[PATCH] topology: Provide CPU topology in sysfs in !SMP configurations

[PATCH] topology: Provide CPU topology in sysfs in !SMP configurations

[Ben Hutchings]

We should provide topology information to userland even if it's not
very interesting.  The current code appears to work properly for !SMP
(tested on i386).

Reference: http://bugs.debian.org/649216
Reported-by: Marcus Osdoba <marcus.osdoba@googlemail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/base/Makefile |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 99a375a..1334d89 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -3,7 +3,8 @@
 obj-y			:= core.o sys.o bus.o dd.o syscore.o \
 			   driver.o class.o platform.o \
 			   cpu.o firmware.o init.o map.o devres.o \
-			   attribute_container.o transport_class.o
+			   attribute_container.o transport_class.o \
+			   topology.o
 obj-$(CONFIG_DEVTMPFS)	+= devtmpfs.o
 obj-y			+= power/
 obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
@@ -12,7 +13,6 @@ obj-$(CONFIG_ISA)	+= isa.o
 obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)	+= node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
-obj-$(CONFIG_SMP)	+= topology.o
 ifeq ($(CONFIG_SYSFS),y)
 obj-$(CONFIG_MODULES)	+= module.o
 endif
-- 
1.7.7.3

Re: [PATCH] topology: Provide CPU topology in sysfs in !SMP configurations

[Greg KH]

On Thu, Nov 24, 2011 at 07:04:39AM +0000, Ben Hutchings wrote:
> We should provide topology information to userland even if it's not
> very interesting.  The current code appears to work properly for !SMP
> (tested on i386).

Why, what will the topology look like for this?

thanks,

greg k-h

Re: [PATCH] topology: Provide CPU topology in sysfs in !SMP configurations

[Ben Hutchings]

On Thu, Nov 24, 2011 at 08:24:26AM -0800, Greg KH wrote:
> On Thu, Nov 24, 2011 at 07:04:39AM +0000, Ben Hutchings wrote:
> > We should provide topology information to userland even if it's not
> > very interesting.  The current code appears to work properly for !SMP
> > (tested on i386).
> 
> Why, what will the topology look like for this?
 
physical_package_id: "-1"
core_id: "0"
thread_siblings: "1"
thread_siblings_list: "0"
core_siblings: "1"
core_siblings_list: "0"

Ben.

-- 
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
                                                              - Albert Camus

Re: [PATCH] topology: Provide CPU topology in sysfs in !SMP configurations

[Geert Uytterhoeven]

On Thu, Nov 24, 2011 at 08:04, Ben Hutchings <ben@decadent.org.uk> wrote:
> We should provide topology information to userland even if it's not
> very interesting.  The current code appears to work properly for !SMP
> (tested on i386).
>
> Reference: http://bugs.debian.org/649216
> Reported-by: Marcus Osdoba <marcus.osdoba@googlemail.com>
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> ---
>  drivers/base/Makefile |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/Makefile b/drivers/base/Makefile
> index 99a375a..1334d89 100644
> --- a/drivers/base/Makefile
> +++ b/drivers/base/Makefile
> @@ -3,7 +3,8 @@
>  obj-y                  := core.o sys.o bus.o dd.o syscore.o \
>                           driver.o class.o platform.o \
>                           cpu.o firmware.o init.o map.o devres.o \
> -                          attribute_container.o transport_class.o
> +                          attribute_container.o transport_class.o \
> +                          topology.o
>  obj-$(CONFIG_DEVTMPFS) += devtmpfs.o
>  obj-y                  += power/
>  obj-$(CONFIG_HAS_DMA)  += dma-mapping.o
> @@ -12,7 +13,6 @@ obj-$(CONFIG_ISA)     += isa.o
>  obj-$(CONFIG_FW_LOADER)        += firmware_class.o
>  obj-$(CONFIG_NUMA)     += node.o
>  obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
> -obj-$(CONFIG_SMP)      += topology.o
>  ifeq ($(CONFIG_SYSFS),y)
>  obj-$(CONFIG_MODULES)  += module.o
>  endif

Taking this to linux-arch with a follow up from Ben due to crashes
reported on the
debian-m68k mailing list:

> > My guess is that on m68k get_cpu_sysdev(0) returns NULL and thus
> > topology_add_dev() passes an invalid pointer into sysfs_create_group().
> > So either m68k (and maybe some other architectures with no SMP support)
> > need to be fixed or the CPU topology code needs to allow for this.
>
> None of these architectures appears to call register_cpu():
>
>    c6x frv h8300 m68k microblaze openrisc score um xtensa
>
> and therefore they will all panic at boot following this change (commit
> ccbc60d3e19a1b6ae66ca0d89b3da02dde62088b).  So either I can try to fix
> them or else it must be reverted for now.

The commit mentioned above is in linux-next (and in Debian's 3.2-rc7).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds