Giant-free ahc?

Daniel Eriksson daniel_k_eriksson at
Mon Oct 11 11:48:43 PDT 2004

Is anyone working on fine-grained locking for the ahc driver?

I just upgraded one of my servers from UP to SMP, and noticed that *Giant
showed up a lot when running top for processes accessing data on the SCSI
discs. It could be a GIANT lock for some other resource of course, but since
the ahc driver reports [GIANT-LOCKED] during boot, and since all the
processes were accessing data on SCSI discs I just assumed it was waiting
for a lock in the ahc driver.

Is there a simple way to figure out which resource the processes are waiting
for (without compiling in any additional debugging)?

/Daniel Eriksson

More information about the freebsd-current mailing list