On 7/25/07, Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:
I'm not saying that we can't try to tackle that problem, but first of
all you have a really nice narrow problem where updatedb seems to be
causing the kernel to completely do the wrong thing. So we start on
that.
updatedb isn't the only problem, its just an obvious one. I like the
idea of looking into the vfs for this and other one-shot applications
(rather than looking at updatedb itself specifically)
Many modern applications have a lot of open file handles. For
example, I just fired up my usual audio player and sys/fs/file-nr
showed another 600 open files (funnily enough, I have roughly that
many audio files :) I'm not exactly sure what happens when this one
gets swapped out for whatever reason (firefox/java/vmware/etc chews
ram, updatedb, whatever) but I'm fairly confident what happens between
kswapd and the vfs and whatever else we're caching is not optimal come
time for this process to context-switch back in. We're not running a
highly-optimised number-crunching scientific app on desktops, we're
running a full herd of poorly-coded hogs simultaneously through
smaller pens.