Messages in this thread | | | Date | Mon, 29 Nov 2021 07:53:54 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 1/3] topology/sysfs: export die attributes only if an architectures has support |
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On Sun, Nov 28, 2021 at 10:22:19PM +0100, Heiko Carstens wrote: > The die_id and die_cpus topology sysfs attributes have been added with > commit 0e344d8c709f ("cpu/topology: Export die_id") and commit > 2e4c54dac7b3 ("topology: Create core_cpus and die_cpus sysfs attributes"). > > While they are currently only used and useful for x86 they are still > present with bogus default values for all architectures. Instead of > enforcing such new sysfs attributes to all architectures, make them > only optional visible if an architecture opts in by defining both the > topology_die_id and topology_die_cpumask attributes. > > This is similar to what was done when the book and drawer topology > levels were introduced: avoid useless and therefore confusing sysfs > attributes for architectures which cannot make use of them. > > This should not break any existing applications, since this is a > rather new interface and applications should be able to handle also > older kernel versions without such attributes - besides that they > contain only useful information for x86. > > Signed-off-by: Heiko Carstens <hca@linux.ibm.com> > --- > Documentation/admin-guide/cputopology.rst | 3 +++ > drivers/base/topology.c | 8 ++++++++ > include/linux/topology.h | 2 ++ > 3 files changed, 13 insertions(+) > > diff --git a/Documentation/admin-guide/cputopology.rst b/Documentation/admin-guide/cputopology.rst > index 6b62e182baf4..c68d07533c45 100644 > --- a/Documentation/admin-guide/cputopology.rst > +++ b/Documentation/admin-guide/cputopology.rst > @@ -11,6 +11,9 @@ Architecture-neutral, drivers/base/topology.c, exports these attributes. > However, the book and drawer related sysfs files will only be created if > CONFIG_SCHED_BOOK and CONFIG_SCHED_DRAWER are selected, respectively. > > +The die hierarchy related sysfs files will only be created if an architecture > +provides the related macros as described below. > + > CONFIG_SCHED_BOOK and CONFIG_SCHED_DRAWER are currently only used on s390, > where they reflect the cpu and cache hierarchy. > > diff --git a/drivers/base/topology.c b/drivers/base/topology.c > index 8f2b641d0b8c..7fa5a7fbef25 100644 > --- a/drivers/base/topology.c > +++ b/drivers/base/topology.c > @@ -45,8 +45,10 @@ static ssize_t name##_list_read(struct file *file, struct kobject *kobj, \ > define_id_show_func(physical_package_id); > static DEVICE_ATTR_RO(physical_package_id); > > +#ifndef topology_die_no_sysfs
Please flip this #define around to be the other way: TOPOLOGY_DIE_SYSFS and enable/disable it.
Makes it much easier to understand than "negative logic"
Also, defines need to be all uppercase.
thanks,
greg k-h
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