From 2ff799d3cff1ecb274049378b28120ee5c1c5e5f Mon Sep 17 00:00:00 2001 From: Vaidyanathan Srinivasan Date: Mon, 11 May 2009 20:09:14 +0530 Subject: [PATCH] sched: Don't export sched_mc_power_savings on multi-socket single core system Fix to prevent sched_mc_power_saving from being exported through sysfs for multi-scoket single core system. Max cores should be always greater than one (1). My earlier patch that introduced fix for not exporting 'sched_mc_power_saving' on laptops broke it on multi-socket single core system. This fix addresses issue on both laptop and multi-socket single core system. Below are the Test results: 1. Single socket - multi-core Before Patch: Does not export 'sched_mc_power_saving' After Patch: Does not export 'sched_mc_power_saving' Result: Pass 2. Multi Socket - single core Before Patch: exports 'sched_mc_power_saving' After Patch: Does not export 'sched_mc_power_saving' Result: Pass 3. Multi Socket - Multi core Before Patch: exports 'sched_mc_power_saving' After Patch: exports 'sched_mc_power_saving' [ Impact: make the sched_mc_power_saving control available more consistently ] Signed-off-by: Mahesh Salgaonkar Cc: Suresh B Siddha Cc: Venkatesh Pallipadi Cc: Peter Zijlstra LKML-Reference: <20090511143914.GB4853@dirshya.in.ibm.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/topology.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index f44b49abca49..066ef590d7e0 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -203,7 +203,8 @@ struct pci_bus; void x86_pci_root_bus_res_quirks(struct pci_bus *b); #ifdef CONFIG_SMP -#define mc_capable() (cpumask_weight(cpu_core_mask(0)) != nr_cpu_ids) +#define mc_capable() ((boot_cpu_data.x86_max_cores > 1) && \ + (cpumask_weight(cpu_core_mask(0)) != nr_cpu_ids)) #define smt_capable() (smp_num_siblings > 1) #endif -- 2.34.1