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0816b0f036
Add "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. More specifically, on vSMP Foundation platform x86_cpu_to_apicid shared the same internode_cache_line with frequently written lapic_events. From the analysis of the first 33 per_cpu variables out of 219 (memories they describe, to be more specific) the 8 have read_mostly nature (tlb_vector_offset, cpu_loops_per_jiffy, xen_debug_irq, etc.) and 25 are frequently written (irq_stack_union, gdt_page, exception_stacks, idt_desc, etc.). Assuming that the spread of the rest of the per_cpu variables is similar, identifying the read mostly memories will make more sense in terms of long-term code maintenance comparing to identifying frequently written memories. Signed-off-by: Vlad Zolotarov <vlad@scalemp.com> Acked-by: Shai Fultheim <shai@scalemp.com> Cc: Shai Fultheim (Shai@ScaleMP.com) <Shai@scalemp.com> Cc: ido@wizery.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1719258.EYKzE4Zbq5@vlad Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| apic_flat_64.c | ||
| apic_noop.c | ||
| apic_numachip.c | ||
| apic.c | ||
| bigsmp_32.c | ||
| es7000_32.c | ||
| hw_nmi.c | ||
| io_apic.c | ||
| ipi.c | ||
| Makefile | ||
| numaq_32.c | ||
| probe_32.c | ||
| probe_64.c | ||
| summit_32.c | ||
| x2apic_cluster.c | ||
| x2apic_phys.c | ||
| x2apic_uv_x.c | ||