The L2 monitor counters always reset to 0 under CDP working mode. This occurs because the L2 monitor employs cumulative statistics, and monitors a single partid within each statistical cycle. After completing the configuration for the new partid monitoring, the monitor instance starts a new monitoring cycle and resets the counter to zero. Since MPAM implements the CDP feature by allocating two partids, switching the monitor's target partid during a monitoring cycle falsely triggers a "new control group" assumption, leading to erroneous counter resets. To resolve this, use the real partid % num_mon to ensure distinct monitor instances track different partids under the CDP control group, preventing unintended resets. Fixes: 585d757fc15c ("fs/resctrl: Create l2 cache monitors") Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- drivers/platform/mpam/mpam_resctrl.c | 42 ++++++++++------------------ 1 file changed, 14 insertions(+), 28 deletions(-) diff --git a/drivers/platform/mpam/mpam_resctrl.c b/drivers/platform/mpam/mpam_resctrl.c index 8de4aae95253..c3f9f0c2a94c 100644 --- a/drivers/platform/mpam/mpam_resctrl.c +++ b/drivers/platform/mpam/mpam_resctrl.c @@ -309,19 +309,8 @@ static void *resctrl_arch_mon_ctx_alloc_no_wait(struct rdt_resource *r, if (!ret) return ERR_PTR(-ENOMEM); - switch (evtid) { - case QOS_L3_OCCUP_EVENT_ID: - case QOS_L3_MBM_LOCAL_EVENT_ID: - case QOS_L3_MBM_TOTAL_EVENT_ID: - case QOS_L2_OCCUP_EVENT_ID: - case QOS_L2_MBM_CORE_EVENT_ID: - *ret = __mon_is_rmid_idx; - return ret; - - default: - kfree(ret); - return ERR_PTR(-EOPNOTSUPP); - } + *ret = __mon_is_rmid_idx; + return ret; } void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid) @@ -371,7 +360,6 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, struct mon_cfg cfg; struct mpam_resctrl_dom *dom; struct mpam_resctrl_res *res; - u32 mon = *(u32 *)arch_mon_ctx; enum mpam_device_features type; resctrl_arch_rmid_read_context_check(); @@ -392,20 +380,15 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, return -EINVAL; } - cfg.mon = mon; - if (cfg.mon == USE_RMID_IDX) { - /* - * The number of mbwu monitors can't support free run mode, - * adapt the remainder of rmid to the num_mon as compromise. - */ - res = container_of(r, struct mpam_resctrl_res, resctrl_res); - if (type == mpam_feat_msmon_mbwu) - num_mon = res->class->props.num_mbwu_mon; - else - num_mon = res->class->props.num_csu_mon; - - cfg.mon = closid % num_mon; - } + /* + * The number of mbwu monitors can't support free run mode, + * adapt the remainder of rmid to the num_mon as compromise. + */ + res = container_of(r, struct mpam_resctrl_res, resctrl_res); + if (type == mpam_feat_msmon_mbwu) + num_mon = res->class->props.num_mbwu_mon; + else + num_mon = res->class->props.num_csu_mon; cfg.match_pmg = true; cfg.pmg = rmid; @@ -413,11 +396,13 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, if (cdp_enabled) { cfg.partid = resctrl_get_config_index(closid, CDP_DATA); + cfg.mon = cfg.partid % num_mon; err = mpam_msmon_read(dom->comp, &cfg, type, val); if (err) return err; cfg.partid = resctrl_get_config_index(closid, CDP_CODE); + cfg.mon = cfg.partid % num_mon; err = mpam_msmon_read(dom->comp, &cfg, type, &cdp_val); if (!err) { pr_debug("read monitor rmid %u %s:%u CODE/DATA: %lld/%lld\n", @@ -427,6 +412,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, } } else { cfg.partid = closid; + cfg.mon = cfg.partid % num_mon; err = mpam_msmon_read(dom->comp, &cfg, type, val); } -- 2.25.1