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Message-ID: <20250811181709.6241-22-tony.luck@intel.com>
Date: Mon, 11 Aug 2025 11:16:55 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghuay@...dia.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
Peter Newman <peternewman@...gle.com>,
James Morse <james.morse@....com>,
Babu Moger <babu.moger@....com>,
Drew Fustini <dfustini@...libre.com>,
Dave Martin <Dave.Martin@....com>,
Anil Keshavamurthy <anil.s.keshavamurthy@...el.com>,
Chen Yu <yu.c.chen@...el.com>
Cc: x86@...nel.org,
linux-kernel@...r.kernel.org,
patches@...ts.linux.dev,
Tony Luck <tony.luck@...el.com>
Subject: [PATCH v8 21/32] x86,fs/resctrl: Add architectural event pointer
The resctrl file system layer passes the domain, RMID, and event id to
resctrl_arch_rmid_read() to fetch an event counter.
For some resources this is not enough information to efficiently access
the counter. Fetching a telemetry event counter requires additional
information that is private to the architecture, for example, the offset
into MMIO space from where counter should be read.
Add mon_evt::arch_priv void pointer. Architecture code can initialize
this when marking each event enabled.
File system code passes this pointer to resctrl_arch_rmid_read().
Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
Signed-off-by: Tony Luck <tony.luck@...el.com>
---
include/linux/resctrl.h | 7 +++++--
fs/resctrl/internal.h | 4 ++++
arch/x86/kernel/cpu/resctrl/core.c | 6 +++---
arch/x86/kernel/cpu/resctrl/monitor.c | 2 +-
fs/resctrl/monitor.c | 14 ++++++++++----
5 files changed, 23 insertions(+), 10 deletions(-)
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 61c73772a177..d729e988a475 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -384,7 +384,7 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);
#define MAX_BINARY_BITS 27
void resctrl_enable_mon_event(enum resctrl_event_id eventid, bool any_cpu,
- unsigned int binary_bits);
+ unsigned int binary_bits, void *arch_priv);
bool resctrl_is_mon_event_enabled(enum resctrl_event_id eventid);
@@ -479,6 +479,9 @@ void resctrl_arch_pre_mount(void);
* only.
* @rmid: rmid of the counter to read.
* @eventid: eventid to read, e.g. L3 occupancy.
+ * @arch_priv: Architecture private data for this event.
+ * The @arch_priv provided by the architecture via
+ * resctrl_enable_mon_event().
* @val: result of the counter read in bytes.
* @arch_mon_ctx: An architecture specific value from
* resctrl_arch_mon_ctx_alloc(), for MPAM this identifies
@@ -496,7 +499,7 @@ void resctrl_arch_pre_mount(void);
*/
int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain_hdr *hdr,
u32 closid, u32 rmid, enum resctrl_event_id eventid,
- u64 *val, void *arch_mon_ctx);
+ void *arch_priv, u64 *val, void *arch_mon_ctx);
/**
* resctrl_arch_rmid_read_context_check() - warn about invalid contexts
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index b16e2fc42b3f..9c1f821279bb 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -62,6 +62,9 @@ static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
* @binary_bits: number of fixed-point binary bits from architecture,
* only valid if @is_floating_point is true
* @enabled: true if the event is enabled
+ * @arch_priv: Architecture private data for this event.
+ * The @arch_priv provided by the architecture via
+ * resctrl_enable_mon_event().
