Commit-ID: f809a8d67ee44cedca6d9acf5b8f6252c108e195
Gitweb: https://git.kernel.org/tip/f809a8d67ee44cedca6d9acf5b8f6252c108e195
Author: Reinette Chatre <reinette.chatre@xxxxxxxxx>
AuthorDate: Fri, 1 Jun 2018 06:09:20 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 20 Jun 2018 00:56:37 +0200
x86/intel_rdt: Add utilities to test pseudo-locked region possibility
A pseudo-locked region does not have a class of service associated with
it and thus not tracked in the array of control values maintained as
part of the domain. Even so, when the user provides a new bitmask for
another resource group it needs to be checked for interference with
existing pseudo-locked regions.
Additionally only one pseudo-locked region can be created in any cache
hierarchy.
Introduce two utilities in support of above scenarios: (1) a utility
that can be used to test if a given capacity bitmask overlaps with any
pseudo-locked regions associated with a particular cache instance, (2) a
utility that can be used to test if a pseudo-locked region exists within
a particular cache hierarchy.
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: fenghua.yu@xxxxxxxxx
Cc: tony.luck@xxxxxxxxx
Cc: vikas.shivappa@xxxxxxxxxxxxxxx
Cc: gavin.hindman@xxxxxxxxx
Cc: jithu.joseph@xxxxxxxxx
Cc: dave.hansen@xxxxxxxxx
Cc: hpa@xxxxxxxxx
Link: https://lkml.kernel.org/r/59b96030bd839dbc474bbac217f9879e45579e52.1527847599.git.reinette.chatre@xxxxxxxxx
---
arch/x86/kernel/cpu/intel_rdt.h | 2 +
arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c | 74 +++++++++++++++++++++++++++++
2 files changed, 76 insertions(+)
diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index 12b006178d3a..119645c83e27 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -503,6 +503,8 @@ enum rdtgrp_mode rdtgroup_mode_by_closid(int closid);
int rdtgroup_tasks_assigned(struct rdtgroup *r);
int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp);
+bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_domain *d, u32 _cbm);
+bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d);
struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r);
int update_domains(struct rdt_resource *r, int closid);
void closid_free(int closid);
diff --git a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
index ce8243c87877..b145a7386b10 100644
--- a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
+++ b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
@@ -299,3 +299,77 @@ int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp)
pseudo_lock_free(rdtgrp);
return 0;
}
+
+/**
+ * rdtgroup_cbm_overlaps_pseudo_locked - Test if CBM or portion is pseudo-locked
+ * @d: RDT domain
+ * @_cbm: CBM to test
+ *
+ * @d represents a cache instance and @_cbm a capacity bitmask that is
+ * considered for it. Determine if @_cbm overlaps with any existing
+ * pseudo-locked region on @d.
+ *
+ * Return: true if @_cbm overlaps with pseudo-locked region on @d, false
+ * otherwise.
+ */
+bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_domain *d, u32 _cbm)
+{
+ unsigned long *cbm = (unsigned long *)&_cbm;
+ unsigned long *cbm_b;
+ unsigned int cbm_len;
+
+ if (d->plr) {
+ cbm_len = d->plr->r->cache.cbm_len;
+ cbm_b = (unsigned long *)&d->plr->cbm;
+ if (bitmap_intersects(cbm, cbm_b, cbm_len))
+ return true;
+ }
+
+ return false;
+}
+
+/**
+ * rdtgroup_pseudo_locked_in_hierarchy - Pseudo-locked region in cache hierarchy
+ * @d: RDT domain under test
+ *
+ * The setup of a pseudo-locked region affects all cache instances within
+ * the hierarchy of the region. It is thus essential to know if any
+ * pseudo-locked regions exist within a cache hierarchy to prevent any
+ * attempts to create new pseudo-locked regions in the same hierarchy.
+ *
+ * Return: true if a pseudo-locked region exists in the hierarchy of @d or
+ * if it is not possible to test due to memory allocation issue,
+ * false otherwise.
+ */
+bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d)
+{
+ cpumask_var_t cpu_with_psl;
+ struct rdt_resource *r;
+ struct rdt_domain *d_i;
+ bool ret = false;
+
+ if (!zalloc_cpumask_var(&cpu_with_psl, GFP_KERNEL))
+ return true;
+
+ /*
+ * First determine which cpus have pseudo-locked regions
+ * associated with them.
+ */
+ for_each_alloc_enabled_rdt_resource(r) {
+ list_for_each_entry(d_i, &r->domains, list) {
+ if (d_i->plr)
+ cpumask_or(cpu_with_psl, cpu_with_psl,
+ &d_i->cpu_mask);
+ }
+ }
+
+ /*
+ * Next test if new pseudo-locked region would intersect with
+ * existing region.
+ */
+ if (cpumask_intersects(&d->cpu_mask, cpu_with_psl))
+ ret = true;
+
+ free_cpumask_var(cpu_with_psl);
+ return ret;
+}
--
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