From 70b8301f6b8f7bc053377a9cbd0c4e42e29d9807 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 19 May 2016 17:09:55 -0700 Subject: x86/topology: Add topology_max_smt_threads() For SMT specific workarounds it is useful to know if SMT is active on any online CPU in the system. This currently requires a loop over all online CPUs. Add a global variable that is updated with the maximum number of smt threads on any CPU on online/offline, and use it for topology_max_smt_threads() The single call is easier to use than a loop. Not exported to user space because user space already can use the existing sibling interfaces to find this out. Signed-off-by: Andi Kleen Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Cc: jolsa@kernel.org Link: http://lkml.kernel.org/r/1463703002-19686-2-git-send-email-andi@firstfloor.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/topology.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 7f991bd5031b..e346572841a0 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -129,6 +129,14 @@ extern const struct cpumask *cpu_coregroup_mask(int cpu); extern unsigned int __max_logical_packages; #define topology_max_packages() (__max_logical_packages) + +extern int __max_smt_threads; + +static inline int topology_max_smt_threads(void) +{ + return __max_smt_threads; +} + int topology_update_package_map(unsigned int apicid, unsigned int cpu); extern int topology_phys_to_logical_pkg(unsigned int pkg); #else @@ -136,6 +144,7 @@ extern int topology_phys_to_logical_pkg(unsigned int pkg); static inline int topology_update_package_map(unsigned int apicid, unsigned int cpu) { return 0; } static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; } +static inline int topology_max_smt_threads(void) { return 1; } #endif static inline void arch_fix_phys_package_id(int num, u32 slot) -- cgit v1.2.3