On 11/3/10 10:52 AM, Julian Elischer wrote:
On 11/3/10 10:17 AM, John Baldwin wrote:
On Wednesday, November 03, 2010 1:04:13 pm m...@freebsd.org wrote:
So a MTX_DEF is okay in that environment?
Yes. In fact, the reason to have threads for interrupt handlers is
to allow
interrupt handlers to use non-spin locks that block when the lock
is held.
MTX_SPIN locks are generally not needed in device drivers. The
only reason a
driver would use one is if it used a filter handler which does not
run in a
threaded context.
oops
a line got deleted I think..
It should be noted that in the case where you really just want to
spin a few
instructions because some other thread is accessing a structure you
want,
... then the BTX_DEF code will spin for a short while before ...
descheduling you. so you don't always incur the scheduling overhead.
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