From: Babu Moger Date: Fri, 5 Sep 2025 21:34:22 +0000 (-0500) Subject: fs/resctrl: Support counter read/reset with mbm_event assignment mode X-Git-Tag: v6.18-rc1~186^2~11 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=159f36cd4de7718779fd0b232de5137b4ffd2d1e;p=thirdparty%2Flinux.git fs/resctrl: Support counter read/reset with mbm_event assignment mode When "mbm_event" counter assignment mode is enabled, the architecture requires a counter ID to read the event data. Introduce an is_mbm_cntr field in struct rmid_read to indicate whether counter assignment mode is in use. Update the logic to call resctrl_arch_cntr_read() and resctrl_arch_reset_cntr() when the assignment mode is active. Report 'Unassigned' in case the user attempts to read an event without assigning a hardware counter. Suggested-by: Reinette Chatre Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com --- diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst index 446736dbd97f1..4c24c5f3f4c19 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -434,6 +434,12 @@ When monitoring is enabled all MON groups will also contain: for the L3 cache they occupy). These are named "mon_sub_L3_YY" where "YY" is the node number. + When the 'mbm_event' counter assignment mode is enabled, reading + an MBM event of a MON group returns 'Unassigned' if no hardware + counter is assigned to it. For CTRL_MON groups, 'Unassigned' is + returned if the MBM event does not have an assigned counter in the + CTRL_MON group nor in any of its associated MON groups. + "mon_hw_id": Available only with debug option. The identifier used by hardware for the monitor group. On x86 this is the RMID. diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c index 42b281b3852ff..0d0ef54fc4de1 100644 --- a/fs/resctrl/ctrlmondata.c +++ b/fs/resctrl/ctrlmondata.c @@ -563,10 +563,15 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, rr->r = r; rr->d = d; rr->first = first; - rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evtid); - if (IS_ERR(rr->arch_mon_ctx)) { - rr->err = -EINVAL; - return; + if (resctrl_arch_mbm_cntr_assign_enabled(r) && + resctrl_is_mbm_event(evtid)) { + rr->is_mbm_cntr = true; + } else { + rr->arch_mon_ctx = resctrl_arch_mon_ctx_alloc(r, evtid); + if (IS_ERR(rr->arch_mon_ctx)) { + rr->err = -EINVAL; + return; + } } cpu = cpumask_any_housekeeping(cpumask, RESCTRL_PICK_ANY_CPU); @@ -582,7 +587,8 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, else smp_call_on_cpu(cpu, smp_mon_event_count, rr, false); - resctrl_arch_mon_ctx_free(r, evtid, rr->arch_mon_ctx); + if (rr->arch_mon_ctx) + resctrl_arch_mon_ctx_free(r, evtid, rr->arch_mon_ctx); } int rdtgroup_mondata_show(struct seq_file *m, void *arg) @@ -653,10 +659,16 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) checkresult: + /* + * -ENOENT is a special case, set only when "mbm_event" counter assignment + * mode is enabled and no counter has been assigned. + */ if (rr.err == -EIO) seq_puts(m, "Error\n"); else if (rr.err == -EINVAL) seq_puts(m, "Unavailable\n"); + else if (rr.err == -ENOENT) + seq_puts(m, "Unassigned\n"); else seq_printf(m, "%llu\n", rr.val); diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h index c6b66d4a6a375..2f1f2efe2f40f 100644 --- a/fs/resctrl/internal.h +++ b/fs/resctrl/internal.h @@ -111,6 +111,8 @@ struct mon_data { * @evtid: Which monitor event to read. * @first: Initialize MBM counter when true. * @ci: Cacheinfo for L3. Only set when @d is NULL. Used