On 16/11/2021 12:00, Yann Ylavic wrote:
On Wed, Nov 10, 2021 at 4:19 PM Yann Ylavic <ylavic....@gmail.com> wrote:
Otherwise I'll revert because I have no way to test it, but I think
that apr_poll_drain_wakeup_pipe() might block on Windows for the same
reason as r1894914 for platforms with poll()able pipes.
Reverted in 1.7.x, I'll leave it in trunk for now..
OK, did some digging.
First it's an abomination that 512+ threads call apr_pollset_wakeup
for the same pollset.
When I wrote that wakeup logic, 512 bytes in drain_wakeup_pipe was a
quick hack to make it work without adding 'already send wakeup for this
pollset'
Here is the original comment:
/* Although we write just one byte to the other end of the pipe
* during wakeup, multiple treads could call the wakeup.
* So simply drain out from the input side of the pipe all
* the data.
*/
So it seems it's time to make it properly :)
Basically the 'apr_file_putc(1, pollset->wakeup_pipe[1])' in
apr_pollset_wakeup should be called only if not already called
for that pollset.
pollset should have something like 'send_wakeup' member
that will be reset by apr_poll_drain_wakeup_pipe call.
The problem is how to make thread safe.
... and buf[512] in apr_poll_drain_wakeup_pipe
and then be buf[1] :)
I'll try to figure out something.
Regards
--
^TM
