Re: [PATCH] 2.2.17pre7 VM enhancement Re: I/O performance on2.4.0-test2

[Andrea Arcangeli <andrea@suse.de>]

On Tue, 11 Jul 2000, Rik van Riel wrote:

>This is why LRU is wrong and we need page aging (which
>approximates both LRU and NFU).
>
>The idea is to remove those pages from memory which will
>not be used again for the longest time, regardless of in
>which 'state' they live in main memory.
>
>(and proper page aging is a good approximation to this)

It will still drop _all_ VM mappings from memory if you left "cp /dev/zero
." in background for say 2 hours. This in turn mean that during streming
I/O you'll have _much_ more than the current swapin/swapout troubles.

If I download a dozen of CD images with a gigabit ethernet I don't want
_anything_ to be unmapped from main RAM, and yes I may have 8giga of RAM
so I don't want to use O_DIRECT for the downloads.

Andrea

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