[PATCH V2 07/10] x86/resctrl: Remove unnecessary pointer to pseudo-locked region

Reinette Chatre
2019-07-30T17:32:20Z

Each cache domain (struct rdt_domain) contains a pointer to a
pseudo-locked region that (if set) is associated with it. At the
same time each resource group (struct rdtgroup) also contains a
pointer to a pseudo-locked region that (if set) is associated with
it.

If a pointer from a cache domain to its pseudo-locked region is
maintained then multiple cache domains could point to a single
pseudo-locked region when a pseudo-locked region spans multiple
resources. Such an arrangement would make it harder to support the
current mechanism of iterating over cache domains in order to find all
pseudo-locked regions.

In preparation for pseudo-locked regions that could span multiple
resources the pointer from a cache domain to a pseudo-locked region is
removed. The pointer to a pseudo-locked region from a resource
group remains - when needing to process all pseudo-locked regions on the
system an iteration over all resource groups is used instead of an
iteration over all cache domains.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 3 +-
arch/x86/kernel/cpu/resctrl/internal.h | 6 +--
arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 46 +++++++++++------------
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 8 ++--
4 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 072f584cb238..a0383ff80afe 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -217,7 +217,7 @@ int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,

if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
rdtgrp->mode == RDT_MODE_SHAREABLE) &&
- rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
+ rdtgroup_cbm_overlaps_pseudo_locked(r, d, cbm_val)) {
rdt_last_cmd_puts("CBM overlaps with pseudo-locked region\n");
return -EINVAL;
}
@@ -293,7 +293,6 @@ static int parse_line(char *line, struct rdt_resource *r,
rdtgrp->plr->r = r;
rdtgrp->plr->d_id = d->id;
rdtgrp->plr->cbm = d->new_ctrl;
- d->plr = rdtgrp->plr;
return 0;
}
goto next;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index f17633cf4776..892f38899dda 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -309,7 +309,6 @@ struct mbm_state {
* @mbps_val: When mba_sc is enabled, this holds the bandwidth in MBps
* @new_ctrl: new ctrl value to be loaded
* @have_new_ctrl: did user provide new_ctrl for this domain
- * @plr: pseudo-locked region (if any) associated with domain
*/
struct rdt_domain {
struct list_head list;
@@ -326,7 +325,6 @@ struct rdt_domain {
u32 *mbps_val;
u32 new_ctrl;
bool have_new_ctrl;
- struct pseudo_lock_region *plr;
};

/**
@@ -567,7 +565,9 @@ 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, unsigned long cbm);
+bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_resource *r,
+ struct rdt_domain *d,
+ unsigned long cbm);
u32 rdtgroup_pseudo_locked_bits(struct rdt_resource *r, struct rdt_domain *d);
bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d);
int rdt_pseudo_lock_init(void);
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index f16702a076a3..733cb7f34948 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -272,17 +272,10 @@ static int pseudo_lock_cstates_constrain(struct pseudo_lock_region *plr,
*/
static void pseudo_lock_region_clear(struct pseudo_lock_region *plr)
{
- struct rdt_domain *d;
-
plr->size = 0;
plr->line_size = 0;
kfree(plr->kmem);
plr->kmem = NULL;
- if (plr->r && plr->d_id >= 0) {
- d = rdt_find_domain(plr->r, plr->d_id, NULL);
- if (!IS_ERR_OR_NULL(d))
- d->plr = NULL;
- }
plr->r = NULL;
plr->d_id = -1;
plr->cbm = 0;
@@ -822,6 +815,7 @@ int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp)

/**
* rdtgroup_cbm_overlaps_pseudo_locked - Test if CBM or portion is pseudo-locked
+ * @r: RDT resource to which @d belongs
* @d: RDT domain
* @cbm: CBM to test
*
@@ -835,17 +829,17 @@ int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp)
* Return: true if @cbm overlaps with pseudo-locked region on @d, false
* otherwise.
*/
-bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_domain *d, unsigned long cbm)
+bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_resource *r,
+ struct rdt_domain *d,
+ unsigned long cbm)
{
+ unsigned long pseudo_locked;
unsigned int cbm_len;
- unsigned long cbm_b;

- if (d->plr) {
- cbm_len = d->plr->r->cache.cbm_len;
- cbm_b = d->plr->cbm;
- if (bitmap_intersects(&cbm, &cbm_b, cbm_len))
- return true;
- }
+ pseudo_locked = rdtgroup_pseudo_locked_bits(r, d);
+ cbm_len = r->cache.cbm_len;
+ if (bitmap_intersects(&cbm, &pseudo_locked, cbm_len))
+ return true;
return false;
}

@@ -859,13 +853,13 @@ bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_domain *d, unsigned long cbm
* 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.
+ * if it is not possible to test due to memory allocation or other
+ * failure, false otherwise.
*/
bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d)
{
cpumask_var_t cpu_with_psl;
- struct rdt_resource *r;
+ struct rdtgroup *rdtgrp;
struct rdt_domain *d_i;
bool ret = false;

@@ -876,11 +870,16 @@ bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d)
* 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);
+ list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
+ if (rdtgrp->plr && rdtgrp->plr->d_id >= 0) {
+ d_i = rdt_find_domain(rdtgrp->plr->r, rdtgrp->plr->d_id,
+ NULL);
+ if (IS_ERR_OR_NULL(d_i)) {
+ ret = true;
+ goto out;
+ }
+ cpumask_or(cpu_with_psl, cpu_with_psl,
+ &d_i->cpu_mask);
}
}

@@ -891,6 +890,7 @@ bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d)
if (cpumask_intersects(&d->cpu_mask, cpu_with_psl))
ret = true;

+out:
free_cpumask_var(cpu_with_psl);
return ret;
}
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index c4bf6ed8b031..0c1786f09963 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -845,8 +845,10 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of,
break;
}
}
+
+ pseudo_locked = rdtgroup_pseudo_locked_bits(r, dom);
+
for (i = r->cache.cbm_len - 1; i >= 0; i--) {
- pseudo_locked = dom->plr ? dom->plr->cbm : 0;
hwb = test_bit(i, &hw_shareable);
swb = test_bit(i, &sw_shareable);
excl = test_bit(i, &exclusive);
@@ -2541,8 +2543,8 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
d->new_ctrl |= *ctrl | peer_ctl;
}
}
- if (d->plr && d->plr->cbm > 0)
- used_b |= d->plr->cbm;
+
+ used_b |= rdtgroup_pseudo_locked_bits(r, d);
unused_b = used_b ^ (BIT_MASK(r->cache.cbm_len) - 1);
unused_b &= BIT_MASK(r->cache.cbm_len) - 1;
d->new_ctrl |= unused_b;
--
2.17.2