| Message ID | 20170209092525.6654-7-juri.lelli@arm.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Thu, Feb 09, 2017 at 09:25:22AM +0000, Juri Lelli wrote: > arm and arm64 share lot of code relative to parsing CPU capacity > information from DT, using that information for appropriate scaling and > exposing a sysfs interface for chaging such values at runtime. > > Factorize such code in a common place (driver/base/arch_topology.c) in > preparation for further additions. > > Suggested-by: Will Deacon <will.deacon@arm.com> > Suggested-by: Mark Rutland <mark.rutland@arm.com> > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > Cc: Russell King <linux@armlinux.org.uk> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Juri Lelli <juri.lelli@arm.com> > --- > > Changes from v1: > - keep the original GPLv2 header > --- > arch/arm/Kconfig | 1 + > arch/arm/kernel/topology.c | 213 ++------------------------------------ > arch/arm64/Kconfig | 1 + > arch/arm64/kernel/topology.c | 219 +-------------------------------------- > drivers/base/Kconfig | 8 ++ > drivers/base/Makefile | 1 + > drivers/base/arch_topology.c | 237 +++++++++++++++++++++++++++++++++++++++++++ > 7 files changed, 257 insertions(+), 423 deletions(-) > create mode 100644 drivers/base/arch_topology.c Ah, so you want _me_ to maintain this, ok, I better review it... > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -339,4 +339,12 @@ config CMA_ALIGNMENT > > endif > > +config GENERIC_ARCH_TOPOLOGY > + bool > + help > + Enable support for architectures common topology code: e.g., parsing > + CPU capacity information from DT, usage of such information for > + appropriate scaling, sysfs interface for changing capacity values at > + runtime. Mix of spaces and tabs :( > + > endmenu > diff --git a/drivers/base/Makefile b/drivers/base/Makefile > index f2816f6ff76a..397e5c344e6a 100644 > --- a/drivers/base/Makefile > +++ b/drivers/base/Makefile > @@ -23,6 +23,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o > obj-$(CONFIG_PINCTRL) += pinctrl.o > obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o > obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o > +obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o > > obj-y += test/ > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > new file mode 100644 > index 000000000000..c1dd430adad2 > --- /dev/null > +++ b/drivers/base/arch_topology.c > @@ -0,0 +1,237 @@ > +/* > + * driver/base/arch_topology.c - Arch specific cpu topology information No need to keep the filename in the file, you know what it is called :) > + * > + * Copyright (C) 2016, ARM Ltd. > + * Written by: Juri Lelli, ARM Ltd. > + * > + * This file is subject to the terms and conditions of the GNU General Public > + * License. See the file "COPYING" in the main directory of this archive > + * for more details. So, v2 only? Please be specific. Even better yet, use a SPDX header if you want to, those are always nice. > + */ > + > +#include <linux/acpi.h> > +#include <linux/cpu.h> > +#include <linux/cpufreq.h> > +#include <linux/device.h> > +#include <linux/of.h> > +#include <linux/slab.h> > +#include <linux/string.h> > +#include <linux/topology.h> > + > +static DEFINE_MUTEX(cpu_scale_mutex); > +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; > + > +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) Why do you have sd here? You never use it: > +{ > + return per_cpu(cpu_scale, cpu); See? What am I missing? > +} > + > +void set_capacity_scale(unsigned int cpu, unsigned long capacity) > +{ > + per_cpu(cpu_scale, cpu) = capacity; > +} > + > +static ssize_t cpu_capacity_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct cpu *cpu = container_of(dev, struct cpu, dev); > + > + return sprintf(buf, "%lu\n", > + arch_scale_cpu_capacity(NULL, cpu->dev.id)); > +} > + > +static ssize_t cpu_capacity_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, > + size_t count) > +{ > + struct cpu *cpu = container_of(dev, struct cpu, dev); > + int this_cpu = cpu->dev.id, i; new line for: int i; please. > + unsigned long new_capacity; > + ssize_t ret; > + > + if (count) { if (!count) return 0; then you can get on with the rest of the logic. Don't indent if you don't have to. > + ret = kstrtoul(buf, 0, &new_capacity); > + if (ret) > + return ret; > + if (new_capacity > SCHED_CAPACITY_SCALE) > + return -EINVAL; > + > + mutex_lock(&cpu_scale_mutex); > + for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) > + set_capacity_scale(i, new_capacity); > + mutex_unlock(&cpu_scale_mutex); > + } > + > + return count; > +} No documentation for these sysfs file? Not good :( > + > +static DEVICE_ATTR_RW(cpu_capacity); > + > +static int register_cpu_capacity_sysctl(void) > +{ > + int i; > + struct device *cpu; > + > + for_each_possible_cpu(i) { > + cpu = get_cpu_device(i); > + if (!cpu) { > + pr_err("%s: too early to get CPU%d device!\n", > + __func__, i); What is this going to help with? > + continue; > + } > + device_create_file(cpu, &dev_attr_cpu_capacity); You realize you just raced userspace, right? Why do it this way and not register the files when the CPU device is created/removed? > + } > + > + return 0; > +} > +subsys_initcall(register_cpu_capacity_sysctl); > + > +u32 capacity_scale; > +u32 *raw_capacity; > +bool cap_parsing_failed; globals? really? That's bold :( > + > +void normalize_cpu_capacity(void) naming is hard, but try to put a good, descriptive, prefix on everything you are exporting in the same file, the same prefix. cpu_capacity_normalize()? cpu_capacity_register_sysctl()? and so on. > +{ > + u64 capacity; > + int cpu; > + > + if (!raw_capacity || cap_parsing_failed) > + return; > + > + pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); > + mutex_lock(&cpu_scale_mutex); > + for_each_possible_cpu(cpu) { > + pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", > + cpu, raw_capacity[cpu]); > + capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) > + / capacity_scale; > + set_capacity_scale(cpu, capacity); > + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", > + cpu, arch_scale_cpu_capacity(NULL, cpu)); > + } > + mutex_unlock(&cpu_scale_mutex); > +} > + > +int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) cpu_capacity_parse()? