On Tue, Jun 20, 2023 at 09:27:48PM +0200, Uwe Kleine-König wrote: > Hello Greg, > > On Tue, Jun 20, 2023 at 04:59:18PM +0200, Greg Kroah-Hartman wrote: > > On Tue, Jun 20, 2023 at 04:47:10PM +0200, Linux regression tracking (Thorsten Leemhuis) wrote: > > > On 24.05.23 15:07, Stefan Wahren wrote: > > > > > > > > Am 23.05.23 um 21:44 schrieb Sergey Organov: > > > >> "Linux regression tracking (Thorsten Leemhuis)" > > > >> <regressions@xxxxxxxxxxxxx> writes: > > > >> > > > >> Solving this would need to identify the cause of interrupts being > > > >> disabled for prolonged times, and nobody volunteered to investigate this > > > >> further. One suspect, the Linux serial console, has been likely excluded > > > >> already though, as not actually being in use for printk() output. > > > >> > > > > > > > > I don't think that we can exclude the serial console as a whole, i never > > > > made such a observation. But at least we can exclude kernel logging on > > > > the debug UART. > > > > > > Stefan, just wondering: was this ever addressed upstream? I assume it's > > > not, just wanted to be sure. > > > > > > I'm a bit unsure what to do with this and consider asking Greg for > > > advice, as he applied the patch. On one hand it's *IMHO* clearly a > > > regression (but for the record, some people involved in the discussion > > > claim it's not). OTOH the culprit was applied more than a year ago now, > > > so reverting it might cause more trouble than it's worth at this point, > > > as that could lead to regressions for other users. > > > > I'll be glad to revert this, but for some reason I thought that someone > > was working on a "real fix" here. Stefan, is that not the case? > > Sergey Organov already said something similar, but not very explicit: > With the current understanding reverting said commit is wrong. It is > expected that the commit increases irq latency for imx-serial a bit for > the benefit of less interrupts and so serves the overall system > performance. That this poses a problem only means that on the reporter's > machine there is already an issue that results in a longer period with > disabled irqs. While reverting the imx-serial commit would (maybe) solve > that, the actual problem is the other issue that disables preemption for > a longer timespan. > > So TL;DR: Please don't revert the imx-serial patch. Ok, will leave this alone, it shouldn't be marked as a regression. greg k-h
