Re: [PATCH] 2.2.17pre7 VM enhancement Re: I/O performance on 2.4.0-test2

["Juan J. Quintela" <quintela@fi.udc.es>]

>>>>> "andrea" == Andrea Arcangeli <andrea@suse.de> writes:

andrea> 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)

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

If you are copying in the background a cp and you don't touch your
vi/emacs/whatever pages in 2 hours (i.e. age = 0) then I think that it
is ok for that pages to be swaped out.  Notice that the cage pages
will have _initial age_  and the pages of the binaries will have an
_older_ age.

Later, Juan.

-- 
In theory, practice and theory are the same, but in practice they 
are different -- Larry McVoy
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