Re: performance of filesystem xattrs with Samba4

[tridge@samba.org]

Hans,

A bit more information about the slowdown between runs (and eventual
lockup) with reiser4 that I reported in my last email.

I found that a umount/mount between runs solved the problem, leading
to a fairly consistent result and no lockup. I also found that running
a simple /bin/sync between runs solved the problem.

This implies to me that it is some in-memory structure that is the
culprit. I can't see anything obvious in /proc/slabinfo, but its been
a while since I've done any serious kernel development so maybe I just
don't know what to look for.

I also tried enabling the "strict sync" option in Samba4. This makes
the 1% flush operations in the load file map to fsync() instead of a
noop. This caused reiser4 to lockup almost immediately, with the same
symptoms as the previous lockups I reported (all smbd processes stuck
in D state). No oops messages or anything unusual in dmesg.

Cheers, Tridge