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Message-Id: <20210729223610.29373-7-james.morse@arm.com>
Date: Thu, 29 Jul 2021 22:35:56 +0000
From: James Morse <james.morse@....com>
To: x86@...nel.org, linux-kernel@...r.kernel.org
Cc: Fenghua Yu <fenghua.yu@...el.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
H Peter Anvin <hpa@...or.com>,
Babu Moger <Babu.Moger@....com>,
James Morse <james.morse@....com>,
shameerali.kolothum.thodi@...wei.com,
Jamie Iles <jamie@...iainc.com>,
D Scott Phillips OS <scott@...amperecomputing.com>,
lcherian@...vell.com, bobo.shaobowang@...wei.com
Subject: [PATCH v1 06/20] x86/resctrl: Switch over to the resctrl mbps_val list
Updates to resctrl's software controller follow the same path as
other configuration updates, but they don't modify the hardware state.
rdtgroup_schemata_write() uses parse_line() and the resource's
ctrlval_parse function to stage the configuration.
resctrl_arch_update_domains() then updates the mbps_val[] array
instead, and resctrl_arch_update_domains() skips the rdt_ctrl_update()
call that would update hardware.
This complicates the interface between resctrl's filesystem parts
and architecture specific code. It should be possible for mba_sc
to be completely implemented by the filesystem parts of resctrl. This
would allow it to work on a second architecture with no additional code.
Change parse_bw() to write the configuration value directly to the
mba_sc[] array in the domain structure. Change rdtgroup_schemata_write()
to skip the call to resctrl_arch_update_domains(), meaning all the
mba_sc specific code in resctrl_arch_update_domains() can be removed.
On the read-side, show_doms() and update_mba_bw() are changed to read
the mba_sc[] array from the domain structure. With this,
resctrl_arch_get_config() no longer needs to consider mba_sc resources.
Change parse_bw() to write these values directly, meaning
rdtgroup_schemata_write() never needs to call update_domains()
for mba_sc resources.
Get show_doms() to test is_mba_sc() and retrieve the value
directly, instead of using get_config() for the hardware value.
This means the arch code's resctrl_arch_get_config() and
resctrl_arch_update_domains() no longer need to be aware of
mba_sc, and we can get rid of the update_mba_bw() code that
reaches into the hw_dom to get the msr value.
Signed-off-by: James Morse <james.morse@....com>
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 45 ++++++++++++++---------
arch/x86/kernel/cpu/resctrl/monitor.c | 10 ++---
2 files changed, 31 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 9e1c6730520b..56789ea11185 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -61,6 +61,7 @@ int parse_bw(struct rdt_parse_data *data, struct resctrl_schema *s,
struct rdt_domain *d)
{
struct resctrl_staged_config *cfg;
+ u32 closid = data->rdtgrp->closid;
struct rdt_resource *r = s->res;
unsigned long bw_val;
@@ -72,6 +73,12 @@ int parse_bw(struct rdt_parse_data *data, struct resctrl_schema *s,
if (!bw_validate(data->buf, &bw_val, r))
return -EINVAL;
+
+ if (is_mba_sc(r)) {
+ d->mba_sc[closid].mbps_val = bw_val;
+ return 0;
+ }
+
cfg->new_ctrl = bw_val;
cfg->have_new_ctrl = true;
@@ -261,14 +268,13 @@ static u32 get_config_index(u32 closid, enum resctrl_conf_type type)
static bool apply_config(struct rdt_hw_domain *hw_dom,
struct resctrl_staged_config *cfg, u32 idx,
- cpumask_var_t cpu_mask, bool mba_sc)
+ cpumask_var_t cpu_mask)
{
struct rdt_domain *dom = &hw_dom->d_resctrl;
- u32 *dc = !mba_sc ? hw_dom->ctrl_val : hw_dom->mbps_val;
- if (cfg->new_ctrl != dc[idx]) {
+ if (cfg->new_ctrl != hw_dom->ctrl_val[idx]) {
cpumask_set_cpu(cpumask_any(&dom->cpu_mask), cpu_mask);
- dc[idx] = cfg->new_ctrl;
+ hw_dom->ctrl_val[idx] = cfg->new_ctrl;
return true;
}
@@ -284,14 +290,12 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
enum resctrl_conf_type t;
cpumask_var_t cpu_mask;
struct rdt_domain *d;
- bool mba_sc;
int cpu;
u32 idx;
if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
return -ENOMEM;
- mba_sc = is_mba_sc(r);
msr_param.res = NULL;
list_for_each_entry(d, &r->domains, list) {
hw_dom = resctrl_to_arch_dom(d);
@@ -301,7 +305,7 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
continue;
idx = get_config_index(closid, t);
- if (!apply_config(hw_dom, cfg, idx, cpu_mask, mba_sc))
+ if (!apply_config(hw_dom, cfg, idx, cpu_mask))
continue;
if (!msr_param.res) {
@@ -315,11 +319,7 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
}
}
- /*
- * Avoid writing the control msr with control values when
- * MBA software controller is enabled
- */
- if (cpumask_empty(cpu_mask) || mba_sc)
+ if (cpumask_empty(cpu_mask))
goto done;
cpu = get_cpu();
/* Update resource control msr on this CPU if it's in cpu_mask. */
@@ -406,6 +406,14 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
list_for_each_entry(s, &resctrl_schema_all, list) {
r = s->res;
+
+ /*
+ * Writes to mba_sc resources update the software controller,
+ * not the control msr.
+ */
+ if (is_mba_sc(r))
+ continue;
+
ret = resctrl_arch_update_domains(r, rdtgrp->closid);
if (ret)
goto out;
@@ -433,10 +441,7 @@ void resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
u32 idx = get_config_index(closid, type);
- if (!is_mba_sc(r))
- *value = hw_dom->ctrl_val[idx];
- else
- *value = hw_dom->mbps_val[idx];
+ *value = hw_dom->ctrl_val[idx];
}
static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int closid)
@@ -451,8 +456,12 @@ static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int clo
if (sep)
seq_puts(s, ";");
- resctrl_arch_get_config(r, dom, closid, schema->conf_type,
- &ctrl_val);
+ if (is_mba_sc(r))
+ ctrl_val = dom->mba_sc[closid].mbps_val;
+ else
+ resctrl_arch_get_config(r, dom, closid,
+ schema->conf_type, &ctrl_val);
+
seq_printf(s, r->format_str, dom->id, max_data_width,
ctrl_val);
sep = true;
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 035e45e711ae..dcf3a73e2c17 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -442,13 +442,11 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
hw_dom_mba = resctrl_to_arch_dom(dom_mba);
cur_bw = pmbm_data->prev_bw;
- resctrl_arch_get_config(r_mba, dom_mba, closid, CDP_NONE, &user_bw);
+ user_bw = dom_mba->mba_sc[closid].mbps_val;
delta_bw = pmbm_data->delta_bw;
- /*
- * resctrl_arch_get_config() chooses the mbps/ctrl value to return
- * based on is_mba_sc(). For now, reach into the hw_dom.
- */
- cur_msr_val = hw_dom_mba->ctrl_val[closid];
+
+ /* MBA monitor resource doesn't support CDP */
+ resctrl_arch_get_config(r_mba, dom_mba, closid, CDP_NONE, &cur_msr_val);
/*
* For Ctrl groups read data from child monitor groups.
--
2.30.2
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