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arm_mpam: Add helper to reset saved mbwu state

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resctrl expects to reset the bandwidth counters when the filesystem
is mounted.

To allow this, add a helper that clears the saved mbwu state. Instead
of cross calling to each CPU that can access the component MSC to
write to the counter, set a flag that causes it to be zero'd on the
the next read. This is easily done by forcing a configuration update.

Signed-off-by: James Morse <james.morse@arm.com>
Cc: Peter Newman <peternewman@google.com>
Reviewed-by: Fenghua Yu <fenghuay@nvdia.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
James Morse
2025-11-19 12:23:01 +00:00
committed by Catalin Marinas
parent 9e5afb7c32
commit 201d96ca4c
2 changed files with 49 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/resctrl/mpam_devices.c
View File

@@ -1075,6 +1075,7 @@ static void __ris_msmon_read(void *arg)
bool overflow;
struct mon_read *m = arg;
struct mon_cfg *ctx = m->ctx;
bool reset_on_next_read = false;
struct mpam_msc_ris *ris = m->ris;
struct msmon_mbwu_state *mbwu_state;
struct mpam_props *rprops = &ris->props;
@@ -1089,6 +1090,20 @@ static void __ris_msmon_read(void *arg)
FIELD_PREP(MSMON_CFG_MON_SEL_RIS, ris->ris_idx);
mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel);
switch (m->type) {
case mpam_feat_msmon_mbwu_31counter:
case mpam_feat_msmon_mbwu_44counter:
case mpam_feat_msmon_mbwu_63counter:
mbwu_state = &ris->mbwu_state[ctx->mon];
if (mbwu_state) {
reset_on_next_read = mbwu_state->reset_on_next_read;
mbwu_state->reset_on_next_read = false;
}
break;
default:
break;
}
/*
* Read the existing configuration to avoid re-writing the same values.
* This saves waiting for 'nrdy' on subsequent reads.
@@ -1106,7 +1121,7 @@ static void __ris_msmon_read(void *arg)
config_mismatch = cur_flt != flt_val ||
cur_ctl != (ctl_val | MSMON_CFG_x_CTL_EN);
if (config_mismatch) {
if (config_mismatch || reset_on_next_read) {
write_msmon_ctl_flt_vals(m, ctl_val, flt_val);
overflow = false;
} else if (overflow) {
@@ -1263,6 +1278,37 @@ int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg *ctx,
return err;
}
void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ctx)
{
struct mpam_msc *msc;
struct mpam_vmsc *vmsc;
struct mpam_msc_ris *ris;
if (!mpam_is_enabled())
return;
guard(srcu)(&mpam_srcu);
list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list,
srcu_read_lock_held(&mpam_srcu)) {
if (!mpam_has_feature(mpam_feat_msmon_mbwu, &vmsc->props))
continue;
msc = vmsc->msc;
list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list,
srcu_read_lock_held(&mpam_srcu)) {
if (!mpam_has_feature(mpam_feat_msmon_mbwu, &ris->props))
continue;
if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc)))
continue;
ris->mbwu_state[ctx->mon].correction = 0;
ris->mbwu_state[ctx->mon].reset_on_next_read = true;
mpam_mon_sel_unlock(msc);
}
}
}
static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd)
{
u32 num_words, msb;

2
drivers/resctrl/mpam_internal.h
View File

@@ -211,6 +211,7 @@ struct mon_cfg {
/* Changes to msmon_mbwu_state are protected by the msc's mon_sel_lock. */
struct msmon_mbwu_state {
bool enabled;
bool reset_on_next_read;
struct mon_cfg cfg;
/*
@@ -370,6 +371,7 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid,
int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg *ctx,
enum mpam_device_features, u64 *val);
void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ctx);
int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level,
cpumask_t *affinity);