On 06-May-01 Seigo Tanimura wrote:
> As conversion of select(2) from msleep(9) to a condition variable is
> in the SMPng TODO list, I have done that task.
>
> Also, we do not have to lock a process in order to evaluate the result
> of {sel,poll}scan() and the remaining time of {select,poll}(2). It
> should be enough to do those pieces of work first, followed by locking
> a process and wait for a condition variable or selwakeup().
You need the lock when clearing the bit in p_flag. That is why the proc locks
are there, so all those proc locks need to stay. When you clear a bit, you are
writing all the bits, so you need to ensure that you can atomically
read/modify/write all the bits in p_flag, hence the need for the proc lock.
Please back out the changes to not lock the process around the p_flag change.
The rest of the patch looks ok, though I'd like to review the updated version
before it is committed. Thanks.
> Those changes are in the patch at:
>
> http://people.FreeBSD.org/~tanimura/patches/selectopt.diff
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