*/
struct mon_evt {
enum resctrl_event_id evtid;
@@ -72,6 +75,7 @@ struct mon_evt {
bool is_floating_point;
unsigned int binary_bits;
bool enabled;
+ void *arch_priv;
};
extern struct mon_evt mon_event_all[QOS_NUM_EVENTS];
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 58756d216fe8..6f455454f38d 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -910,15 +910,15 @@ static __init bool get_rdt_mon_resources(void)
bool ret = false;
if (rdt_cpu_has(X86_FEATURE_CQM_OCCUP_LLC)) {
- resctrl_enable_mon_event(QOS_L3_OCCUP_EVENT_ID, false, 0);
+ resctrl_enable_mon_event(QOS_L3_OCCUP_EVENT_ID, false, 0, NULL);
ret = true;
}
if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL)) {
- resctrl_enable_mon_event(QOS_L3_MBM_TOTAL_EVENT_ID, false, 0);
+ resctrl_enable_mon_event(QOS_L3_MBM_TOTAL_EVENT_ID, false, 0, NULL);
ret = true;
}
if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL)) {
- resctrl_enable_mon_event(QOS_L3_MBM_LOCAL_EVENT_ID, false, 0);
+ resctrl_enable_mon_event(QOS_L3_MBM_LOCAL_EVENT_ID, false, 0, NULL);
ret = true;
}
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 043f777378a6..185b203f6321 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -219,7 +219,7 @@ static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width)
int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain_hdr *hdr,
u32 unused, u32 rmid, enum resctrl_event_id eventid,
- u64 *val, void *ignored)
+ void *arch_priv, u64 *val, void *ignored)
{
int cpu = cpumask_any(&hdr->cpu_mask);
struct rdt_hw_l3_mon_domain *hw_dom;
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 879263db8fa3..40c66caf299d 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -137,9 +137,11 @@ void __check_limbo(struct rdt_l3_mon_domain *d, bool force_free)
struct rmid_entry *entry;
u32 idx, cur_idx = 1;
void *arch_mon_ctx;
+ void *arch_priv;
bool rmid_dirty;
u64 val = 0;
+ arch_priv = mon_event_all[QOS_L3_OCCUP_EVENT_ID].arch_priv;
arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, QOS_L3_OCCUP_EVENT_ID);
if (IS_ERR(arch_mon_ctx)) {
pr_warn_ratelimited("Failed to allocate monitor context: %ld",
@@ -160,7 +162,7 @@ void __check_limbo(struct rdt_l3_mon_domain *d, bool force_free)
entry = __rmid_entry(idx);
if (resctrl_arch_rmid_read(r, &d->hdr, entry->closid, entry->rmid,
- QOS_L3_OCCUP_EVENT_ID, &val,
+ QOS_L3_OCCUP_EVENT_ID, arch_priv, &val,
arch_mon_ctx)) {
rmid_dirty = true;
} else {
@@ -411,7 +413,8 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr)
if (rr->hdr) {
/* Single domain. */
rr->err = resctrl_arch_rmid_read(rr->r, rr->hdr, closid, rmid,
- rr->evt->evtid, &tval, rr->arch_mon_ctx);
+ rr->evt->evtid, rr->evt->arch_priv,
+ &tval, rr->arch_mon_ctx);
if (rr->err)
return rr->err;
@@ -434,7 +437,8 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr)
if (d->ci_id != rr->ci_id)
continue;
err = resctrl_arch_rmid_read(rr->r, &d->hdr, closid, rmid,
- rr->evt->evtid, &tval, rr->arch_mon_ctx);
+ rr->evt->evtid, rr->evt->arch_priv,
+ &tval, rr->arch_mon_ctx);
if (!err) {
rr->val += tval;
ret = 0;
@@ -906,7 +910,8 @@ struct mon_evt mon_event_all[QOS_NUM_EVENTS] = {
MON_EVENT(PMT_EVENT_UOPS_RETIRED, "uops_retired", RDT_RESOURCE_PERF_PKG, false),
};
-void resctrl_enable_mon_event(enum resctrl_event_id eventid, bool any_cpu, unsigned int binary_bits)
+void resctrl_enable_mon_event(enum resctrl_event_id eventid, bool any_cpu,
+ unsigned int binary_bits, void *arch_priv)
{
if (WARN_ON_ONCE(eventid < QOS_FIRST_EVENT || eventid >= QOS_NUM_EVENTS ||
binary_bits > MAX_BINARY_BITS))
@@ -922,6 +927,7 @@ void resctrl_enable_mon_event(enum resctrl_event_id eventid, bool any_cpu, unsig
mon_event_all[eventid].any_cpu = any_cpu;
mon_event_all[eventid].binary_bits = binary_bits;
+ mon_event_all[eventid].arch_priv = arch_priv;
mon_event_all[eventid].enabled = true;
}
--
2.50.1
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