x86/intel_rdt: Add scheduler hook

[linux-2.6-microblaze.git] / arch / x86 / include / asm / intel_rdt.h

diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index 2e5eab0..5bc72a4 100644 (file)
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -1,8 +1,12 @@
 #ifndef _ASM_X86_INTEL_RDT_H
 #define _ASM_X86_INTEL_RDT_H
 
+#ifdef CONFIG_INTEL_RDT_A
+
 #include <linux/jump_label.h>
 
+#include <asm/intel_rdt_common.h>
+
 #define IA32_L3_QOS_CFG                0xc81
 #define IA32_L3_CBM_BASE       0xc90
 #define IA32_L2_CBM_BASE       0xd10
@@ -176,4 +180,42 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
                                char *buf, size_t nbytes, loff_t off);
 int rdtgroup_schemata_show(struct kernfs_open_file *of,
                           struct seq_file *s, void *v);
+
+/*
+ * intel_rdt_sched_in() - Writes the task's CLOSid 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.
+ */
+static inline void intel_rdt_sched_in(void)
+{
+       if (static_branch_likely(&rdt_enable_key)) {
+               struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
+               int 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(cpu_closid);
+
+               if (closid != state->closid) {
+                       state->closid = closid;
+                       wrmsr(MSR_IA32_PQR_ASSOC, state->rmid, closid);
+               }
+       }
+}
+
+#else
+
+static inline void intel_rdt_sched_in(void) {}
+
+#endif /* CONFIG_INTEL_RDT_A */
 #endif /* _ASM_X86_INTEL_RDT_H */