Reduce redundant counter reads with resctrl refactoring

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Merge tag 'x86_cache_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 resctrl update from Dave Hansen:
 "Reduce redundant counter reads with resctrl refactoring"

* tag 'x86_cache_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Avoid redundant counter read in __mon_event_count()
This commit is contained in:
Linus Torvalds 2023-04-28 09:30:51 -07:00
commit 4980c176a7

View file

@ -383,41 +383,36 @@ void free_rmid(u32 rmid)
list_add_tail(&entry->list, &rmid_free_lru);
}
static struct mbm_state *get_mbm_state(struct rdt_domain *d, u32 rmid,
enum resctrl_event_id evtid)
{
switch (evtid) {
case QOS_L3_MBM_TOTAL_EVENT_ID:
return &d->mbm_total[rmid];
case QOS_L3_MBM_LOCAL_EVENT_ID:
return &d->mbm_local[rmid];
default:
return NULL;
}
}
static int __mon_event_count(u32 rmid, struct rmid_read *rr)
{
struct mbm_state *m;
u64 tval = 0;
if (rr->first)
if (rr->first) {
resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid);
m = get_mbm_state(rr->d, rmid, rr->evtid);
if (m)
memset(m, 0, sizeof(struct mbm_state));
return 0;
}
rr->err = resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval);
if (rr->err)
return rr->err;
switch (rr->evtid) {
case QOS_L3_OCCUP_EVENT_ID:
rr->val += tval;
return 0;
case QOS_L3_MBM_TOTAL_EVENT_ID:
m = &rr->d->mbm_total[rmid];
break;
case QOS_L3_MBM_LOCAL_EVENT_ID:
m = &rr->d->mbm_local[rmid];
break;
default:
/*
* Code would never reach here because an invalid
* event id would fail in resctrl_arch_rmid_read().
*/
return -EINVAL;
}
if (rr->first) {
memset(m, 0, sizeof(struct mbm_state));
return 0;
}
rr->val += tval;
return 0;