[RFC PATCH 13/17] x86/resctrl: Build lookup table for package events

From: Tony Luck
Date: Mon Mar 03 2025 - 18:36:49 EST


The resctrl filesystem saves the evt_type in the private data pointer
of the kernfs_node of each file in the mon_data directories.

To print the values for each file the show() function will need to map
from this evtid to:

num_rmids - to make sure data for this file exists
guid - to pick the pmt_event(s) for each package
stride/offset - to compute MMIO offset for this RMID/event

Build a lookup table for each event to save searching through
lists and add macros for ease of use.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
arch/x86/kernel/cpu/resctrl/intel_pmt.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/intel_pmt.c b/arch/x86/kernel/cpu/resctrl/intel_pmt.c
index 05640e85d303..c5557d7f5fbe 100644
--- a/arch/x86/kernel/cpu/resctrl/intel_pmt.c
+++ b/arch/x86/kernel/cpu/resctrl/intel_pmt.c
@@ -38,6 +38,18 @@ enum pmt_event_id {
PMT_NUM_EVENTS
};

+static struct evtinfo {
+ struct telem_entry *telem_entry;
+ struct pmt_event *pmt_event;
+} evtinfo[PMT_NUM_EVENTS];
+
+#define EVT_NUM_RMIDS(evtid) (evtinfo[evtid].telem_entry->num_rmids)
+#define EVT_STRIDE(evtid) (evtinfo[evtid].telem_entry->stride)
+#define EVT_GUID(evtid) (evtinfo[evtid].telem_entry->guid)
+
+#define EVT_OFFSET(evtid) (evtinfo[evtid].pmt_event->evt_offset)
+#define EVT_TYPE(evtid) (evtinfo[evtid].pmt_event->evt_type)
+
enum evt_type {
EVT_U64,
EVT_U46_18,
@@ -274,6 +286,9 @@ void rdt_get_intel_pmt_mount(void)
for (int i = 0; (*tentry)->evts[i].evt.name; i++) {
evt = &(*tentry)->evts[i].evt;
list_add_tail(&evt->list, &r->evt_list);
+
+ evtinfo[evt->evtid].telem_entry = *tentry;
+ evtinfo[evt->evtid].pmt_event = &(*tentry)->evts[i];
ret = true;
}
if (!r->num_rmid)
--
2.48.1