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Greg, On 10/02/17 15:28, Greg KH wrote: > On Thu, Feb 09, 2017 at 09:25:22AM +0000, Juri Lelli wrote: > > arm and arm64 share lot of code relative to parsing CPU capacity > > information from DT, using that information for appropriate scaling and > > exposing a sysfs interface for chaging such values at runtime. > > > > Factorize such code in a common place (driver/base/arch_topology.c) in > > preparation for further additions. > > > > Suggested-by: Will Deacon <will.deacon@arm.com> > > Suggested-by: Mark Rutland <mark.rutland@arm.com> > > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Russell King <linux@armlinux.org.uk> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Will Deacon <will.deacon@arm.com> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Signed-off-by: Juri Lelli <juri.lelli@arm.com> > > --- > > > > Changes from v1: > > - keep the original GPLv2 header > > --- > > arch/arm/Kconfig | 1 + > > arch/arm/kernel/topology.c | 213 ++------------------------------------ > > arch/arm64/Kconfig | 1 + > > arch/arm64/kernel/topology.c | 219 +-------------------------------------- > > drivers/base/Kconfig | 8 ++ > > drivers/base/Makefile | 1 + > > drivers/base/arch_topology.c | 237 +++++++++++++++++++++++++++++++++++++++++++ > > 7 files changed, 257 insertions(+), 423 deletions(-) > > create mode 100644 drivers/base/arch_topology.c > > Ah, so you want _me_ to maintain this, ok, I better review it... > This has been suggested as a possible way to stop replicating code between arm and arm64 (and possibly other archs in the future). Are you in principle OK with it? Thanks a lot for your comments, please find my answers below. > > --- a/drivers/base/Kconfig > > +++ b/drivers/base/Kconfig > > @@ -339,4 +339,12 @@ config CMA_ALIGNMENT > > > > endif > > > > +config GENERIC_ARCH_TOPOLOGY > > + bool > > + help > > + Enable support for architectures common topology code: e.g., parsing > > + CPU capacity information from DT, usage of such information for > > + appropriate scaling, sysfs interface for changing capacity values at > > + runtime. > > Mix of spaces and tabs :( > Argh. :( > > + > > endmenu > > diff --git a/drivers/base/Makefile b/drivers/base/Makefile > > index f2816f6ff76a..397e5c344e6a 100644 > > --- a/drivers/base/Makefile > > +++ b/drivers/base/Makefile > > @@ -23,6 +23,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o > > obj-$(CONFIG_PINCTRL) += pinctrl.o > > obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o > > obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o > > +obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o > > > > obj-y += test/ > > > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > > new file mode 100644 > > index 000000000000..c1dd430adad2 > > --- /dev/null > > +++ b/drivers/base/arch_topology.c > > @@ -0,0 +1,237 @@ > > +/* > > + * driver/base/arch_topology.c - Arch specific cpu topology information > > No need to keep the filename in the file, you know what it is called :) > OK, removed. > > + * > > + * Copyright (C) 2016, ARM Ltd. > > + * Written by: Juri Lelli, ARM Ltd. > > + * > > + * This file is subject to the terms and conditions of the GNU General Public > > + * License. See the file "COPYING" in the main directory of this archive > > + * for more details. > > So, v2 only? Please be specific. Even better yet, use a SPDX header if > you want to, those are always nice. > Yes, v2 only. * for more details. + * + * Released under the GPLv2 only. + * SPDX-License-Identifier: GPL-2.0 Would do, right? > > + */ > > + > > +#include <linux/acpi.h> > > +#include <linux/cpu.h> > > +#include <linux/cpufreq.h> > > +#include <linux/device.h> > > +#include <linux/of.h> > > +#include <linux/slab.h> > > +#include <linux/string.h> > > +#include <linux/topology.h> > > + > > +static DEFINE_MUTEX(cpu_scale_mutex); > > +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; > > + > > +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) > > Why do you have sd here? You never use it: > > > +{ > > + return per_cpu(cpu_scale, cpu); > > See? What am I missing? > This is how this function is defined in kernel/sched/sched.h: #ifndef arch_scale_cpu_capacity static __always_inline unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) { if (sd && (sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1)) return sd->smt_gain / sd->span_weight; return SCHED_CAPACITY_SCALE; } #endif and in this case the sd argument is used: there is a call site in fair.c that passes a non NULL sd, updated_cpu_capacity(). A following set of patches will re-define the function so that the drivers one gets used by the kernel (only arm and arm64 will currently want this), with something like this in arch code #define arch_scale_cpu_capacity atd_scale_cpu_capacity Please note that last patch of this set renames this function atd_scale_ cpu_capacity, to (hopefully) make this approach more clear. Does it make more sense to you? > > +} > > + > > +void set_capacity_scale(unsigned int cpu, unsigned long capacity) > > +{ > > + per_cpu(cpu_scale, cpu) = capacity; > > +} > > + > > +static ssize_t cpu_capacity_show(struct device *dev, > > + struct device_attribute *attr, > > + char *buf) > > +{ > > + struct cpu *cpu = container_of(dev, struct cpu, dev); > > + > > + return sprintf(buf, "%lu\n", > > + arch_scale_cpu_capacity(NULL, cpu->dev.id)); > > +} > > + > > +static ssize_t cpu_capacity_store(struct device *dev, > > + struct device_attribute *attr, > > + const char *buf, > > + size_t count) > > +{ > > + struct cpu *cpu = container_of(dev, struct cpu, dev); > > + int this_cpu = cpu->dev.id, i; > > new line for: > int i; > please. > Sure. > > + unsigned long new_capacity; > > + ssize_t ret; > > + > > + if (count) { > > if (!count) > return 0; > > then you can get on with the rest of the logic. Don't indent if you > don't have to. > Right. > > + ret = kstrtoul(buf, 0, &new_capacity); > > + if (ret) > > + return ret; > > + if (new_capacity > SCHED_CAPACITY_SCALE) > > + return -EINVAL; > > + > > + mutex_lock(&cpu_scale_mutex); > > + for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) > > + set_capacity_scale(i, new_capacity); > > + mutex_unlock(&cpu_scale_mutex); > > + } > > + > > + return count; > > +} > > No documentation for these sysfs file? Not good :( > Patch 2/9 introduces some documentation. There is already more in Documentation/devicetree/bindings/arm/cpu-capacity.txt. Do you think I should improve further? > > + > > +static DEVICE_ATTR_RW(cpu_capacity); > > + > > +static int register_cpu_capacity_sysctl(void) > > +{ > > + int i; > > + struct device *cpu; > > + > > + for_each_possible_cpu(i) { > > + cpu = get_cpu_device(i); > > + if (!cpu) { > > + pr_err("%s: too early to get CPU%d device!