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SubjectBugs and wishes in memory management area



Well the bug is about some modules failing loading with "unable to get
DMA memory". That makes modules unreliable. Of course I don't see
why modules are apparently using GFP_ATOMIC | GFP_DMA. When loading a
module I think we can swap.
But GFP_ATOMIC allocation could be improved because we could discard
unmodified pages I think. Correct me if I am wrong.


Wishes for memory management in 2.1

First: Real swapping. When two processes are fighting for memory and
memory is tight only way to make progress is freezing one of them and
let the other run unimpeded for a few seconds.

Second: Linux does not write to swap, pages who have never been
modified like code pages. This way Linux does not lose time wring
them. But because reading from swap is faster I think when a page is
being recalled for thez upteemth time it would be wise to write it to
swap. We will get it faster next times. However it seems it would
greatly complicate the code so perhaps it is not a good idea. (Of
course this does not apply to pages we are dicarding to make a hole
for DMA).

--

Jean Francois Martinez

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