* Chris Metcalf <cmetcalf@xxxxxxxxxxxx> wrote: > On 03/03/2016 01:34 PM, Andi Kleen wrote: > >Chris Metcalf <cmetcalf@xxxxxxxxxx> writes: > >>+config TASK_ISOLATION_ALL > >>+ bool "Provide task isolation on all CPUs by default (except CPU 0)" > >>+ depends on TASK_ISOLATION > >>+ help > >>+ If the user doesn't pass the task_isolation boot option to > >>+ define the range of task isolation CPUs, consider that all > >>+ CPUs in the system are task isolation by default. > >>+ Note the boot CPU will still be kept outside the range to > >>+ handle timekeeping duty, etc. > >That seems like a very dangerous Kconfig option. > >"CONFIG_BREAK_EVERYTHING" > >If someone sets that by default they will have a lot of trouble. > > > >I wouldn't add that, make it a run time option only. > > So you were thinking, allow a special boot syntax "task_isolation=all", > which puts all the cores into task isolation mode except the boot core? > > My original argument was that it was so parallel to the existing > CONFIG_NO_HZ_FULL_ALL option that it just made sense to do it, > and some testers complained about having to specify the precise > cpu range, so this seemed like an easy fix. Yes, it's absolutely legitimate to offer boot options as Kconfig options as well - in fact that will get things like randconfig bootups stumble upon them and do some free testing for you. Just ignore Andi's nonsensical objection. One day we'll have a unified boot parameter/Kconfig/sysctl mechanism, so that it will be possible to say things like this on the boot command line: CONFIG_NO_HZ_FULL_ALL=y ... which will eliminate quite a bit of the current schizm between Kconfig and boot time parameters. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
