Scott Long wrote:
Danny Braniss wrote:
with tags enabled, iSCSI is much faster, but it also causes a
deadlock :-(
this is what i run:
newfs -U /<iscsi device>
cd /<iscsi device>
restore rf /home/file.dump
on the same motherboard, a dual Xeon, with smp disabled all is OK
with smp enabled restore gets stuck usualy waiting on biord.
the iscsi driver shows that all requests have been done, the sniffing
shows the same(ie all request have been done).
so this leads me to think that there is some race condition that i'm not
aware of in a SMP system, where xpt_done(ccb) is called while
another process is calling biowait.
another lead is that after restore gets stuck, the system slowly gets
'stalled'.
any insight is most welcome!, i'm also stuck.
ahh, hate talking to myself :-)
grabbing Giant before calling xpt_done solved it, so the problem is
most probably in the CAM ...
danny
No, you need to grab Giant when calling xpt_done(). I even put an
assertion into CAM to make sure of that. Are you running with WITNESS
and/or INVARIANTS enabled? Those would have caught this problem.
Scott
Oops, I forgot to mention that I recently addressed this in 6-CURRENT.
Now, much of the rest of cam API still requires Giant to be held, but
xpt_done() does not. This only applies to 6-CURRENT, and I doubt that
it will be backported to 5-STABLE.
Scott
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