leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

x86/intel_rdt: Add utilities to test pseudo-locked region possibility

Browse Source 
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@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/b8e31dbdcf22ddf71df46072647b47e7558abb32.1529706536.git.reinette.chatre@intel.com
This commit is contained in:
Reinette Chatre 2018-06-22 15:42:19 -07:00 committed by Thomas Gleixner
parent 17eafd0762
commit 72d5050566
2 changed files with 76 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kernel/cpu/intel_rdt.h
View File

@ -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);

74
arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c
View File

@ -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;
}