[PATCH v3 0/2] Move x86_cpu_to_apicid to the __read_mostly section

Vlad Zolotarov
2012-05-20T15:19:16Z

Pls., consider applying this patch series.
It contains the following changes:
- Adds two new macros DEFINE_EARLY_PER_CPU_READ_MOSTLY() and
DECLARE_EARLY_PER_CPU_READ_MOSTLY().
- Adds "read-mostly" qualifier to the following variables in smp.h:
- cpu_sibling_map
- cpu_core_map
- cpu_llc_shared_map
- cpu_llc_id
- cpu_number
- x86_cpu_to_apicid
- x86_bios_cpu_apicid
- x86_cpu_to_logical_apicid

As long as all the variables above are only written during the initialization,
this change is meant to prevent the false sharing and improve the
performance on large multiprocessor systems.

v3 changes:
- Added the missing definitions of DEFINE_EARLY_PER_CPU_READ_MOSTLY()
and DECLARE_EARLY_PER_CPU_READ_MOSTLY() macros in the !CONFIG_SMP code
path in arch/x86/include/asm/percpu.h.

thanks,
vlad