On 02/27/2016 03:04 PM, David Miller wrote:

From: Peter Hurley <redacted>
Date: Sat, 27 Feb 2016 12:29:39 -0800

quoted

Not really. softirq raised from interrupt context will always execute
on this cpu and not in ksoftirqd, unless load forces softirq loop abort.

That guarantee never was specified.

??

Neither is running network socket servers at normal priority as if they're
higher priority than softirq.

Or are you saying that by design, on a system under load, your UART
will not function properly?

Surely you don't mean that.

No, that's not what I mean.

What I mean is that bypassing the entire SOFTIRQ priority so that
sshd can process one network packet makes a mockery of the point of softirq.

This hack to workaround NET_RX looping over-and-over-and-over affects every
subsystem, not just one uart.

HI, TIMER, BLOCK; all of these are skipped: that's straight-up, a bug.

Regards,
Peter Hurley