\n", > > + __func__, i); > > What is this going to help with? > Not much I guess, I can remove it. > > + continue; > > + } > > + device_create_file(cpu, &dev_attr_cpu_capacity); > > You realize you just raced userspace, right? Why do it this way and not > register the files when the CPU device is created/removed? > Humm, my intention for doing it this way is that I'd like to make all the code dealing with cpu_capacity confined in a single place (this file), without the need to modify other files. > > + } > > + > > + return 0; > > +} > > +subsys_initcall(register_cpu_capacity_sysctl); AFAIU, for both arm and arm64 CPU device is registered with a subsys_initcall(topology_init), so I'm doing the same. Other archs seem to do similar things. Could you explain a little more why this is a problem? > > + > > +u32 capacity_scale; > > +u32 *raw_capacity; > > +bool cap_parsing_failed; > > globals? really? That's bold :( > Yeah, ugly. However, patch 7/9 is making cap_parsing_failed static. The other two can be made static already, I should have done that in the first place. :( BTW, with this set I'm trying to incrementally fix things (after moving code in the new place), does it look reasonable to you or would you prefer to squash intermediate steps? > > + > > +void normalize_cpu_capacity(void) > > naming is hard, but try to put a good, descriptive, prefix on everything > you are exporting in the same file, the same prefix. > > cpu_capacity_normalize()? > cpu_capacity_register_sysctl()? > > and so on. > > > +{ > > + u64 capacity; > > + int cpu; > > + > > + if (!raw_capacity || cap_parsing_failed) > > + return; > > + > > + pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); > > + mutex_lock(&cpu_scale_mutex); > > + for_each_possible_cpu(cpu) { > > + pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", > > + cpu, raw_capacity[cpu]); > > + capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) > > + / capacity_scale; > > + set_capacity_scale(cpu, capacity); > > + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", > > + cpu, arch_scale_cpu_capacity(NULL, cpu)); > > + } > > + mutex_unlock(&cpu_scale_mutex); > > +} > > + > > +int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) > > cpu_capacity_parse()? > OK, I'll try to fix the naming as you suggest. Thanks! Best, - Juri -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Feb 10, 2017 at 8:28 AM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Thu, Feb 09, 2017 at 09:25:22AM +0000, Juri Lelli wrote: >> arm and arm64 share lot of code relative to parsing CPU capacity >> information from DT, using that information for appropriate scaling and >> exposing a sysfs interface for chaging such values at runtime. >> >> Factorize such code in a common place (driver/base/arch_topology.c) in >> preparation for further additions. >> >> Suggested-by: Will Deacon <will.deacon@arm.com> >> Suggested-by: Mark Rutland <mark.rutland@arm.com> >> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Russell King <linux@armlinux.org.uk> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> Signed-off-by: Juri Lelli <juri.lelli@arm.com> >> --- >> >> Changes from v1: >> - keep the original GPLv2 header >> --- >> arch/arm/Kconfig | 1 + >> arch/arm/kernel/topology.c | 213 ++------------------------------------ >> arch/arm64/Kconfig | 1 + >> arch/arm64/kernel/topology.c | 219 +-------------------------------------- >> drivers/base/Kconfig | 8 ++ >> drivers/base/Makefile | 1 + >> drivers/base/arch_topology.c | 237 +++++++++++++++++++++++++++++++++++++++++++ >> 7 files changed, 257 insertions(+), 423 deletions(-) >> create mode 100644 drivers/base/arch_topology.c > > Ah, so you want _me_ to maintain this, ok, I better review it... > >> --- a/drivers/base/Kconfig >> +++ b/drivers/base/Kconfig >> @@ -339,4 +339,12 @@ config CMA_ALIGNMENT >> >> endif >> >> +config GENERIC_ARCH_TOPOLOGY >> + bool >> + help >> + Enable support for architectures common topology code: e.g., parsing >> + CPU capacity information from DT, usage of such information for >> + appropriate scaling, sysfs interface for changing capacity values at >> + runtime. > > Mix of spaces and tabs :( > >> + >> endmenu >> diff --git a/drivers/base/Makefile b/drivers/base/Makefile >> index f2816f6ff76a..397e5c344e6a 100644 >> --- a/drivers/base/Makefile >> +++ b/drivers/base/Makefile >> @@ -23,6 +23,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o >> obj-$(CONFIG_PINCTRL) += pinctrl.o >> obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o >> obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o >> +obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o >> >> obj-y += test/ >> >> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c >> new file mode 100644 >> index 000000000000..c1dd430adad2 >> --- /dev/null >> +++ b/drivers/base/arch_topology.c >> @@ -0,0 +1,237 @@ >> +/* >> + * driver/base/arch_topology.c - Arch specific cpu topology information > > No need to keep the filename in the file, you know what it is called :) > >> + * >> + * Copyright (C) 2016, ARM Ltd. >> + * Written by: Juri Lelli, ARM Ltd. >> + * >> + * This file is subject to the terms and conditions of the GNU General Public >> + * License. See the file "COPYING" in the main directory of this archive >> + * for more details. > > So, v2 only? Please be specific. Even better yet, use a SPDX header if > you want to, those are always nice. Sorry to hijack this thread, but you're recommending SPDX now? You seemed pretty negative on it last time it came up[1]. Or was that just in context of the churn of converting existing files? Personally, I like the use of SPDX tags over free form license text and would like to encourage it for dts files. Rob [1] https://lkml.org/lkml/2015/2/5/65
