Commit-ID: 748b6b881ccdda8f0663c68605f431279e06f49a Gitweb: http://git.kernel.org/tip/748b6b881ccdda8f0663c68605f431279e06f49a Author: Vikas Shivappa <vikas.shiva...@linux.intel.com> AuthorDate: Tue, 25 Jul 2017 14:14:43 -0700 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Tue, 1 Aug 2017 22:41:28 +0200
x86/intel_rdt/cqm: Add sched_in support OS associates an RMID/CLOSid to a task by writing the per CPU IA32_PQR_ASSOC MSR when a task is scheduled in. The sched_in code will stay as no-op unless we are running on Intel SKU which supports either resource control or monitoring and we also enable them by mounting the resctrl fs. The per cpu CLOSid/RMID values are cached and the write is performed only when a task with a different CLOSid/RMID is scheduled in. Signed-off-by: Vikas Shivappa <vikas.shiva...@linux.intel.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: ravi.v.shan...@intel.com Cc: tony.l...@intel.com Cc: fenghua...@intel.com Cc: pet...@infradead.org Cc: eran...@google.com Cc: vikas.shiva...@intel.com Cc: a...@linux.intel.com Cc: davi...@google.com Cc: reinette.cha...@intel.com Link: http://lkml.kernel.org/r/1501017287-28083-25-git-send-email-vikas.shiva...@linux.intel.com --- arch/x86/include/asm/intel_rdt_sched.h | 50 ++++++++++++++++++++-------------- arch/x86/kernel/cpu/intel_rdt.h | 4 --- 2 files changed, 29 insertions(+), 25 deletions(-) diff --git a/arch/x86/include/asm/intel_rdt_sched.h b/arch/x86/include/asm/intel_rdt_sched.h index 8c5be01..3badc0a 100644 --- a/arch/x86/include/asm/intel_rdt_sched.h +++ b/arch/x86/include/asm/intel_rdt_sched.h @@ -15,7 +15,8 @@ * * The upper 32 bits of IA32_PQR_ASSOC contain closid and the * lower 10 bits rmid. The update to IA32_PQR_ASSOC always - * contains both parts, so we need to cache them. + * contains both parts, so we need to cache them. This also + * stores the user configured per cpu CLOSID and RMID. * * The cache also helps to avoid pointless updates if the value does * not change. @@ -30,38 +31,45 @@ DECLARE_PER_CPU_READ_MOSTLY(struct intel_pqr_state, rdt_cpu_default); DECLARE_STATIC_KEY_FALSE(rdt_enable_key); DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key); +DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); /* - * __intel_rdt_sched_in() - Writes the task's CLOSid to IA32_PQR_MSR + * __intel_rdt_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR * * Following considerations are made so that this has minimal impact * on scheduler hot path: * - This will stay as no-op unless we are running on an Intel SKU - * which supports resource control and we enable by mounting the - * resctrl file system. - * - Caches the per cpu CLOSid values and does the MSR write only - * when a task with a different CLOSid is scheduled in. - * + * which supports resource control or monitoring and we enable by + * mounting the resctrl file system. + * - Caches the per cpu CLOSid/RMID values and does the MSR write only + * when a task with a different CLOSid/RMID is scheduled in. + * - We allocate RMIDs/CLOSids globally in order to keep this as + * simple as possible. * Must be called with preemption disabled. */ -static inline void __intel_rdt_sched_in(void) +static void __intel_rdt_sched_in(void) { + struct intel_pqr_state newstate = this_cpu_read(rdt_cpu_default); + struct intel_pqr_state *curstate = this_cpu_ptr(&pqr_state); + + /* + * If this task has a closid/rmid assigned, use it. + * Else use the closid/rmid assigned to this cpu. + */ if (static_branch_likely(&rdt_alloc_enable_key)) { - struct intel_pqr_state *state = this_cpu_ptr(&pqr_state); - u32 closid; + if (current->closid) + newstate.closid = current->closid; + } - /* - * If this task has a closid assigned, use it. - * Else use the closid assigned to this cpu. - */ - closid = current->closid; - if (closid == 0) - closid = this_cpu_read(rdt_cpu_default.closid); + if (static_branch_likely(&rdt_mon_enable_key)) { + if (current->rmid) + newstate.rmid = current->rmid; + } - if (closid != state->closid) { - state->closid = closid; - wrmsr(IA32_PQR_ASSOC, state->rmid, closid); - } + if (newstate.closid != curstate->closid || + newstate.rmid != curstate->rmid) { + *curstate = newstate; + wrmsr(IA32_PQR_ASSOC, newstate.rmid, newstate.closid); } } diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h index 92a5d30..7fcaa5f 100644 --- a/arch/x86/kernel/cpu/intel_rdt.h +++ b/arch/x86/kernel/cpu/intel_rdt.h @@ -22,8 +22,6 @@ #define RMID_VAL_ERROR BIT_ULL(63) #define RMID_VAL_UNAVAIL BIT_ULL(62) -DECLARE_STATIC_KEY_FALSE(rdt_enable_key); - /** * struct mon_evt - Entry in the event list of a resource * @evtid: event id @@ -61,8 +59,6 @@ extern bool rdt_alloc_capable; extern bool rdt_mon_capable; extern unsigned int rdt_mon_features; -DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); - enum rdt_group_type { RDTCTRL_GROUP = 0, RDTMON_GROUP,
