Re: 2.4.8-pre7: still buffer cache problems[+2.4.9-pre3 comments]

On Thu, Aug 09, 2001 at 08:20:32PM -0400, marc heckmann wrote:

quoted

OK, there is no obvious way to do do drop-behind on
buffer cache pages, but I think we can use a quick
hack to make the system behave well under the presence
of large amounts of buffer cache pages.

What we could do is, in refill_inactive_scan(), just
moving buffer cache pages to the inactive list regardless
of page aging when there are too many buffercache pages
around in the system.

Does the patch below help you ?

well, the buffer cache still got huge and the system still swapped out like
mad, but it seemed like the buffer cache grew _slower_ and that the vm was
more fair towards other vm users. so interactivity was better but still far
from 2.2. and then it oops'ed [I don't think it was because of your patch
though..]:

I tried 2.4.8 final and it fixes the problem.... could it be the 
fs/buffer.c changes? behaviour is now like 2.2 (good in this case). if I 
have time I'll try 2.4.8-ac5 to se if it also fixes it. thanks to whoever 
is responsible for the fix.

also I tried 2.4.9-pre3 and it performs _much_ [I'd say 10 times better!]
better under high VM load specifically when filling all ram+swap. Where
2.4.8 used to thrash without making any progress what so ever [I'd have to
reset], 2.4.9-pre3 will either oom_kill (the _right_ process) or manage to
handle swap to let processes run without thrashing. this is all on PPC 
without any highmem (192Mb + 200mb swap.).


	Cheers,

	-marc

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