linux-kernel - Re: [PATCH v5 16/20] x86/resctrl: Report "Unassigned" for MBM events in ABMC mode

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Message-ID: <e194e550-e7e5-4df6-bda1-eb1141777ce5@web.de>
Date: Sat, 13 Jul 2024 22:26:21 +0200
From: Markus Elfring <Markus.Elfring@....de>
To: Babu Moger <babu.moger@....com>, x86@...nel.org,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 Fenghua Yu <fenghua.yu@...el.com>, Ingo Molnar <mingo@...hat.com>,
 Jonathan Corbet <corbet@....net>, Reinette Chatre
 <reinette.chatre@...el.com>, Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>, linux-doc@...r.kernel.org,
 Breno Leitao <leitao@...ian.org>,
 Daniel Sneddon <daniel.sneddon@...ux.intel.com>,
 "H. Peter Anvin" <hpa@...or.com>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 James Morse <james.morse@....com>, Jim Mattson <jmattson@...gle.com>,
 Jithu Joseph <jithu.joseph@...el.com>, Josh Poimboeuf <jpoimboe@...nel.org>,
 Julia Lawall <julia.lawall@...ia.fr>, Kai Huang <kai.huang@...el.com>,
 Kan Liang <kan.liang@...ux.intel.com>, Kim Phillips <kim.phillips@....com>,
 Lukas Bulwahn <lukas.bulwahn@...il.com>,
 Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
 Paolo Bonzini <pbonzini@...hat.com>, "Paul E. McKenney"
 <paulmck@...nel.org>, Peter Newman <peternewman@...gle.com>,
 Peter Zijlstra <peterz@...radead.org>, Randy Dunlap <rdunlap@...radead.org>,
 Rick Edgecombe <rick.p.edgecombe@...el.com>,
 Sandipan Das <sandipan.das@....com>, Sean Christopherson
 <seanjc@...gle.com>, Stephane Eranian <eranian@...gle.com>,
 Tejun Heo <tj@...nel.org>, Yan-Jie Wang <yanjiewtw@...il.com>
Subject: Re: [PATCH v5 16/20] x86/resctrl: Report "Unassigned" for MBM events
 in ABMC mode

…
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
…
> @@ -609,12 +609,21 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
…
+		if (resctrl_arch_get_abmc_enabled()) {
+			index = mon_event_config_index_get(evtid);
+			if (rdtgrp->mon.cntr_id[index] == MON_CNTR_UNSET)
+				seq_puts(m, "Unassigned\n");
+			else
+				seq_puts(m, "Unavailable\n");
+		} else {
…

I suggest to restrict the scope for the shown local variable to this if branch.

How do you think about to apply a code variant like the following?

			int index = mon_event_config_index_get(evtid);

			seq_puts(m,
				 (rdtgrp->mon.cntr_id[index] == MON_CNTR_UNSET
				 ? "Unassigned\n"
                                 : "Unavailable\n") );

Regards,
Markus