On Tue, Feb 23, 2021 at 10:56:46AM +0000, Vincenzo Frascino wrote: > On 2/22/21 5:58 PM, Catalin Marinas wrote: > > We'll still have an issue with dynamically switching the async/sync mode > > at run-time. Luckily kasan doesn't do this now. The problem is that > > until the last CPU have been switched from async to sync, we can't > > toggle the static label. When switching from sync to async, we need > > to do it on the first CPU being switched. > > I totally agree on this point. In the case of runtime switching we might need > the rethink completely the strategy and depends a lot on what we want to allow > and what not. For the kernel I imagine we will need to expose something in > sysfs > that affects all the cores and then maybe stop_machine() to propagate it to > all > the cores. Do you think having some of the cores running in sync mode and some > in async is a viable solution?
stop_machine() is an option indeed. I think it's still possible to run some cores in async while others in sync but the static key here would only be toggled when no async CPUs are left. > Probably it is worth to discuss it further once we cross that bridge. Yes. For now, a warning should do so that we don't forget. -- Catalin
