| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <PH0PR11MB482476E499FF0EE4A10F037BCD949@PH0PR11MB4824.namprd11.prod.outlook.com>
Date: Tue, 26 Jul 2022 01:46:41 +0000
From: "Mi, Dapeng1" <dapeng1.mi@...el.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: "Michael S. Tsirkin" <mst@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
"Bart Van Assche" <bvanassche@....org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux PM <linux-pm@...r.kernel.org>,
"Zhenyu Wang" <zhenyuw@...ux.intel.com>
Subject: RE: [PATCH] cpuidle: Move cpuidle driver forward before acpi driver
in Makefile
> From: Mi, Dapeng1
> Sent: Thursday, July 21, 2022 11:09 AM
> To: Rafael J. Wysocki <rafael@...nel.org>
> Cc: Michael S. Tsirkin <mst@...hat.com>; Arnd Bergmann <arnd@...db.de>;
> Bart Van Assche <bvanassche@....org>; Linux Kernel Mailing List <linux-
> kernel@...r.kernel.org>; Linux PM <linux-pm@...r.kernel.org>; Zhenyu
> Wang <zhenyuw@...ux.intel.com>
> Subject: RE: [PATCH] cpuidle: Move cpuidle driver forward before acpi driver
> in Makefile
>
> > From: Rafael J. Wysocki <rafael@...nel.org>
> > Sent: Wednesday, July 20, 2022 6:24 PM
> > To: Mi, Dapeng1 <dapeng1.mi@...el.com>
> > Cc: Rafael J. Wysocki <rafael@...nel.org>; Michael S. Tsirkin
> > <mst@...hat.com>; Arnd Bergmann <arnd@...db.de>; Bart Van Assche
> > <bvanassche@....org>; Linux Kernel Mailing List <linux-
> > kernel@...r.kernel.org>; Linux PM <linux-pm@...r.kernel.org>; Zhenyu
> > Wang <zhenyuw@...ux.intel.com>
> > Subject: Re: [PATCH] cpuidle: Move cpuidle driver forward before acpi
> > driver in Makefile
> >
> > On Wed, Jul 20, 2022 at 5:00 AM Mi, Dapeng1 <dapeng1.mi@...el.com>
> > wrote:
> > >
> > > > > From: Rafael J. Wysocki <rafael@...nel.org>
> > > > > Sent: Thursday, July 14, 2022 1:53 AM
> > > > > To: Mi, Dapeng1 <dapeng1.mi@...el.com>
> > > > > Cc: Rafael J. Wysocki <rafael@...nel.org>; Michael S. Tsirkin
> > > > > <mst@...hat.com>; Arnd Bergmann <arnd@...db.de>; Bart Van
> > Assche
> > > > > <bvanassche@....org>; Linux Kernel Mailing List <linux-
> > > > > kernel@...r.kernel.org>; Linux PM <linux-pm@...r.kernel.org>
> > > > > Subject: Re: [PATCH] cpuidle: Move cpuidle driver forward before
> > > > > acpi driver in Makefile
> > > > >
> > > > > On Wed, Jul 13, 2022 at 10:21 AM Dapeng Mi
> > > > > <dapeng1.mi@...el.com>
> > > > wrote:
> > > > > >
> > > > > > As long as Kconfig ACPI_PROCESSOR is enabled, ACPI_PROCESSOR
> > > > > > would select ACPI_PROCESSOR_IDLE and acpi_idle driver is
> > > > > > enabled. But in current driver loading order acpi_idle driver
> > > > > > is always loaded before cpuidle_haltpoll driver. This leads to
> > > > > > cpuidle_hatpoll driver has no chance to be loaded when it's enabled.
> > > > > >
> > > > > > Thus, move cpuidle driver forward before acpi driver and make
> > > > > > cpuidle-hatpoll driver has a chance to be run when it's enabled.