On Wed, Feb 15, 2017 at 05:17:05PM -0600, Rob Herring wrote: > On Fri, Feb 10, 2017 at 8:28 AM, Greg KH <gregkh@linuxfoundation.org> wrote: > >> + * > >> + * Copyright (C) 2016, ARM Ltd. > >> + * Written by: Juri Lelli, ARM Ltd. > >> + * > >> + * This file is subject to the terms and conditions of the GNU General Public > >> + * License. See the file "COPYING" in the main directory of this archive > >> + * for more details. > > > > So, v2 only? Please be specific. Even better yet, use a SPDX header if > > you want to, those are always nice. > > Sorry to hijack this thread, but you're recommending SPDX now? You > seemed pretty negative on it last time it came up[1]. Or was that just > in context of the churn of converting existing files? It was in the context of someone trying to tell someone else to do the work for them of converting all of the existing files to use SPDX. I've never refused a patch from someone adding SPDX identifiers to the kernel, in fact, _I'm_ the only one that has ever used such an identifier on a kernel file :) > Personally, I like the use of SPDX tags over free form license text > and would like to encourage it for dts files. Sure, go ahead, I'd encourage it. thanks, greg k-h
Hi Greg, did you have a chance to have a look at my replies below? It would be really helpful to understand from you how to move forward with this set. Best Regards, - Juri On 13/02/17 15:09, Juri Lelli wrote: > Hi Greg, > > On 10/02/17 15:28, Greg KH wrote: > > On Thu, Feb 09, 2017 at 09:25:22AM +0000, Juri Lelli wrote: > > > arm and arm64 share lot of code relative to parsing CPU capacity > > > information from DT, using that information for appropriate scaling and > > > exposing a sysfs interface for chaging such values at runtime. > > > > > > Factorize such code in a common place (driver/base/arch_topology.c) in > > > preparation for further additions. > > > > > > Suggested-by: Will Deacon <will.deacon@arm.com> > > > Suggested-by: Mark Rutland <mark.rutland@arm.com> > > > Suggested-by: Catalin Marinas <catalin.marinas@arm.com> > > > Cc: Russell King <linux@armlinux.org.uk> > > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > > Cc: Will Deacon <will.deacon@arm.com> > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > Signed-off-by: Juri Lelli <juri.lelli@arm.com> > > > --- > > > > > > Changes from v1: > > > - keep the original GPLv2 header > > > --- > > > arch/arm/Kconfig | 1 + > > > arch/arm/kernel/topology.c | 213 ++------------------------------------ > > > arch/arm64/Kconfig | 1 + > > > arch/arm64/kernel/topology.c | 219 +-------------------------------------- > > > drivers/base/Kconfig | 8 ++ > > > drivers/base/Makefile | 1 + > > > drivers/base/arch_topology.c | 237 +++++++++++++++++++++++++++++++++++++++++++ > > > 7 files changed, 257 insertions(+), 423 deletions(-) > > > create mode 100644 drivers/base/arch_topology.c > > > > Ah, so you want _me_ to maintain this, ok, I better review it... > > > > This has been suggested as a possible way to stop replicating code between arm > and arm64 (and possibly other archs in the future). Are you in principle OK > with it? > > Thanks a lot for your comments, please find my answers below. > > > > --- a/drivers/base/Kconfig > > > +++ b/drivers/base/Kconfig > > > @@ -339,4 +339,12 @@ config CMA_ALIGNMENT > > > > > > endif > > > > > > +config GENERIC_ARCH_TOPOLOGY > > > + bool > > > + help > > > + Enable support for architectures common topology code: e.g., parsing > > > + CPU capacity information from DT, usage of such information for > > > + appropriate scaling, sysfs interface for changing capacity values at > > > + runtime. > > > > Mix of spaces and tabs :( > > > > Argh. :( > > > > + > > > endmenu > > > diff --git a/drivers/base/Makefile b/drivers/base/Makefile > > > index f2816f6ff76a..397e5c344e6a 100644 > > > --- a/drivers/base/Makefile > > > +++ b/drivers/base/Makefile > > > @@ -23,6 +23,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o > > > obj-$(CONFIG_PINCTRL) += pinctrl.o > > > obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o > > > obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o > > > +obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o > > > > > > obj-y += test/ > > > > > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > > > new file mode 100644 > > > index 000000000000..c1dd430adad2 > > > --- /dev/null > > > +++ b/drivers/base/arch_topology.c > > > @@ -0,0 +1,237 @@ > > > +/* > > > + * driver/base/arch_topology.c - Arch specific cpu topology information > > > > No need to keep the filename in the file, you know what it is called :) > > > > OK, removed. > > > > + * > > > + * Copyright (C) 2016, ARM Ltd. > > > + * Written by: Juri Lelli, ARM Ltd. > > > + * > > > + * This file is subject to the terms and conditions of the GNU General Public > > > + * License. See the file "COPYING" in the main directory of this archive > > > + * for more details. > > > > So, v2 only? Please be specific. Even better yet, use a SPDX header if > > you want to, those are always nice. > > > > Yes, v2 only. > > * for more details. > + * > + * Released under the GPLv2 only. > + * SPDX-License-Identifier: GPL-2.0 > > Would do, right? > > > > + */ > > > + > > > +#include <linux/acpi.h> > > > +#include <linux/cpu.h> > > > +#include <linux/cpufreq.h> > > > +#include <linux/device.h> > > > +#include <linux/of.h> > > > +#include <linux/slab.h> > > > +#include <linux/string.h> > > > +#include <linux/topology.h> > > > + > > > +static DEFINE_MUTEX(cpu_scale_mutex); > > > +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; > > > + > > > +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) > > > > Why do you have sd here? You never use it: > > > > > +{ > > > + return per_cpu(cpu_scale, cpu); > > > > See? What am I missing? > > > > This is how this function is defined in kernel/sched/sched.h: > > #ifndef arch_scale_cpu_capacity > static __always_inline > unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) > { > if (sd && (sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1)) > return sd->smt_gain / sd->span_weight; > > return SCHED_CAPACITY_SCALE; > } > #endif > > and in this case the sd argument is used: there is a call site in