* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Tue, May 12, 2015 at 11:10:32AM +0200, Ingo Molnar wrote: > > > > So I'd vote for Frederic's CONFIG_ISOLATION=y, mostly because this > > is a high level kernel feature, so it won't conflict with > > isolation concepts in lower level subsystems such as IOMMU > > isolation - and other higher level features like scheduler > > isolation are basically another partial implementation we want to > > merge with all this... > > But why do we need a CONFIG flag for something that has no content? > > That is, I do not see anything much; except the 'I want to stay in > userspace and kill me otherwise' flag, and I'm not sure that > warrants a CONFIG flag like this. > > Other than that, its all a combination of NOHZ_FULL and > cpusets/isolcpus and whatnot. Yes, that's what I meant: CONFIG_ISOLATION would trigger what is NO_HZ_FULL today - we could possibly even remove CONFIG_NO_HZ_FULL as an individual Kconfig option? CONFIG_ISOLATION=y would express the guarantee from the kernel that it's possible for user-space to configure itself to run undisturbed - instead of the current inconsistent set of options and facilities. A bit like CONFIG_PREEMPT_RT is more than just preemptable spinlocks, it also tries to offer various facilities and tune the defaults to turn the kernel hard-rt. Does that make sense to you? Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