> > > > > >
> > > > > > Signed-off-by: Dapeng Mi <dapeng1.mi@...el.com>
> > > > > > ---
> > > > > > drivers/Makefile | 2 +-
> > > > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/drivers/Makefile b/drivers/Makefile index
> > > > > > 9a30842b22c5..921ed481b520 100644
> > > > > > --- a/drivers/Makefile
> > > > > > +++ b/drivers/Makefile
> > > > > > @@ -26,6 +26,7 @@ obj-y += idle/
> > > > > > # IPMI must come before ACPI in order to provide IPMI
> > > > > > opregion
> > > > support
> > > > > > obj-y += char/ipmi/
> > > > > >
> > > > > > +obj-$(CONFIG_CPU_IDLE) += cpuidle/
> > > > > > obj-$(CONFIG_ACPI) += acpi/
> > > > > >
> > > > > > # PnP must come after ACPI since it will eventually need to
> > > > > > check if
> > acpi
> > > > > > @@ -126,7 +127,6 @@ obj-$(CONFIG_EDAC) += edac/
> > > > > > obj-$(CONFIG_EISA) += eisa/
> > > > > > obj-$(CONFIG_PM_OPP) += opp/
> > > > > > obj-$(CONFIG_CPU_FREQ) += cpufreq/
> > > > > > -obj-$(CONFIG_CPU_IDLE) += cpuidle/
> > > > > > obj-y += mmc/
> > > > > > obj-y += ufs/
> > > > > > obj-$(CONFIG_MEMSTICK) += memstick/
> > > > > > --
> > > > >
> > > > > Well, this change doesn't guarantee loading haltpoll before ACPI idle.
> > > > >
> > > > > Also what if haltpoll is enabled, but the user wants ACPI idle?
> > > >
> > > > Thanks Rafael for reviewing this patch.
> > > >
> > > > acpi_idle driver and cpuidle_haltpoll driver have same
> > > > initialization level and both are initialized on the level
> > > > device_initcall. So the building order would decide the loading
> > > > sequence. Just like the intel_idle driver which also has same
> > > > initialization level (device_initcall), but as it's built before
> > > > acpi_idle driver, it would be loaded first before acpi_driver if
> > > > intel_idle
> > driver is enabled.
> > > >
> > > > There is another method to make cpuidle_haltpoll driver loaded
> > > > first before acpi_driver, it's change the initialization level to
> > > > postcore_initcall. I'm not sure which one is better, but it seems
> > > > current
> > patch is more reasonable.
> > > >
> > > > There is an parameter "force" to manage the haltpoll enabling. If
> > > > user want to use ACPI idle, it can change this parameter to
> > > > disable
> > haltpolll driver.
> >
> > That would require things to be appended to the kernel command line in
> > cases where that's not necessary today and that's not acceptable.
> >
> The haltpoll driver's "force" parameter is false by default, we don't need to
> add extra command line options in most cases except we want to enable the
> haltpolling driver.
>
> > What you really seem to be wanting to do is to use haltpoll instead of
> > ACPI idle. Is that correct?
>
> Yes, I'm trying to enable guest halt polling to improve the performance of
> some Virtual Machine. But I found the halt poll driver can't be enabled as
> long as acpi idle driver is enabled. I tried to disable the acpi idle first, but I
> found there is no parameter to enable/disable acpi idle driver except
> disabling the Kconfig "CONFIG_ACPI_PROCESSOR_IDLE", and but
> unfortunately Kconfig "ACPI_PROCESSOR" would enable
> "ACPI_PROCESSOR_IDLE" by default. If I want to disable acpi_idle driver, I
> have to disable the "ACPI_PROCESSOR", but this would cause acpi throttling
> and acpi thermal are also disabled. That's not what I want. That's why I do this
> change to make halt poll driver has a chance to run without disable the
> entire acpi processor functionality .
>
Any feedback? Thanks.
Powered by blists - more mailing lists