Cancelling aio operations on Linux

[erankor]

Hi,

An update on this - we found the problem happens when the number of aio
contexts (defaults to 32) is exceeded. When that happens nginx falls back to
using regular (synchronous) io, and for some reason this makes the kernel
not send completion notification for some pending aio requests. Increasing
worker_aio_requests to a larger value (we use 1024) solved the problem for
us.
IMHO, it would have been better if nginx would have failed the request in
this case instead of falling back to regular io. Or, at least, output some
message to the error log.

Thanks

Eran

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,269366,270973#msg-270973