lkml.org 
[lkml]   [2021]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH 08/10] clocksource/drivers/hyper-v: Handle sched_clock differences inline
Date
From: Wei Liu <wei.liu@kernel.org> Sent: Monday, February 1, 2021 10:55 AM
>
> On Wed, Jan 27, 2021 at 12:23:43PM -0800, Michael Kelley wrote:
> [...]
> > +/*
> > + * Reference to pv_ops must be inline so objtool
> > + * detection of noinstr violations can work correctly.
> > + */
> > +static __always_inline void hv_setup_sched_clock(void *sched_clock)
>
> sched_clock_register is not trivial. Having __always_inline here is
> going to make the compiled object bloated.
>
> Given this is a static function, I don't think we need to specify any
> inline keyword. The compiler should be able to determine whether this
> function should be inlined all by itself.
>
> Wei.

There was an explicit request from Peter Zijlstra and Thomas Gleixner
to force it inline. See https://lore.kernel.org/patchwork/patch/1283635/ and
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/x86/include/asm/mshyperv.h?id=b9d8cf2eb3ceecdee3434b87763492aee9e28845

Michael

>
> > +{
> > +#ifdef CONFIG_GENERIC_SCHED_CLOCK
> > + /*
> > + * We're on an architecture with generic sched clock (not x86/x64).
> > + * The Hyper-V sched clock read function returns nanoseconds, not
> > + * the normal 100ns units of the Hyper-V synthetic clock.
> > + */
> > + sched_clock_register(sched_clock, 64, NSEC_PER_SEC);
> > +#else
> > +#ifdef CONFIG_PARAVIRT
> > + /* We're on x86/x64 *and* using PV ops */
> > + pv_ops.time.sched_clock = sched_clock;
> > +#endif
> > +#endif
> > +}
> > +
> > static bool __init hv_init_tsc_clocksource(void)
> > {
> > u64 tsc_msr;
> > --
> > 1.8.3.1
> >

\
 
 \ /
  Last update: 2021-02-04 17:30    [W:0.099 / U:1.916 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site