On Fri, 17 Dec 2004, Sonny Rao wrote:
On Thu, Dec 16, 2004 at 04:17:53PM -0600, John Goerzen wrote:
<snip>
I noticed my problems during runs of updatedb (for locate). That
process basically reads a bunch of directories, probably stats all the
files, but never actually opens the files. (I think it runs find.)
I wonder if this has something to do with directories or inodes.
I haven't lately noticed it with updatedb runs, but I have noticed it
periodically when copying, or building ISO images or things like that.
Yes, again this sounds similar to a problem someone reported a week or
two ago, where he had a directory with 500k files and was running find
on it. The symptoms will be that kswapd is running a lot and system
responsiveness will be very poor. Also, it's certainly possible that
some of your directorys will have very few files, but what's important
is the total number of inodes in memory, not any particular directory.
You should look at the number of inodes incore at this point, and this
will give you an idea of whether this is the problem or not. Do this
by using either "slabtop" or looking at /proc/slabinfo and looking at
the number of slabs used for dentrys and inodes.
If this is indeed the problem, one stopgap measuere on > 2.6.7 kernels
is to alter the value of /proc/sys/vm/vfs_cache_pressre upwards. I
would try values with different orders of magnitude, i.e. 1000, 10000,
100000, etc. This should cause kswapd to be more aggressive in
eliminating slab objects, which means it will hold the dcache for less
time overall.
Well, I'm not really sure what I'm looking for, but I did this:
fstest -n 50 -f 10000 -s 2048
Then, in another terminal, I ran this
find . | wc -l
and from slaptop, sorted on cache size:
49396 49391 99% 0.81K 12349 4 49396K jfs_ip
46452 46228 99% 0.28K 3318 14 13272K radix_tree_node
13244 10512 79% 0.14K 473 28 1892K dentry_cache
9375 7382 78% 0.05K 125 75 500K buffer_head
At this time the disk light is (for the last 5 minutes or more now)
completely inactive (except for a very occasional blip).
Looks like I cannot kill fstest or find (kill -9 has no effect).
Both processes are in 'D+' mode.
I got fstest (I'm pretty sure mine is old) at:
http://samba.org/ftp/unpacked/junkcode/
What else can I do?
--
Jon Nelson <[EMAIL PROTECTED]>
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