kernel does, but I'd expect not much.
It seems to get mounted at /initrd - when that first appeared some folk
tried deleting with unfortunate results.
Probably best done by a vendor, but someone with the hardware could give
it some thought.
Can VDISK be profitably used in place of tmpfs?
Unfortunately Linux would still consider it to be disk and also cache
the files. Potentially we'd have two copies of all around, and
depending on the allocation strategy of the file system we end up also
retaining data from deleted files on VM paging space.
With tmpfs it remains in virtual memory only once, you avoid the
overhead of building channel programs and doing the I/O. "Computer
says no... "
How about
mount -o sync
which is used on (small) USB storage devices to as to reduce the harmful
effects of unplugging one without unmounting it.
--
Cheers
John
-- spambait
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