> On Jan 21, 2020, at 11:15 AM, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: > > On Tue, Jan 21, 2020 at 09:37:13AM -0500, Qian Cai wrote: >> >> >>> On Jan 21, 2020, at 9:19 AM, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: >>> >>> One approach would be to boot with rcupdate.rcu_cpu_stall_timeout=300, >>> which would allow more time. >> >> It works for me if once that warning triggered, give a bit information about adjusting the parameter when debugging options are on to suppress the warning due to expected long boot. > > Indeed. 300 seconds as shown above is currently the maximum, but > please let me know if it needs to be increased. This module parameter > is writable after boot via sysfs, so maybe that could be part of the > workaround. > >>> Longer term, I could suppress this warning during boot when >>> CONFIG_EFI_PGT_DUMP=y, but that sounds quite specific. Alternatively, >>> I could provide a Kconfig option that suppressed this during boot >>> that was selected by whatever long-running boot-time Kconfig option >>> needed it. Yet another approach would be for long-running operations >>> like efi_dump_pagetable() to suppress stalls on entry and re-enable them >>> upon exit. >>> >>> Thoughts? >> >> None of the options sounds particularly better for me because there could come up with other options may trigger this, memtest comes in mind, for example. Then, it is a bit of pain to maintain of unknown. > > I was afraid of that. ;-) > > Could you please send me the full dmesg up to that point? No promises, > but it might well be that I can make some broad-spectrum adjustment > within RCU. Only one way to find out… https://cailca.github.io/files/dmesg.txt
