[RFC PATCH 05/20] x86/intel_rdt: make update_domains() learn the affected closids

From: James Morse
Date: Fri Aug 24 2018 - 06:46:14 EST


Now that the closid is present in the staged configuration,
update_domains() can learn which low/high values it should update.

Remove the single passed in closid, and update msr_param as we
apply each staged config.

Once the L2/L2CODE/L2DATA resources are merged this will allow
update_domains() to be called once for the single resource, even
when CDP is in use. This results in both CODE and DATA
configurations being applied and the two consecutive closids being
updated with a single smp_call_function_many().

This will let us keep the CDP odd/even behaviour inside resctrl
so that architectures that don't do this don't need to emulate it.

Signed-off-by: James Morse <james.morse@xxxxxxx>
---
arch/x86/kernel/cpu/intel_rdt.h | 4 ++--
arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 21 ++++++++++++++++-----
2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index 5e271e0fe1f5..8df549ef016d 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -241,8 +241,8 @@ static inline struct rdt_hw_domain *rc_dom_to_rdt(struct rdt_domain *r)
*/
struct msr_param {
struct rdt_resource *res;
- int low;
- int high;
+ u32 low;
+ u32 high;
};

static inline bool is_llc_occupancy_enabled(void)
diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
index 0c849653a99d..01ffd455313a 100644
--- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
@@ -193,22 +193,21 @@ static void apply_config(struct rdt_hw_domain *hw_dom,
}
}

-static int update_domains(struct rdt_resource *r, int closid)
+static int update_domains(struct rdt_resource *r)
{
struct resctrl_staged_config *cfg;
struct rdt_hw_domain *hw_dom;
+ bool msr_param_init = false;
struct msr_param msr_param;
cpumask_var_t cpu_mask;
struct rdt_domain *d;
bool mba_sc;
+ u32 closid;
int i, cpu;

if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;

- /* TODO: learn these two by looping the config */
- msr_param.low = closid;
- msr_param.high = msr_param.low + 1;
msr_param.res = r;

mba_sc = is_mba_sc(r);
@@ -220,9 +219,21 @@ static int update_domains(struct rdt_resource *r, int closid)
continue;

apply_config(hw_dom, cfg, cpu_mask, mba_sc);
+
+ closid = cfg->closid;
+ if (!msr_param_init) {
+ msr_param.low = closid;
+ msr_param.high = closid;
+ msr_param_init = true;
+ } else {
+ msr_param.low = min(msr_param.low, closid);
+ msr_param.high = max(msr_param.high, closid);
+ }
}
}

+ msr_param.high += 1;
+
/*
* Avoid writing the control msr with control values when
* MBA software controller is enabled
@@ -301,7 +312,7 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
}

for_each_alloc_enabled_rdt_resource(r) {
- ret = update_domains(r, closid);
+ ret = update_domains(r);
if (ret)
goto out;
}
--
2.18.0