core: fix priority ordering in notify-handling #1707
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Currently, we dispatch NOTIFY messages in a tight loop. Regardless how much data is incoming, we always dispatch everything that is queued. This, however, completely breaks priority event-handling of sd-event. When dispatching one NOTIFY event, another completely different event might fire, or might be queued by the NOTIFY handling. However, this event will not get dispatched until all other further NOTIFY messages are handled. Those might even arrive _after_ the other event fired, and as such completely break priority ordering of sd-event (which several code paths rely on). Break this by never dispatching multiple messages. Just return after each message that was read and let sd-event handle everything else. (The patch looks scarier that it is. It basically just drops the for(;;) loop and re-indents the loop-content.)
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patch lgtm. ready to merge if semaphore agrees |
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fuck, pressed the wrong button. sorry |
core: fix priority ordering in notify-handling
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FTR: it does not fix #1505 |
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Well, I guess github was just too clever here and interpreted "whether it fixes ..." in the PR incorrectly. |
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If a similar logic is also be true for manager_dispatch_sigchld. Seems here also be too much. It takes 3.2s and which might be critical for hardware watchdog? [ 42.564130] systemd[1]: 'manager-signal' here |
Currently, we dispatch NOTIFY messages in a tight loop. Regardless how
much data is incoming, we always dispatch everything that is queued.
This, however, completely breaks priority event-handling of sd-event.
When dispatching one NOTIFY event, another completely different event
might fire, or might be queued by the NOTIFY handling. However, this
event will not get dispatched until all other further NOTIFY messages are
handled. Those might even arrive after the other event fired, and as
such completely break priority ordering of sd-event (which several code
paths rely on).
Break this by never dispatching multiple messages. Just return after each
message that was read and let sd-event handle everything else.
(The patch looks scarier that it is. It basically just drops the for(;;)
loop and re-indents the loop-content.)
Maybe related to #1505. Please test! Regardless whether it fixes #1505, this looks like something we should merge.