fair.c > that passes a non NULL sd, updated_cpu_capacity(). > > A following set of patches will re-define the function so that the > drivers one gets used by the kernel (only arm and arm64 will currently > want this), with something like this in arch code > > #define arch_scale_cpu_capacity atd_scale_cpu_capacity > > Please note that last patch of this set renames this function atd_scale_ > cpu_capacity, to (hopefully) make this approach more clear. > > Does it make more sense to you? > > > > +} > > > + > > > +void set_capacity_scale(unsigned int cpu, unsigned long capacity) > > > +{ > > > + per_cpu(cpu_scale, cpu) = capacity; > > > +} > > > + > > > +static ssize_t cpu_capacity_show(struct device *dev, > > > + struct device_attribute *attr, > > > + char *buf) > > > +{ > > > + struct cpu *cpu = container_of(dev, struct cpu, dev); > > > + > > > + return sprintf(buf, "%lu\n", > > > + arch_scale_cpu_capacity(NULL, cpu->dev.id)); > > > +} > > > + > > > +static ssize_t cpu_capacity_store(struct device *dev, > > > + struct device_attribute *attr, > > > + const char *buf, > > > + size_t count) > > > +{ > > > + struct cpu *cpu = container_of(dev, struct cpu, dev); > > > + int this_cpu = cpu->dev.id, i; > > > > new line for: > > int i; > > please. > > > > Sure. > > > > + unsigned long new_capacity; > > > + ssize_t ret; > > > + > > > + if (count) { > > > > if (!count) > > return 0; > > > > then you can get on with the rest of the logic. Don't indent if you > > don't have to. > > > > Right. > > > > + ret = kstrtoul(buf, 0, &new_capacity); > > > + if (ret) > > > + return ret; > > > + if (new_capacity > SCHED_CAPACITY_SCALE) > > > + return -EINVAL; > > > + > > > + mutex_lock(&cpu_scale_mutex); > > > + for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) > > > + set_capacity_scale(i, new_capacity); > > > + mutex_unlock(&cpu_scale_mutex); > > > + } > > > + > > > + return count; > > > +} > > > > No documentation for these sysfs file? Not good :( > > > > Patch 2/9 introduces some documentation. There is already more in > Documentation/devicetree/bindings/arm/cpu-capacity.txt. > > Do you think I should improve further? > > > > + > > > +static DEVICE_ATTR_RW(cpu_capacity); > > > + > > > +static int register_cpu_capacity_sysctl(void) > > > +{ > > > + int i; > > > + struct device *cpu; > > > + > > > + for_each_possible_cpu(i) { > > > + cpu = get_cpu_device(i); > > > + if (!cpu) { > > > + pr_err("%s: too early to get CPU%d device!\n", > > > + __func__, i); > > > > What is this going to help with? > > > > Not much I guess, I can remove it. > > > > + continue; > > > + } > > > + device_create_file(cpu, &dev_attr_cpu_capacity); > > > > You realize you just raced userspace, right? Why do it this way and not > > register the files when the CPU device is created/removed? > > > > Humm, my intention for doing it this way is that I'd like to make all > the code dealing with cpu_capacity confined in a single place (this > file), without the need to modify other files. > > > > + } > > > + > > > + return 0; > > > +} > > > +subsys_initcall(register_cpu_capacity_sysctl); > > AFAIU, for both arm and arm64 CPU device is registered with a > subsys_initcall(topology_init), so I'm doing the same. Other archs seem to do > similar things. Could you explain a little more why this is a problem? > > > > + > > > +u32 capacity_scale; > > > +u32 *raw_capacity; > > > +bool cap_parsing_failed; > > > > globals? really? That's bold :( > > > > Yeah, ugly. However, patch 7/9 is making cap_parsing_failed static. The other > two can be made static already, I should have done that in the first place. :( > > BTW, with this set I'm trying to incrementally fix things (after moving code in > the new place), does it look reasonable to you or would you prefer to squash > intermediate steps? > > > > + > > > +void normalize_cpu_capacity(void) > > > > naming is hard, but try to put a good, descriptive, prefix on everything > > you are exporting in the same file, the same prefix. > > > > cpu_capacity_normalize()? > > cpu_capacity_register_sysctl()? > > > > and so on. > > > > > +{ > > > + u64 capacity; > > > + int cpu; > > > + > > > + if (!raw_capacity || cap_parsing_failed) > > > + return; > > > + > > > + pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); > > > + mutex_lock(&cpu_scale_mutex); > > > + for_each_possible_cpu(cpu) { > > > + pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", > > > + cpu, raw_capacity[cpu]); > > > + capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) > > > + / capacity_scale; > > > + set_capacity_scale(cpu, capacity); > > > + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", > > > + cpu, arch_scale_cpu_capacity(NULL, cpu)); > > > + } > > > + mutex_unlock(&cpu_scale_mutex); > > > +} > > > + > > > +int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) > > > > cpu_capacity_parse()? > > > > OK, I'll try to fix the naming as you suggest. Thanks! > > Best, > > - Juri
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 186c4c214e0a..6dd5736c1e3c 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -19,6 +19,7 @@ config ARM select EDAC_SUPPORT select EDAC_ATOMIC_SCRUB select GENERIC_ALLOCATOR + select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI) select GENERIC_CLOCKEVENTS_BROADCAST if SMP select GENERIC_EARLY_IOREMAP diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index c760a321935b..51e9ed6439f1 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -43,75 +43,10 @@ * to run the rebalance_domains for all idle cores and the cpu_capacity can be * updated during this sequence. */ -static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; -static DEFINE_MUTEX(cpu_scale_mutex); -unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) -{ - return per_cpu(cpu_scale, cpu); -} - -static void set_capacity_scale(unsigned int cpu, unsigned long capacity) -{ - per_cpu(cpu_scale, cpu) = capacity; -} - -static ssize_t cpu_capacity_show(struct device *dev, - struct device_attribute *attr, - char *buf) -{ - struct cpu *cpu = container_of(dev, struct cpu, dev); - - return sprintf(buf, "%lu\n", - arch_scale_cpu_capacity(NULL, cpu->dev.id)); -} - -static ssize_t cpu_capacity_store(struct device *dev, - struct device_attribute *attr, - const char *buf, - size_t count) -{ - struct cpu *cpu = container_of(dev, struct cpu, dev); - int this_cpu = cpu->dev.id, i; - unsigned long new_capacity; - ssize_t ret; - - if (count) { - ret = kstrtoul(buf, 0, &new_capacity); - if (ret) - return ret; - if (new_capacity > SCHED_CAPACITY_SCALE) - return -EINVAL; - - mutex_lock(&cpu_scale_mutex); - for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) - set_capacity_scale(i, new_capacity); - mutex_unlock(&cpu_scale_mutex); - } - - return count; -} - -static DEVICE_ATTR_RW(cpu_capacity); - -static int register_cpu_capacity_sysctl(void) -{ - int i; - struct device *cpu; - - for_each_possible_cpu(i) { - cpu = get_cpu_device(i); - if (!cpu) { - pr_err("%s: too early to get CPU%d device!