> - VM areas are limited to 128MB. This leads to many swap-files. (I am
> not quite shure about further limitation. Does it mean that bigger
> mmaps are not possible? The swapfile limitation is definitely in the
> kernel.)
Are they???
> 1) Good support for swapping of shared pages
Aging is step 1, efficiency will have to be looked into...
> 4) implementation of the 'madvise' call, especially the MADV_DONTNEED
> parameter.
This could be done by a simple syscall whereby a process sets
the age of a specified (own) page to 0.
> The need for MADV_DONTNEED is a similar problem: no memory manager can
> know that I really don't need a part of memory any more. It will
> always try to save the memory in backing store.
> But especially transactional programs process some memory and when the
> transaction finishes there is no need to get this content again. It
> will be overwritten by the next transaction. So the program can
> advise the OS to simply discard the page instead of saving the page to
> the swapfile. This can increase the system performance a lot under low
> physical memory.
Ahh, I get it. Now, how should we implement this one?
Rik.
PLEASE, test my vhand patch and send comments/flames/code improvements
to me...
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Send Linux memory-management wishes to me: I'm currently looking
for something to hack...