Re: madvise(2) MADV_SEQUENTIAL behavior

From: Chris Snook
Date: Thu Jul 17 2008 - 14:05:30 EST

Rik van Riel wrote:
On Thu, 17 Jul 2008 16:14:29 +1000
Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:

It might encourage user space applications to start using
FADV_SEQUENTIAL or FADV_NOREUSE more often (as it would become
worthwhile to do so), and if they do (especially cron jobs), the problem
of the slow desktop in the morning would progressively solve itself.
The slow desktop in the morning should not happen even without such a
call, because the kernel should not throw out frequently used data (even
if it is not quite so recent) in favour of streaming data.

OK, I figure it doesn't do such a good job now, which is sad,

Do you have any tests in mind that we could use to decide
whether the patch I posted Tuesday would do a decent job
at protecting frequently used data from streaming data?

1) start up a memory-hogging Java app
2) run a full-system backup

If it works well, the Java app shouldn't slow down much.

-- Chris
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