Re: Why linux memory management isn't clever, always hold large memroy?
On Sun, Oct 08, 2006 at 11:51:46AM +0800, bowen wrote:
> (Why mysql or system do not automatic free some of
> the loaded data from memory, Just use a little swap space to sawp out
> a little memory).
> shell# free
> total used free shared buffers cached
> Mem: 516488 459376 57112 0 8 420152
> -/+ buffers/cache: 39216 477272
> Swap: 1023992 80 1023912
The output of free here shows that only a little swap space is being used.
Only 80k, to be exact.
It also shows that almost all of the RAM in use is being used for
buffers and cache, i.e., it's being used to hold data that the kernel
thinks might be needed in the near future. If the kernel is right, it
avoids that nasty waiting for I/O that slows everything down. If the
kernel is wrong, the cache can be freed more-or-less instantly to make
it available for whatever else needs the memory instead. Overall, this
improves performance significantly. It's not the problem you think it is.
--
I would rather be exposed to the inconvenience attending too much Liberty
than those attending too small degree of it.
- Thomas Jefferson
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