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x86/resctrl: Make resctrl_arch_rmid_read() return values in bytes

Browse source 
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. This allows
the accesses to the architecture specific 'hw' structure to be removed.

Move the mon_scale conversion into resctrl_arch_rmid_read().
mbm_bw_count() is updated to calculate bandwidth from bytes.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <quic_jiles@quicinc.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20220902154829.30399-22-james.morse@arm.com
This commit is contained in:
James Morse 2022-09-02 15:48:29 +00:00 committed by Borislav Petkov
parent d80975e264
commit f7b1843eca
4 changed files with 16 additions and 20 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
arch/x86/kernel/cpu/resctrl/ctrlmondata.c
View file

@ -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);

4
arch/x86/kernel/cpu/resctrl/internal.h
View file

@ -279,13 +279,13 @@ struct rftype {
/**
* struct mbm_state - status for each MBM counter in each domain
* @prev_bw_chunks: Previous chunks value read for bandwidth calculation
* @prev_bw_bytes: Previous bytes value read 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;

24
arch/x86/kernel/cpu/resctrl/monitor.c
View file

@ -16,6 +16,7 @@
*/
#include <linux/module.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <asm/cpu_device_id.h>
@ -189,7 +190,7 @@ 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 *am;
u64 msr_val;
u64 msr_val, chunks;
if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask))
return -EINVAL;
@ -214,12 +215,14 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
if (am) {
am->chunks += mbm_overflow_count(am->prev_msr, msr_val,
hw_res->mbm_width);
*val = get_corrected_mbm_count(rmid, am->chunks);
chunks = get_corrected_mbm_count(rmid, am->chunks);
am->prev_msr = msr_val;
} else {
*val = msr_val;
chunks = msr_val;
}
*val = chunks * hw_res->mon_scale;
return 0;
}
@ -232,7 +235,6 @@ 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;
@ -255,7 +257,6 @@ 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);
}
@ -299,7 +300,6 @@ 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;
@ -311,7 +311,6 @@ 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;
}
@ -403,15 +402,14 @@ 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, chunks, cur_chunks;
u64 cur_bw, bytes, cur_bytes;
cur_chunks = rr->val;
chunks = cur_chunks - m->prev_bw_chunks;
m->prev_bw_chunks = cur_chunks;
cur_bytes = rr->val;
bytes = cur_bytes - m->prev_bw_bytes;
m->prev_bw_bytes = cur_bytes;
cur_bw = (chunks * hw_res->mon_scale) >> 20;
cur_bw = bytes / SZ_1M;
if (m->delta_comp)
m->delta_bw = abs(cur_bw - m->prev_bw);

2
include/linux/resctrl.h
View file

@ -227,7 +227,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
* @d: domain that the counter should be read from.
* @rmid: rmid of the counter to read.
* @eventid: eventid to read, e.g. L3 occupancy.
* @val: result of the counter read in chunks.
* @val: result of the counter read in bytes.
*
* Call from process context on a CPU that belongs to domain @d.
*