[PATCH v1 02/31] x86/resctrl: Add a helper to avoid reaching into the arch code resource list

James Morse
2024-03-21T16:51:36Z

Resctrl occasionally wants to know something about a specific resource,
in these cases it reaches into the arch code's rdt_resources_all[]
array.

Once the filesystem parts of resctrl are moved to /fs/, this means it
will need visibility of the architecture specific struct
resctrl_hw_resource definition, and the array of all resources.
All architectures would also need a r_resctrl member in this struct.

Instead, abstract this via a helper to allow architectures to do
different things here. Move the level enum to the resctrl header and
add a helper to retrieve the struct rdt_resource by 'rid'.

resctrl_arch_get_resource() should not return NULL for any value in
the enum, it may instead return a dummy resource that is
!alloc_enabled && !mon_enabled.

Signed-off-by: James Morse <james.morse@arm.com>
---
arch/x86/kernel/cpu/resctrl/core.c | 10 +++++++++-
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 2 +-
arch/x86/kernel/cpu/resctrl/internal.h | 10 ----------
arch/x86/kernel/cpu/resctrl/monitor.c | 8 ++++----
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 15 +++++++--------
include/linux/resctrl.h | 17 +++++++++++++++++
6 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 83e40341583e..b773b3bdebe3 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -122,6 +122,14 @@ struct rdt_hw_resource rdt_resources_all[] = {
},
};

+struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l)
+{
+ if (l >= RDT_NUM_RESOURCES)
+ return NULL;
+
+ return &rdt_resources_all[l].r_resctrl;
+}
+
/*
* cache_alloc_hsw_probe() - Have to probe for Intel haswell server CPUs
* as they do not have CPUID enumeration support for Cache allocation.
@@ -169,7 +177,7 @@ static inline void cache_alloc_hsw_probe(void)
bool is_mba_sc(struct rdt_resource *r)
{
if (!r)
- return rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl.membw.mba_sc;
+ r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);

/*
* The software controller support is only applicable to MBA resource.
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 7997b47743a2..788ac0395645 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -599,7 +599,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
domid = md.u.domid;
evtid = md.u.evtid;

- r = &rdt_resources_all[resid].r_resctrl;
+ r = resctrl_arch_get_resource(resid);
d = rdt_find_domain(r, domid, NULL);
if (IS_ERR_OR_NULL(d)) {
ret = -ENOENT;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index c99f26ebe7a6..65990def6c79 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -466,16 +466,6 @@ extern struct rdt_hw_resource rdt_resources_all[];
extern struct rdtgroup rdtgroup_default;
extern struct dentry *debugfs_resctrl;

-enum resctrl_res_level {
- RDT_RESOURCE_L3,
- RDT_RESOURCE_L2,
- RDT_RESOURCE_MBA,
- RDT_RESOURCE_SMBA,
-
- /* Must be the last */
- RDT_NUM_RESOURCES,
-};
-
static inline struct rdt_resource *resctrl_inc(struct rdt_resource *res)
{
struct rdt_hw_resource *hw_res = resctrl_to_arch_res(res);
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index c34a35ec0f03..06565153ceb2 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -321,7 +321,7 @@ static void limbo_release_entry(struct rmid_entry *entry)
*/
void __check_limbo(struct rdt_domain *d, bool force_free)
{
- struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
u32 idx_limit = resctrl_arch_system_num_rmid_idx();
struct rmid_entry *entry;
u32 idx, cur_idx = 1;
@@ -467,7 +467,7 @@ int alloc_rmid(u32 closid)

static void add_rmid_to_limbo(struct rmid_entry *entry)
{
- struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
struct rdt_domain *d;
u32 idx;

@@ -669,7 +669,7 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
if (!is_mbm_local_enabled())
return;

- r_mba = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;
+ r_mba = resctrl_arch_get_resource(RDT_RESOURCE_MBA);

closid = rgrp->closid;
rmid = rgrp->mon.rmid;
@@ -839,7 +839,7 @@ void mbm_handle_overflow(struct work_struct *work)
if (!resctrl_mounted || !resctrl_arch_mon_capable())
goto out_unlock;

- r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+ r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
d = container_of(work, struct rdt_domain, mbm_over.work);

list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 1767c1affa60..45372b6a6215 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2253,7 +2253,7 @@ static void l2_qos_cfg_update(void *arg)

static inline bool is_mba_linear(void)
{
- return rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl.membw.delay_linear;
+ return resctrl_arch_get_resource(RDT_RESOURCE_MBA)->membw.delay_linear;
}

static int set_cache_qos_cfg(int level, bool enable)
@@ -2341,7 +2341,7 @@ static void mba_sc_domain_destroy(struct rdt_resource *r,
*/
static bool supports_mba_mbps(void)
{
- struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);

return (is_mbm_local_enabled() &&
r->alloc_capable && is_mba_linear());
@@ -2353,7 +2353,7 @@ static bool supports_mba_mbps(void)
*/
static int set_mba_sc(bool mba_sc)
{
- struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
u32 num_closid = resctrl_arch_get_num_closid(r);
struct rdt_domain *d;
int i;
@@ -2625,10 +2625,10 @@ static void schemata_list_destroy(void)

static int rdt_get_tree(struct fs_context *fc)
{
+ struct rdt_resource *l3 = resctrl_arch_get_resource(RDT_RESOURCE_L3);
struct rdt_fs_context *ctx = rdt_fc2context(fc);
unsigned long flags = RFTYPE_CTRL_BASE;
struct rdt_domain *dom;
- struct rdt_resource *r;
int ret;

cpus_read_lock();
@@ -2701,8 +2701,7 @@ static int rdt_get_tree(struct fs_context *fc)
resctrl_mounted = true;

if (is_mbm_enabled()) {
- r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
- list_for_each_entry(dom, &r->domains, list)
+ list_for_each_entry(dom, &l3->domains, list)
mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL,
RESCTRL_PICK_ANY_CPU);
}
@@ -3878,7 +3877,7 @@ static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
seq_puts(seq, ",cdpl2");

- if (is_mba_sc(&rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl))
+ if (is_mba_sc(resctrl_arch_get_resource(RDT_RESOURCE_MBA)))
seq_puts(seq, ",mba_MBps");

if (resctrl_debug)
@@ -4068,7 +4067,7 @@ static void clear_childcpus(struct rdtgroup *r, unsigned int cpu)

void resctrl_offline_cpu(unsigned int cpu)
{
- struct rdt_resource *l3 = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+ struct rdt_resource *l3 = resctrl_arch_get_resource(RDT_RESOURCE_L3);
struct rdtgroup *rdtgrp;
struct rdt_domain *d;

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index a365f67131ec..168cc9510069 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -36,6 +36,16 @@ enum resctrl_conf_type {
CDP_DATA,
};

+enum resctrl_res_level {
+ RDT_RESOURCE_L3,
+ RDT_RESOURCE_L2,
+ RDT_RESOURCE_MBA,
+ RDT_RESOURCE_SMBA,
+
+ /* Must be the last */
+ RDT_NUM_RESOURCES,
+};
+
#define CDP_NUM_TYPES (CDP_DATA + 1)

/*
@@ -190,6 +200,13 @@ struct rdt_resource {
bool cdp_capable;
};

+/*
+ * Get the resource that exists at this level. If the level is not supported
+ * a dummy/not-capable resource can be returned. Levels >= RDT_NUM_RESOURCES
+ * will return NULL.
+ */
+struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l);
+
/**
* struct resctrl_schema - configuration abilities of a resource presented to
* user-space
--
2.39.2