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Subject[PATCH v1 20/20] x86/resctrl: Make resctrl_arch_rmid_read() return values in bytes
Date
resctrl_arch_rmid_read() returns a value in chunks, as read from the
hardware. This needs scaling to bytes by mon_scale, as provided by
the architecture code.

Now that resctrl_arch_rmid_read() performs the overflow and corrections
itself, it may as well return a value in bytes directly.

Move the mon_scale conversion into resctrl_arch_rmid_read().

Signed-off-by: James Morse <james.morse@arm.com>
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 6 ++----
arch/x86/kernel/cpu/resctrl/internal.h | 4 ++--
arch/x86/kernel/cpu/resctrl/monitor.c | 22 +++++++++-------------
include/linux/resctrl.h | 2 +-
4 files changed, 14 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 3269ee954941..6b6598811922 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -549,7 +549,6 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
int rdtgroup_mondata_show(struct seq_file *m, void *arg)
{
struct kernfs_open_file *of = m->private;
- struct rdt_hw_resource *hw_res;
u32 resid, evtid, domid;
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
@@ -569,8 +568,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
domid = md.u.domid;
evtid = md.u.evtid;

- hw_res = &rdt_resources_all[resid];
- r = &hw_res->r_resctrl;
+ r = &rdt_resources_all[resid].r_resctrl;
d = rdt_find_domain(r, domid, NULL);
if (IS_ERR_OR_NULL(d)) {
ret = -ENOENT;
@@ -584,7 +582,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
else if (rr.err == -EINVAL)
seq_puts(m, "Unavailable\n");
else
- seq_printf(m, "%llu\n", rr.val * hw_res->mon_scale);
+ seq_printf(m, "%llu\n", rr.val);

out:
rdtgroup_kn_unlock(of->kn);
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 4569b4588185..3bf4b32fc531 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -278,13 +278,13 @@ struct rftype {

/**
* struct mbm_state - status for each MBM counter in each domain
- * @prev_bw_chunks: Previous chunks value read when for bandwidth calculation
+ * @prev_bw_bytes: Previous bytes value read when for bandwidth calculation
* @prev_bw: The most recent bandwidth in MBps
* @delta_bw: Difference between the current and previous bandwidth
* @delta_comp: Indicates whether to compute the delta_bw
*/
struct mbm_state {
- u64 prev_bw_chunks;
+ u64 prev_bw_bytes;
u32 prev_bw;
u32 delta_bw;
bool delta_comp;
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 18eba1bb032f..7de6e7aa2778 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -183,7 +183,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
struct arch_mbm_state *m;
- u64 msr_val;
+ u64 msr_val, chunks;

if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask))
return -EINVAL;
@@ -208,10 +208,11 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
if (m) {
m->chunks += mbm_overflow_count(m->prev_msr, msr_val,
hw_res->mbm_width);
- *val = get_corrected_mbm_count(rmid, m->chunks);
+ chunks = get_corrected_mbm_count(rmid, m->chunks);
+ *val = chunks * hw_res->mon_scale;
m->prev_msr = msr_val;
} else {
- *val = msr_val;
+ *val = msr_val * hw_res->mon_scale;
}

return 0;
@@ -226,7 +227,6 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
void __check_limbo(struct rdt_domain *d, bool force_free)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
- struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct rmid_entry *entry;
u32 crmid = 1, nrmid;
bool rmid_dirty;
@@ -249,7 +249,6 @@ void __check_limbo(struct rdt_domain *d, bool force_free)
QOS_L3_OCCUP_EVENT_ID, &val)) {
rmid_dirty = true;
} else {
- val *= hw_res->mon_scale;
rmid_dirty = (val >= resctrl_rmid_realloc_threshold);
}

@@ -293,7 +292,6 @@ int alloc_rmid(void)
static void add_rmid_to_limbo(struct rmid_entry *entry)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
- struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct rdt_domain *d;
int cpu, err;
u64 val = 0;
@@ -305,7 +303,6 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
err = resctrl_arch_rmid_read(r, d, entry->rmid,
QOS_L3_OCCUP_EVENT_ID,
&val);
- val *= hw_res->mon_scale;
if (err || val <= resctrl_rmid_realloc_threshold)
continue;
}
@@ -370,7 +367,7 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)

if (rr->first) {
memset(m, 0, sizeof(struct mbm_state));
- m->prev_bw_chunks = tval;
+ m->prev_bw_bytes = tval;
return 0;
}

@@ -385,21 +382,20 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
*/
static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
{
- struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);
struct mbm_state *m = &rr->d->mbm_local[rmid];
- u64 cur_bw, bw_chunks = 0;
+ u64 cur_bw, bw_bytes = 0;

- if (resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &bw_chunks))
+ if (resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &bw_bytes))
return;

- cur_bw = (bw_chunks - m->prev_bw_chunks) * hw_res->mon_scale;
+ cur_bw = (bw_bytes - m->prev_bw_bytes);
cur_bw >>= 20;

if (m->delta_comp)
m->delta_bw = abs(cur_bw - m->prev_bw);
m->delta_comp = false;
m->prev_bw = cur_bw;
- m->prev_bw_chunks = bw_chunks;
+ m->prev_bw_bytes = bw_bytes;
}

/*
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index ce7c7472da7d..f63af6d4c10e 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -236,7 +236,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
* @d: The domain that the counter should be read from.
* @rmid: The rmid of the counter to read.
* @eventid: The eventid to read, e.g. L3 occupancy.
- * @val: The result of the counter read in chunks.
+ * @val: The result of the counter read in bytes.
*
* Returns 0 on success, or -EIO, -EINVAL etc on error.
*/
--
2.30.2
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