Messages in this thread | | | Date | Wed, 27 Oct 2021 13:20:23 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH] arm64: Select POSIX_CPU_TIMERS_TASK_WORK |
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On Wed, 27 Oct 2021 12:26:58 +0100, Mark Rutland <mark.rutland@arm.com> wrote: > > [adding Marc Z to Cc, since this affects KVM] > > On Mon, Oct 18, 2021 at 04:47:13PM +0200, Nicolas Saenz Julienne wrote: > > With 6caa5812e2d1 ("KVM: arm64: Use generic KVM xfer to guest work > > function") all arm64 exit paths are properly equipped to handle the > > POSIX timers' task work. > > > > Deferring timer callbacks to thread context, not only limits the amount > > of time spent in hard interrupt context, but is a safer > > implementation[1], and will allow PREEMPT_RT setups to use KVM[2]. > > > > So let's enable POSIX_CPU_TIMERS_TASK_WORK on arm64. > > > > [1] https://lore.kernel.org/all/20200716201923.228696399@linutronix.de/ > > [2] https://www.spinics.net/lists/linux-rt-users/msg24860.html > > Trivial nit: could we please make that second link: > > https://lore.kernel.org/linux-rt-users/87v92bdnlx.ffs@tglx/ > > > Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> > > Regardless, this makes sense to me, and given you've tested it: > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > Thanks, > Mark. > > > > > --- > > > > This was tested by running all relevant kernel timer self-tests and > > making sure KVM still works as expected. > > > > arch/arm64/Kconfig | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index 789036cf74f5..ce0d0d254542 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -191,6 +191,7 @@ config ARM64 > > select HAVE_PERF_REGS > > select HAVE_PERF_USER_STACK_DUMP > > select HAVE_REGS_AND_STACK_ACCESS_API > > + select HAVE_POSIX_CPU_TIMERS_TASK_WORK > > select HAVE_FUNCTION_ARG_ACCESS_API > > select HAVE_FUTEX_CMPXCHG if FUTEX > > select MMU_GATHER_RCU_TABLE_FREE
Looks reasonable to me.
Acked-by: Marc Zyngier <maz@kernel.org>
M.
-- Without deviation from the norm, progress is not possible.
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