Re: HEADS-UP: await/asleep removal imminent

[John Baldwin]

On 19-Jan-01 Poul-Henning Kamp wrote:
> In message <[EMAIL PROTECTED]>, John Baldwin writes:
>>
>>This is _not_ true.  My quad xeon test box runs a pure source tree, and has
>>not
>>had a single problem building many worlds and releases since the fix to
>>atomic_store_rel_ptr(). 
> 
> How many disks are active when you build world on that box ?

Just one.  I don't have any boxes actually with lots of disks in them. 
Details like this would be helpful though.  I'll see if I can't find someone to
rummage together a vinum stripe to build on or some such.  However, after
thinking some more, even in a preemptive kernel, Giant will protect against the
*strategy() race you brought up, because we won't get a context switch in
kernel mode that releases Giant until either we exit the kernel or we call
tsleep().  The interrupt handler will block on Giant when its thread runs, so
it won't run until the top half finishes and returns.  Does that make sense?

-- 

John Baldwin <[EMAIL PROTECTED]> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/


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