On Sun, 2 Jul 2017, Thomas Gleixner wrote:
On Mon, 26 Jun 2017, Vikas Shivappa wrote:
DECLARE_PER_CPU(struct intel_pqr_state, pqr_state);
DECLARE_PER_CPU_READ_MOSTLY(int, cpu_closid);
+DECLARE_PER_CPU_READ_MOSTLY(int, cpu_rmid);
DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
+DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
+DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
Please make this a two stage change. Add rdt_enable_key first and then the
monitoring stuff. Ideally you introduce rdt_enable_key here and in the
control code in one go.
+static void __intel_rdt_sched_in(void)
{
- if (static_branch_likely(&rdt_alloc_enable_key)) {
- struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
- int closid;
+ struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
+ u32 closid = 0;
+ u32 rmid = 0;
+ if (static_branch_likely(&rdt_alloc_enable_key)) {
/*
* If this task has a closid assigned, use it.
* Else use the closid assigned to this cpu.
@@ -55,14 +59,31 @@ static inline void intel_rdt_sched_in(void)
closid = current->closid;
if (closid == 0)
closid = this_cpu_read(cpu_closid);
+ }
+
+ if (static_branch_likely(&rdt_mon_enable_key)) {
+ /*
+ * If this task has a rmid assigned, use it.
+ * Else use the rmid assigned to this cpu.
+ */
+ rmid = current->rmid;
+ if (rmid == 0)
+ rmid = this_cpu_read(cpu_rmid);
+ }
- if (closid != state->closid) {
- state->closid = closid;
- wrmsr(IA32_PQR_ASSOC, state->rmid, closid);
- }
+ if (closid != state->closid || rmid != state->rmid) {
+ state->closid = closid;
+ state->rmid = rmid;
+ wrmsr(IA32_PQR_ASSOC, rmid, closid);
This can be written smarter.
struct intel_pqr_state newstate = this_cpu_read(rdt_cpu_default);
struct intel_pqr_state *curstate = this_cpu_ptr(&pqr_state);
if (static_branch_likely(&rdt_alloc_enable_key)) {
if (current->closid)
newstate.closid = current->closid;
}
if (static_branch_likely(&rdt_mon_enable_key)) {
if (current->rmid)
newstate.rmid = current->rmid;
}
if (newstate != *curstate) {
*curstate = newstate;
wrmsr(IA32_PQR_ASSOC, newstate.rmid, newstate.closid);
}
The unconditional read of rdt_cpu_default is the right thing to do because
the default behaviour is exactly this.
Ok makes sense. Will fix.
Thanks,
Vikas
Thanks,
tglx