when summing domains. + * @is_mbm_cntr: true if "mbm_event" counter assignment mode is enabled and it + * is an MBM event. * @err: Error encountered when reading counter. * @val: Returned value of event counter. If @rgrp is a parent resource group, * @val includes the sum of event counts from its child resource groups. @@ -125,6 +127,7 @@ struct rmid_read { enum resctrl_event_id evtid; bool first; struct cacheinfo *ci; + bool is_mbm_cntr; int err; u64 val; void *arch_mon_ctx; diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c index c815153cad074..55327056596ee 100644 --- a/fs/resctrl/monitor.c +++ b/fs/resctrl/monitor.c @@ -419,12 +419,24 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr) u32 closid = rdtgrp->closid; u32 rmid = rdtgrp->mon.rmid; struct rdt_mon_domain *d; + int cntr_id = -ENOENT; struct mbm_state *m; int err, ret; u64 tval = 0; + if (rr->is_mbm_cntr) { + cntr_id = mbm_cntr_get(rr->r, rr->d, rdtgrp, rr->evtid); + if (cntr_id < 0) { + rr->err = -ENOENT; + return -EINVAL; + } + } + if (rr->first) { - resctrl_arch_reset_rmid(rr->r, rr->d, closid, rmid, rr->evtid); + if (rr->is_mbm_cntr) + resctrl_arch_reset_cntr(rr->r, rr->d, closid, rmid, cntr_id, rr->evtid); + else + resctrl_arch_reset_rmid(rr->r, rr->d, closid, rmid, rr->evtid); m = get_mbm_state(rr->d, closid, rmid, rr->evtid); if (m) memset(m, 0, sizeof(struct mbm_state)); @@ -435,8 +447,12 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr) /* Reading a single domain, must be on a CPU in that domain. */ if (!cpumask_test_cpu(cpu, &rr->d->hdr.cpu_mask)) return -EINVAL; - rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid, - rr->evtid, &tval, rr->arch_mon_ctx); + if (rr->is_mbm_cntr) + rr->err = resctrl_arch_cntr_read(rr->r, rr->d, closid, rmid, cntr_id, + rr->evtid, &tval); + else + rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid, + rr->evtid, &tval, rr->arch_mon_ctx); if (rr->err) return rr->err; @@ -460,8 +476,12 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr) list_for_each_entry(d, &rr->r->mon_domains, hdr.list) { if (d->ci_id != rr->ci->id) continue; - err = resctrl_arch_rmid_read(rr->r, d, closid, rmid, - rr->evtid, &tval, rr->arch_mon_ctx); + if (rr->is_mbm_cntr) + err = resctrl_arch_cntr_read(rr->r, d, closid, rmid, cntr_id, + rr->evtid, &tval); + else + err = resctrl_arch_rmid_read(rr->r, d, closid, rmid, + rr->evtid, &tval, rr->arch_mon_ctx); if (!err) { rr->val += tval; ret = 0; @@ -668,11 +688,15 @@ static void mbm_update_one_event(struct rdt_resource *r, struct rdt_mon_domain * rr.r = r; rr.d = d; rr.evtid = evtid; - rr.arch_mon_ctx = resctrl_arch_mon_ctx_alloc(rr.r, rr.evtid); - if (IS_ERR(rr.arch_mon_ctx)) { - pr_warn_ratelimited("Failed to allocate monitor context: %ld", - PTR_ERR(rr.arch_mon_ctx)); - return; + if (resctrl_arch_mbm_cntr_assign_enabled(r)) { + rr.is_mbm_cntr = true; + } else { + rr.arch_mon_ctx = resctrl_arch_mon_ctx_alloc(rr.r, rr.evtid); + if (IS_ERR(rr.arch_mon_ctx)) { + pr_warn_ratelimited("Failed to allocate monitor context: %ld", + PTR_ERR(rr.arch_mon_ctx)); + return; + } } __mon_event_count(rdtgrp, &rr); @@ -684,7 +708,8 @@ static void mbm_update_one_event(struct rdt_resource *r, struct rdt_mon_domain * if (is_mba_sc(NULL)) mbm_bw_count(rdtgrp, &rr); - resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx); + if (rr.arch_mon_ctx) + resctrl_arch_mon_ctx_free(rr.r, rr.evtid, rr.arch_mon_ctx); } static void mbm_update(struct rdt_resource *r, struct rdt_mon_domain *d,