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x86/intel_rdt: Pseudo-lock region creation/removal core
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The user requests a pseudo-locked region by providing a schemata to a
resource group that is in the pseudo-locksetup mode. This is the
functionality that consumes the parsed user data and creates the
pseudo-locked region.

First, required information is deduced from user provided data.
This includes, how much memory does the requested bitmask represent,
which CPU the requested region is associated with, and what is the
cache line size of that cache (to learn the stride needed for locking).
Second, a contiguous block of memory matching the requested bitmask is
allocated.

Finally, pseudo-locking is performed. The resource group already has the
allocation that reflects the requested bitmask. With this class of service
active and interference minimized, the allocated memory is loaded into the
cache.

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/67391160bbf06143bc62d856d3d234eb152008b7.1529706536.git.reinette.chatre@intel.com
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Reinette Chatre authored and Thomas Gleixner committed Jun 23, 2018
1 parent f2a1772 commit 018961a
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17 changes: 17 additions & 0 deletions arch/x86/kernel/cpu/intel_rdt.h
Original file line number Diff line number Diff line change
Expand Up @@ -129,11 +129,26 @@ struct mongroup {
* @d: RDT domain to which this pseudo-locked region
* belongs
* @cbm: bitmask of the pseudo-locked region
* @lock_thread_wq: waitqueue used to wait on the pseudo-locking thread
* completion
* @thread_done: variable used by waitqueue to test if pseudo-locking
* thread completed
* @cpu: core associated with the cache on which the setup code
* will be run
* @line_size: size of the cache lines
* @size: size of pseudo-locked region in bytes
* @kmem: the kernel memory associated with pseudo-locked region
*/
struct pseudo_lock_region {
struct rdt_resource *r;
struct rdt_domain *d;
u32 cbm;
wait_queue_head_t lock_thread_wq;
int thread_done;
int cpu;
unsigned int line_size;
unsigned int size;
void *kmem;
};

/**
Expand Down Expand Up @@ -505,6 +520,8 @@ 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);
int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp);
void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp);
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);
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