Linux-kernel mailing list archive 1998-10,: Re: 2.1.89 broken?

# Re: 2.1.89 broken?

Andrea Arcangeli (arcangeli@mbox.queen.it)
Wed, 11 Mar 1998 23:36:01 +0100 (CET)

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On Wed, 11 Mar 1998, Rik van Riel wrote:

>On Tue, 10 Mar 1998, Scott Lampert wrote:
>
>> Far be it from me to criticize ideas made by those who know
>> much more than me, but personally I don't see how transfering stuff to swap
>> immediately instead of grabbing what ram we can from the disk
>> cache first could be considered faster or preferable. As far as
>> I can see, it would be much better performance-wise to delay swapping as
>> long as there's ram to be had from the disk cache. Isn't this the main
>> reason the disk cache is dynamic in size?

I think so:

total used free shared buffers cached
Mem: 31188 30228 960 3604 704 23512
-/+ buffers/cache: 6012 25176
Swap: 52412 7084 45328

In my system there is more swap than used memory while disk cache is more
than 3 times the used memory. I don' t need such cache (maybe it was
created by a recursive grep that if I relaunch from the beginning it will
not use the cache because it needs the top of the cache while the one
present is relative to the end of the recursive grep). Due this cache
priority against process memory, every time I return in a sleeping task it
take a _while_ to wakeup from the swap. I think we should swap only
process that are sleeping for more time than in 2.1.90-pre1, and free the
cache instead. What I am tring tell is that I like to have I/O access
during a recursive grep instead of when I return to emacs. Also the
buffer memory is very low but I don' t know what does it mean.

andrea@arca:~/devel/kernel/linux$ grep pippo `find -name \*.[ch]`
andrea@arca:~/devel/kernel/linux$ free
total used free shared buffers cached
Mem: 31188 30548 640 604 520 26808
-/+ buffers/cache: 3220 27968
Swap: 52412 10628 41784

I think that removing the 10Mbyte swapped from the cache will make
performance better.

Andrea[s] Arcangeli

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