\n", - __func__, i); - continue; - } - device_create_file(cpu, &dev_attr_cpu_capacity); - } - - return 0; -} -subsys_initcall(register_cpu_capacity_sysctl); +extern unsigned long +arch_scale_cpu_capacity(struct sched_domain *sd, int cpu); +extern void set_capacity_scale(unsigned int cpu, unsigned long capacity); #ifdef CONFIG_OF struct cpu_efficiency { @@ -140,145 +75,9 @@ static unsigned long *__cpu_capacity; static unsigned long middle_capacity = 1; static bool cap_from_dt = true; -static u32 *raw_capacity; -static bool cap_parsing_failed; -static u32 capacity_scale; - -static int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) -{ - int ret = 1; - u32 cpu_capacity; - - if (cap_parsing_failed) - return !ret; - - ret = of_property_read_u32(cpu_node, - "capacity-dmips-mhz", - &cpu_capacity); - if (!ret) { - if (!raw_capacity) { - raw_capacity = kcalloc(num_possible_cpus(), - sizeof(*raw_capacity), - GFP_KERNEL); - if (!raw_capacity) { - pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); - cap_parsing_failed = true; - return ret; - } - } - capacity_scale = max(cpu_capacity, capacity_scale); - raw_capacity[cpu] = cpu_capacity; - pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n", - cpu_node->full_name, raw_capacity[cpu]); - } else { - if (raw_capacity) { - pr_err("cpu_capacity: missing %s raw capacity\n", - cpu_node->full_name); - pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); - } - cap_parsing_failed = true; - kfree(raw_capacity); - } - - return !ret; -} - -static void normalize_cpu_capacity(void) -{ - u64 capacity; - int cpu; - - if (!raw_capacity || cap_parsing_failed) - return; - - pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); - mutex_lock(&cpu_scale_mutex); - for_each_possible_cpu(cpu) { - capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) - / capacity_scale; - set_capacity_scale(cpu, capacity); - pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", - cpu, arch_scale_cpu_capacity(NULL, cpu)); - } - mutex_unlock(&cpu_scale_mutex); -} - -#ifdef CONFIG_CPU_FREQ -static cpumask_var_t cpus_to_visit; -static bool cap_parsing_done; -static void parsing_done_workfn(struct work_struct *work); -static DECLARE_WORK(parsing_done_work, parsing_done_workfn); - -static int -init_cpu_capacity_callback(struct notifier_block *nb, - unsigned long val, - void *data) -{ - struct cpufreq_policy *policy = data; - int cpu; - - if (cap_parsing_failed || cap_parsing_done) - return 0; - - switch (val) { - case CPUFREQ_NOTIFY: - pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", - cpumask_pr_args(policy->related_cpus), - cpumask_pr_args(cpus_to_visit)); - cpumask_andnot(cpus_to_visit, - cpus_to_visit, - policy->related_cpus); - for_each_cpu(cpu, policy->related_cpus) { - raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) * - policy->cpuinfo.max_freq / 1000UL; - capacity_scale = max(raw_capacity[cpu], capacity_scale); - } - if (cpumask_empty(cpus_to_visit)) { - normalize_cpu_capacity(); - kfree(raw_capacity); - pr_debug("cpu_capacity: parsing done\n"); - cap_parsing_done = true; - schedule_work(&parsing_done_work); - } - } - return 0; -} - -static struct notifier_block init_cpu_capacity_notifier = { - .notifier_call = init_cpu_capacity_callback, -}; - -static int __init register_cpufreq_notifier(void) -{ - if (cap_parsing_failed) - return -EINVAL; - - if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { - pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); - return -ENOMEM; - } - cpumask_copy(cpus_to_visit, cpu_possible_mask); - - return cpufreq_register_notifier(&init_cpu_capacity_notifier, - CPUFREQ_POLICY_NOTIFIER); -} -core_initcall(register_cpufreq_notifier); - -static void parsing_done_workfn(struct work_struct *work) -{ - cpufreq_unregister_notifier(&init_cpu_capacity_notifier, - CPUFREQ_POLICY_NOTIFIER); -} - -#else -static int __init free_raw_capacity(void) -{ - kfree(raw_capacity); - - return 0; -} -core_initcall(free_raw_capacity); -#endif +extern bool cap_parsing_failed; +extern void normalize_cpu_capacity(void); +extern int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu); /* * Iterate all CPUs' descriptor in DT and compute the efficiency diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 111742126897..7534bb41ee09 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -36,6 +36,7 @@ config ARM64 select EDAC_SUPPORT select FRAME_POINTER select GENERIC_ALLOCATOR + select GENERIC_ARCH_TOPOLOGY select GENERIC_CLOCKEVENTS select GENERIC_CLOCKEVENTS_BROADCAST select GENERIC_CPU_AUTOPROBE diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 565dd69888cc..f629f7524d65 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -11,7 +11,6 @@ * for more details. */ -#include <linux/acpi.h> #include <linux/cpu.h> #include <linux/cpumask.h> #include <linux/init.h> @@ -22,226 +21,14 @@ #include <linux/sched.h> #include <linux/slab.h> #include <linux/string.h> -#include <linux/cpufreq.h> #include <asm/cpu.h> #include <asm/cputype.h> #include <asm/topology.h> -static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; -static DEFINE_MUTEX(cpu_scale_mutex); - -unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) -{ - return per_cpu(cpu_scale, cpu); -} - -static void set_capacity_scale(unsigned int cpu, unsigned long capacity) -{ - per_cpu(cpu_scale, cpu) = capacity; -} - -static ssize_t cpu_capacity_show(struct device *dev, - struct device_attribute *attr, - char *buf) -{ - struct cpu *cpu = container_of(dev, struct cpu, dev); - - return sprintf(buf, "%lu\n", - arch_scale_cpu_capacity(NULL, cpu->dev.id)); -} - -static ssize_t cpu_capacity_store(struct device *dev, - struct device_attribute *attr, - const char *buf, - size_t count) -{ - struct cpu *cpu = container_of(dev, struct cpu, dev); - int this_cpu = cpu->dev.id, i; - unsigned long new_capacity; - ssize_t ret; - - if (count) { - ret = kstrtoul(buf, 0, &new_capacity); - if (ret) - return ret; - if (new_capacity > SCHED_CAPACITY_SCALE) - return -EINVAL; - - mutex_lock(&cpu_scale_mutex); - for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) - set_capacity_scale(i, new_capacity); - mutex_unlock(&cpu_scale_mutex); - } - - return count; -} - -static DEVICE_ATTR_RW(cpu_capacity); - -static int register_cpu_capacity_sysctl(void) -{ - int i; - struct device *cpu; - - for_each_possible_cpu(i) { - cpu = get_cpu_device(i); - if (!cpu) { - pr_err("%s: too early to get CPU%d device!