cvs commit: src/sys/kern subr_power.c
bde at zeta.org.au
Thu Nov 10 00:14:45 PST 2005
On Wed, 9 Nov 2005, Scott Long wrote:
> Bruce Evans wrote:
>> Er, SWIs are interrupts too. Trying to sleep in a SWI handler should
>> cause the same message. This commit uses the general taskqueue SWI
>> handler. taskqueue(9) implicitly says that only the taskqueue thread
>> handler can sleep (it gives malloc(M_WAITOK) as an example of something
>> that can only be done in thread context).
Please trim quotes when replying.
> You're right, but sleeping in SWI's has never been enforced. CAM relies on
> it, for better or worse, and until that's fixed it's pointless to
> start enforcing it.
CAM at least shoots only itself in the foot if its SWIs block. The
taskqueue SWIs are shared, so sleeping in them is like sleeping in a
timeout ISR (not quite as bad, since SWI_TQ* > SWI_CLOCK). Blocking
on Giant to enter a taskqueue SWISR would be like blocking on Giant
to enter a timeout ISR except it is handled better by having a
separate ISR for cases that need Giant.
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