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

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

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 42a1abb378f018b775c4d13ee934a6f20836527a..1dafbdc5ac31627e9391832fdf032685871eb637 100644 (file)
--- 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 c05e9b7cf77a66780e42ba610c356741c120ed24..5f7128686cfd2f851b92707afedd6e7d313dfeab 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -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;

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 8d15568d7121c4d03fc93fc3027040ce5c89a475..efe0c30d3a12d5f126a129d81bcac921dda97252 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -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);

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index cb857f75332286fa69eca2f0747deed352e71d49..0cf5b20c6ddf8e5187d674b06f224d579d6f7d66 100644 (file)
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -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.
  *