From: Gautham R Shenoy <ego@linux.vnet.ibm.com>
To: Nathan Lynch <nathanl@linux.ibm.com>
Cc: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
Tyrel Datwyler <tyreld@linux.ibm.com>,
linux-kernel@vger.kernel.org,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 1/5] powerpc: Move idle_loop_prolog()/epilog() functions to header file
Date: Mon, 24 Feb 2020 10:25:06 +0530 [thread overview]
Message-ID: <20200224045506.GA12846@in.ibm.com> (raw)
In-Reply-To: <87lfowt22z.fsf@linux.ibm.com>
Hello Nathan,
On Fri, Feb 21, 2020 at 09:03:16AM -0600, Nathan Lynch wrote:
> "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> writes:
>
> > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
> >
> > Currently prior to entering an idle state on a Linux Guest, the
> > pseries cpuidle driver implement an idle_loop_prolog() and
> > idle_loop_epilog() functions which ensure that idle_purr is correctly
> > computed, and the hypervisor is informed that the CPU cycles have been
> > donated.
> >
> > These prolog and epilog functions are also required in the default
> > idle call, i.e pseries_lpar_idle(). Hence move these accessor
> > functions to a common header file and call them from
> > pseries_lpar_idle(). Since the existing header files such as
> > asm/processor.h have enough clutter, create a new header file
> > asm/idle.h.
> >
> > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> > ---
> > arch/powerpc/include/asm/idle.h | 27 +++++++++++++++++++++++++++
> > arch/powerpc/platforms/pseries/setup.c | 7 +++++--
> > drivers/cpuidle/cpuidle-pseries.c | 24 +-----------------------
> > 3 files changed, 33 insertions(+), 25 deletions(-)
> > create mode 100644 arch/powerpc/include/asm/idle.h
> >
> > diff --git a/arch/powerpc/include/asm/idle.h b/arch/powerpc/include/asm/idle.h
> > new file mode 100644
> > index 0000000..f32a7d8
> > --- /dev/null
> > +++ b/arch/powerpc/include/asm/idle.h
> > @@ -0,0 +1,27 @@
> > +#ifndef _ASM_POWERPC_IDLE_H
> > +#define _ASM_POWERPC_IDLE_H
> > +#include <asm/runlatch.h>
> > +
> > +static inline void idle_loop_prolog(unsigned long *in_purr)
> > +{
> > + ppc64_runlatch_off();
> > + *in_purr = mfspr(SPRN_PURR);
> > + /*
> > + * Indicate to the HV that we are idle. Now would be
> > + * a good time to find other work to dispatch.
> > + */
> > + get_lppaca()->idle = 1;
> > +}
> > +
> > +static inline void idle_loop_epilog(unsigned long in_purr)
> > +{
> > + u64 wait_cycles;
> > +
> > + wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
> > + wait_cycles += mfspr(SPRN_PURR) - in_purr;
> > + get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
> > + get_lppaca()->idle = 0;
> > +
> > + ppc64_runlatch_on();
> > +}
> > +#endif
>
> Looks fine and correct as a cleanup, but asm/include/idle.h and
> idle_loop_prolog, idle_loop_epilog, strike me as too generic for
> pseries-specific code.
Should it be prefixed with pseries , i.e pseries_idle_prolog()
and pseries_idle_epilog() ?
Also, I am planning another round of cleanup to move all the
idle-related declaration from asm/include/processor.h to
asm/include/idle.h
next prev parent reply other threads:[~2020-02-24 4:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 5:18 [PATCH v2 0/5] Track and expose idle PURR and SPURR ticks Gautham R. Shenoy
2020-02-21 5:18 ` [PATCH v2 1/5] powerpc: Move idle_loop_prolog()/epilog() functions to header file Gautham R. Shenoy
2020-02-21 15:03 ` Nathan Lynch
2020-02-24 4:55 ` Gautham R Shenoy [this message]
2020-03-06 17:06 ` Nathan Lynch
2020-02-21 5:18 ` [PATCH v2 2/5] powerpc/idle: Add accessor function to always read latest idle PURR Gautham R. Shenoy
2020-02-21 5:18 ` [PATCH v2 3/5] powerpc/pseries: Account for SPURR ticks on idle CPUs Gautham R. Shenoy
2020-02-21 16:47 ` Nathan Lynch
2020-02-24 5:05 ` Gautham R Shenoy
2020-02-21 5:18 ` [PATCH v2 4/5] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU Gautham R. Shenoy
2020-02-21 16:50 ` Nathan Lynch
2020-02-24 5:14 ` Gautham R Shenoy
2020-02-25 10:20 ` Naveen N. Rao
2020-03-06 17:03 ` Nathan Lynch
2020-03-06 17:35 ` Naveen N. Rao
2020-02-21 5:18 ` [PATCH v2 5/5] Documentation: Document sysfs interfaces purr, spurr, idle_purr, idle_spurr Gautham R. Shenoy
2020-02-21 16:55 ` Nathan Lynch
2020-02-24 5:15 ` Gautham R Shenoy
2020-02-24 4:17 ` [PATCH v2 0/5] Track and expose idle PURR and SPURR ticks Kamalesh Babulal
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