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d15121be74
This reverts the following commits:4cd13c21b2("softirq: Let ksoftirqd do its job")3c53776e29("Mark HI and TASKLET softirq synchronous")1342d8080f("softirq: Don't skip softirq execution when softirq thread is parking") in a single change to avoid known bad intermediate states introduced by a patch series reverting them individually. Due to the mentioned commit, when the ksoftirqd threads take charge of softirq processing, the system can experience high latencies. In the past a few workarounds have been implemented for specific side-effects of the initial ksoftirqd enforcement commit: commit1ff688209e("watchdog: core: make sure the watchdog_worker is not deferred") commit8d5755b3f7("watchdog: softdog: fire watchdog even if softirqs do not get to run") commit217f697436("net: busy-poll: allow preemption in sk_busy_loop()") commit3c53776e29("Mark HI and TASKLET softirq synchronous") But the latency problem still exists in real-life workloads, see the link below. The reverted commit intended to solve a live-lock scenario that can now be addressed with the NAPI threaded mode, introduced with commit29863d41bb("net: implement threaded-able napi poll loop support"), which is nowadays in a pretty stable status. While a complete solution to put softirq processing under nice resource control would be preferable, that has proven to be a very hard task. In the short term, remove the main pain point, and also simplify a bit the current softirq implementation. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: netdev@vger.kernel.org Link: https://lore.kernel.org/netdev/305d7742212cbe98621b16be782b0562f1012cb6.camel@redhat.com Link: https://lore.kernel.org/r/57e66b364f1b6f09c9bc0316742c3b14f4ce83bd.1683526542.git.pabeni@redhat.com