powercap/rapl: reduce ipi calls

Reduce remote CPU calls for MSR access by combining read
modify write into one function.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 85 insertions, 34 deletions

diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
index 6c592dc71aee..a50e644ae07a 100644
--- a/drivers/powercap/intel_rapl.c
+++ b/drivers/powercap/intel_rapl.c
@@ -133,6 +133,12 @@ struct rapl_domain_data {
         unsigned long timestamp;
 };
 
+struct msrl_action {
+        u32 msr_no;
+        u64 clear_mask;
+        u64 set_mask;
+        int err;
+};
 
 #define DOMAIN_STATE_INACTIVE           BIT(0)
 #define DOMAIN_STATE_POWER_LIMIT_SET    BIT(1)
@@ -800,35 +806,62 @@ static int rapl_read_data_raw(struct rapl_domain *rd,
         return 0;
 }
 
+
+static int msrl_update_safe(u32 msr_no, u64 clear_mask, u64 set_mask)
+{
+        int err;
+        u64 val;
+
+        err = rdmsrl_safe(msr_no, &val);
+        if (err)
+                goto out;
+
+        val &= ~clear_mask;
+        val |= set_mask;
+
+        err = wrmsrl_safe(msr_no, val);
+
+out:
+        return err;
+}
+
+static void msrl_update_func(void *info)
+{
+        struct msrl_action *ma = info;
+
+        ma->err = msrl_update_safe(ma->msr_no, ma->clear_mask, ma->set_mask);
+}
+
 /* Similar use of primitive info in the read counterpart */
 static int rapl_write_data_raw(struct rapl_domain *rd,
                         enum rapl_primitives prim,
                         unsigned long long value)
 {
-        u64 msr_val;
-        u32 msr;
         struct rapl_primitive_info *rp = &rpi[prim];
         int cpu;
+        u64 bits;
+        struct msrl_action ma;
+        int ret;
 
         cpu = find_active_cpu_on_package(rd->package_id);
         if (cpu < 0)
                 return cpu;
-        msr = rd->msrs[rp->id];
-        if (rdmsrl_safe_on_cpu(cpu, msr, &msr_val)) {
-                dev_dbg(&rd->power_zone.dev,
-                        "failed to read msr 0x%x on cpu %d\n", msr, cpu);
-                return -EIO;
-        }
-        value = rapl_unit_xlate(rd, rd->package_id, rp->unit, value, 1);
-        msr_val &= ~rp->mask;
-        msr_val |= value << rp->shift;
-        if (wrmsrl_safe_on_cpu(cpu, msr, msr_val)) {
-                dev_dbg(&rd->power_zone.dev,
-                        "failed to write msr 0x%x on cpu %d\n", msr, cpu);
-                return -EIO;
-        }
 
-        return 0;
+        bits = rapl_unit_xlate(rd, rd->package_id, rp->unit, value, 1);
+        bits |= bits << rp->shift;
+        memset(&ma, 0, sizeof(ma));
+
+        ma.msr_no = rd->msrs[rp->id];
+        ma.clear_mask = rp->mask;
+        ma.set_mask = bits;
+
+        ret = smp_call_function_single(cpu, msrl_update_func, &ma, 1);
+        if (ret)
+                WARN_ON_ONCE(ret);
+        else
+                ret = ma.err;
+
+        return ret;
 }
 
 /*
@@ -893,6 +926,21 @@ static int rapl_check_unit_atom(struct rapl_package *rp, int cpu)
         return 0;
 }
 
+static void power_limit_irq_save_cpu(void *info)
+{
+        u32 l, h = 0;
+        struct rapl_package *rp = (struct rapl_package *)info;
+
+        /* save the state of PLN irq mask bit before disabling it */
+        rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);
+        if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED)) {
+                rp->power_limit_irq = l & PACKAGE_THERM_INT_PLN_ENABLE;
+                rp->power_limit_irq |= PACKAGE_PLN_INT_SAVED;
+        }
+        l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
+        wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+}
+
 
 /* REVISIT:
  * When package power limit is set artificially low by RAPL, LVT
@@ -906,7 +954,6 @@ static int rapl_check_unit_atom(struct rapl_package *rp, int cpu)
 
 static void package_power_limit_irq_save(int package_id)
 {
-        u32 l, h = 0;
         int cpu;
         struct rapl_package *rp;
 
@@ -920,20 +967,30 @@ static void package_power_limit_irq_save(int package_id)
         cpu = find_active_cpu_on_package(package_id);
         if (cpu < 0)
                 return;
-        /* save the state of PLN irq mask bit before disabling it */
-        rdmsr_safe_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);
-        if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED)) {
-                rp->power_limit_irq = l & PACKAGE_THERM_INT_PLN_ENABLE;
-                rp->power_limit_irq |= PACKAGE_PLN_INT_SAVED;
-        }
-        l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
-        wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+        if (!boot_cpu_has(X86_FEATURE_PTS) || !boot_cpu_has(X86_FEATURE_PLN))
+                return;
+
+        smp_call_function_single(cpu, power_limit_irq_save_cpu, rp, 1);
+}
+
+static void power_limit_irq_restore_cpu(void *info)
+{
+        u32 l, h = 0;
+        struct rapl_package *rp = (struct rapl_package *)info;
+
+        rdmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);
+
+        if (rp->power_limit_irq & PACKAGE_THERM_INT_PLN_ENABLE)
+                l |= PACKAGE_THERM_INT_PLN_ENABLE;
+        else
+                l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
+
+        wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
 }
 
 /* restore per package power limit interrupt enable state */
 static void package_power_limit_irq_restore(int package_id)
 {
-        u32 l, h;
         int cpu;
         struct rapl_package *rp;
 
@@ -951,14 +1008,8 @@ static void package_power_limit_irq_restore(int package_id)
         /* irq enable state not saved, nothing to restore */
         if (!(rp->power_limit_irq & PACKAGE_PLN_INT_SAVED))
                 return;
-        rdmsr_safe_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, &l, &h);
-
-        if (rp->power_limit_irq & PACKAGE_THERM_INT_PLN_ENABLE)
-                l |= PACKAGE_THERM_INT_PLN_ENABLE;
-        else
-                l &= ~PACKAGE_THERM_INT_PLN_ENABLE;
 
-        wrmsr_on_cpu(cpu, MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
+        smp_call_function_single(cpu, power_limit_irq_restore_cpu, rp, 1);
 }
 
 static void set_floor_freq_default(struct rapl_domain *rd, bool mode)