fillPacket was incorrectly setting the buffer sizes and
causing large packets to be egressed incorrectly resulting
in packet drops when the MTU was > buffer size.
PiperOrigin-RevId: 420178122
When transmitting packets we only need to notify if the peer is not
already processing packets. sharedData region is used to enable/disable
notifications and the peer will disable notifications when its actively
processing packets and enable notifications just before it goes to
sleep waiting on packets. This allows more efficient transmit as the
sharedmem endpoint does not need to notify on eventFD and incur an
expensive host systemcall when the peer is already awake.
PiperOrigin-RevId: 406018843
The same create/write/read pattern is copied around several places. It's easier
to understand in a package with names and comments, and we can reuse the smart
blocking code in package rawfile.
PiperOrigin-RevId: 401647108