\n", - __func__, i); - continue; - } - device_create_file(cpu, &dev_attr_cpu_capacity); - } - - return 0; -} -subsys_initcall(register_cpu_capacity_sysctl); - -static u32 capacity_scale; -static u32 *raw_capacity; -static bool cap_parsing_failed; - -static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) -{ - int ret; - u32 cpu_capacity; - - if (cap_parsing_failed) - return; - - ret = of_property_read_u32(cpu_node, - "capacity-dmips-mhz", - &cpu_capacity); - if (!ret) { - if (!raw_capacity) { - raw_capacity = kcalloc(num_possible_cpus(), - sizeof(*raw_capacity), - GFP_KERNEL); - if (!raw_capacity) { - pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); - cap_parsing_failed = true; - return; - } - } - capacity_scale = max(cpu_capacity, capacity_scale); - raw_capacity[cpu] = cpu_capacity; - pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n", - cpu_node->full_name, raw_capacity[cpu]); - } else { - if (raw_capacity) { - pr_err("cpu_capacity: missing %s raw capacity\n", - cpu_node->full_name); - pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); - } - cap_parsing_failed = true; - kfree(raw_capacity); - } -} - -static void normalize_cpu_capacity(void) -{ - u64 capacity; - int cpu; - - if (!raw_capacity || cap_parsing_failed) - return; - - pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); - mutex_lock(&cpu_scale_mutex); - for_each_possible_cpu(cpu) { - pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", - cpu, raw_capacity[cpu]); - capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) - / capacity_scale; - set_capacity_scale(cpu, capacity); - pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", - cpu, arch_scale_cpu_capacity(NULL, cpu)); - } - mutex_unlock(&cpu_scale_mutex); -} - -#ifdef CONFIG_CPU_FREQ -static cpumask_var_t cpus_to_visit; -static bool cap_parsing_done; -static void parsing_done_workfn(struct work_struct *work); -static DECLARE_WORK(parsing_done_work, parsing_done_workfn); - -static int -init_cpu_capacity_callback(struct notifier_block *nb, - unsigned long val, - void *data) -{ - struct cpufreq_policy *policy = data; - int cpu; - - if (cap_parsing_failed || cap_parsing_done) - return 0; - - switch (val) { - case CPUFREQ_NOTIFY: - pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", - cpumask_pr_args(policy->related_cpus), - cpumask_pr_args(cpus_to_visit)); - cpumask_andnot(cpus_to_visit, - cpus_to_visit, - policy->related_cpus); - for_each_cpu(cpu, policy->related_cpus) { - raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) * - policy->cpuinfo.max_freq / 1000UL; - capacity_scale = max(raw_capacity[cpu], capacity_scale); - } - if (cpumask_empty(cpus_to_visit)) { - normalize_cpu_capacity(); - kfree(raw_capacity); - pr_debug("cpu_capacity: parsing done\n"); - cap_parsing_done = true; - schedule_work(&parsing_done_work); - } - } - return 0; -} - -static struct notifier_block init_cpu_capacity_notifier = { - .notifier_call = init_cpu_capacity_callback, -}; - -static int __init register_cpufreq_notifier(void) -{ - /* - * on ACPI-based systems we need to use the default cpu capacity - * until we have the necessary code to parse the cpu capacity, so - * skip registering cpufreq notifier. - */ - if (!acpi_disabled || cap_parsing_failed) - return -EINVAL; - - if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { - pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); - return -ENOMEM; - } - cpumask_copy(cpus_to_visit, cpu_possible_mask); - - return cpufreq_register_notifier(&init_cpu_capacity_notifier, - CPUFREQ_POLICY_NOTIFIER); -} -core_initcall(register_cpufreq_notifier); - -static void parsing_done_workfn(struct work_struct *work) -{ - cpufreq_unregister_notifier(&init_cpu_capacity_notifier, - CPUFREQ_POLICY_NOTIFIER); -} - -#else -static int __init free_raw_capacity(void) -{ - kfree(raw_capacity); - - return 0; -} -core_initcall(free_raw_capacity); -#endif +extern bool cap_parsing_failed; +extern void normalize_cpu_capacity(void); +extern int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu); static int __init get_cpu_for_node(struct device_node *node) { diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index d718ae4b907a..307ea31187dd 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -339,4 +339,12 @@ config CMA_ALIGNMENT endif +config GENERIC_ARCH_TOPOLOGY + bool + help + Enable support for architectures common topology code: e.g., parsing + CPU capacity information from DT, usage of such information for + appropriate scaling, sysfs interface for changing capacity values at + runtime. + endmenu diff --git a/drivers/base/Makefile b/drivers/base/Makefile index f2816f6ff76a..397e5c344e6a 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -23,6 +23,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o obj-$(CONFIG_PINCTRL) += pinctrl.o obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o +obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o obj-y += test/ diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c new file mode 100644 index 000000000000..c1dd430adad2 --- /dev/null +++ b/drivers/base/arch_topology.c @@ -0,0 +1,237 @@ +/* + * driver/base/arch_topology.c - Arch specific cpu topology information + * + * Copyright (C) 2016, ARM Ltd. + * Written by: Juri Lelli, ARM Ltd. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/acpi.h> +#include <linux/cpu.h> +#include <linux/cpufreq.h> +#include <linux/device.h> +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/topology.h> + +static DEFINE_MUTEX(cpu_scale_mutex); +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; + +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) +{ + return per_cpu(cpu_scale, cpu); +} + +void set_capacity_scale(unsigned int cpu, unsigned long capacity) +{ + per_cpu(cpu_scale, cpu) = capacity; +} + +static ssize_t cpu_capacity_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + + return sprintf(buf, "%lu\n", + arch_scale_cpu_capacity(NULL, cpu->dev.id)); +} + +static ssize_t cpu_capacity_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t count) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + int this_cpu = cpu->dev.id, i; + unsigned long new_capacity; + ssize_t ret; + + if (count) { + ret = kstrtoul(buf, 0, &new_capacity); + if (ret) + return ret; + if (new_capacity > SCHED_CAPACITY_SCALE) + return -EINVAL; + + mutex_lock(&cpu_scale_mutex); + for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) + set_capacity_scale(i, new_capacity); + mutex_unlock(&cpu_scale_mutex); + } + + return count; +} + +static DEVICE_ATTR_RW(cpu_capacity); + +static int register_cpu_capacity_sysctl(void) +{ + int i; + struct device *cpu; + + for_each_possible_cpu(i) { + cpu = get_cpu_device(i); + if (!cpu) { + pr_err("%s: too early to get CPU%d device!\n", + __func__, i); + continue; + } + device_create_file(cpu, &dev_attr_cpu_capacity); + } + + return 0; +} +subsys_initcall(register_cpu_capacity_sysctl); + +u32 capacity_scale; +u32 *raw_capacity; +bool cap_parsing_failed; + +void normalize_cpu_capacity(void) +{ + u64 capacity; + int cpu; + + if (!raw_capacity || cap_parsing_failed) + return; + + pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale); + mutex_lock(&cpu_scale_mutex); + for_each_possible_cpu(cpu) { + pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n", + cpu, raw_capacity[cpu]); + capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) + / capacity_scale; + set_capacity_scale(cpu, capacity); + pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", + cpu, arch_scale_cpu_capacity(NULL, cpu)); + } + mutex_unlock(&cpu_scale_mutex); +} + +int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) +{ + int ret = 1; + u32 cpu_capacity; + + if (cap_parsing_failed) + return !ret; + + ret = of_property_read_u32(cpu_node, + "capacity-dmips-mhz", + &cpu_capacity); + if (!ret) { + if (!raw_capacity) { + raw_capacity = kcalloc(num_possible_cpus(), + sizeof(*raw_capacity), + GFP_KERNEL); + if (!raw_capacity) { + pr_err("cpu_capacity: failed to allocate memory for raw capacities\n"); + cap_parsing_failed = true; + return ret; + } + } + capacity_scale = max(cpu_capacity, capacity_scale); + raw_capacity[cpu] = cpu_capacity; + pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n", + cpu_node->full_name, raw_capacity[cpu]); + } else { + if (raw_capacity) { + pr_err("cpu_capacity: missing %s raw capacity\n", + cpu_node->full_name); + pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); + } + cap_parsing_failed = true; + kfree(raw_capacity); + } + + return !ret; +} + +#ifdef CONFIG_CPU_FREQ +static cpumask_var_t cpus_to_visit; +static bool cap_parsing_done; +static void parsing_done_workfn(struct work_struct *work); +static DECLARE_WORK(parsing_done_work, parsing_done_workfn); + +static int +init_cpu_capacity_callback(struct notifier_block *nb, + unsigned long val, + void *data) +{ + struct cpufreq_policy *policy = data; + int cpu; + + if (cap_parsing_failed || cap_parsing_done) + return 0; + + switch (val) { + case CPUFREQ_NOTIFY: + pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n", + cpumask_pr_args(policy->related_cpus), + cpumask_pr_args(cpus_to_visit)); + cpumask_andnot(cpus_to_visit, + cpus_to_visit, + policy->related_cpus); + for_each_cpu(cpu, policy->related_cpus) { + raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) * + policy->cpuinfo.max_freq / 1000UL; + capacity_scale = max(raw_capacity[cpu], capacity_scale); + } + if (cpumask_empty(cpus_to_visit)) { + normalize_cpu_capacity(); + kfree(raw_capacity); + pr_debug("cpu_capacity: parsing done\n"); + cap_parsing_done = true; + schedule_work(&parsing_done_work); + } + } + return 0; +} + +static struct notifier_block init_cpu_capacity_notifier = { + .notifier_call = init_cpu_capacity_callback, +}; + +static int __init register_cpufreq_notifier(void) +{ + /* + * on ACPI-based systems we need to use the default cpu capacity + * until we have the necessary code to parse the cpu capacity, so + * skip registering cpufreq notifier. + */ + if (!acpi_disabled || cap_parsing_failed) + return -EINVAL; + + if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) { + pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n"); + return -ENOMEM; + } + + cpumask_copy(cpus_to_visit, cpu_possible_mask); + + return cpufreq_register_notifier(&init_cpu_capacity_notifier, + CPUFREQ_POLICY_NOTIFIER); +} +core_initcall(register_cpufreq_notifier); + +static void parsing_done_workfn(struct work_struct *work) +{ + cpufreq_unregister_notifier(&init_cpu_capacity_notifier, + CPUFREQ_POLICY_NOTIFIER); +} + +#else +static int __init free_raw_capacity(void) +{ + kfree(raw_capacity); + + return 0; +} +core_initcall(free_raw_capacity); +#endif
arm and arm64 share lot of code relative to parsing CPU capacity information from DT, using that information for appropriate scaling and exposing a sysfs interface for chaging such values at runtime. Factorize such code in a common place (driver/base/arch_topology.c) in preparation for further additions. Suggested-by: Will Deacon <will.deacon@arm.com> Suggested-by: Mark Rutland <mark.rutland@arm.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Juri Lelli <juri.lelli@arm.com> --- Changes from v1: - keep the original GPLv2 header --- arch/arm/Kconfig | 1 + arch/arm/kernel/topology.c | 213 ++------------------------------------ arch/arm64/Kconfig | 1 + arch/arm64/kernel/topology.c | 219 +-------------------------------------- drivers/base/Kconfig | 8 ++ drivers/base/Makefile | 1 + drivers/base/arch_topology.c | 237 +++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 257 insertions(+), 423 deletions(-) create mode 100644 drivers/base/arch_topology.c