linux-kernel - [RFC PATCH v3 08/17] x86/resctrl: Initialize assignable counters bitmap

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Message-ID: <d9fe6638d901791dfdec26caed034179c636e17b.1711674410.git.babu.moger@amd.com>
Date: Thu, 28 Mar 2024 20:06:41 -0500
From: Babu Moger <babu.moger@....com>
To: <corbet@....net>, <fenghua.yu@...el.com>, <reinette.chatre@...el.com>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
	<rdunlap@...radead.org>, <tj@...nel.org>, <peterz@...radead.org>,
	<yanjiewtw@...il.com>, <babu.moger@....com>, <kim.phillips@....com>,
	<lukas.bulwahn@...il.com>, <seanjc@...gle.com>, <jmattson@...gle.com>,
	<leitao@...ian.org>, <jpoimboe@...nel.org>, <rick.p.edgecombe@...el.com>,
	<kirill.shutemov@...ux.intel.com>, <jithu.joseph@...el.com>,
	<kai.huang@...el.com>, <kan.liang@...ux.intel.com>,
	<daniel.sneddon@...ux.intel.com>, <pbonzini@...hat.com>,
	<sandipan.das@....com>, <ilpo.jarvinen@...ux.intel.com>,
	<peternewman@...gle.com>, <maciej.wieczor-retman@...el.com>,
	<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<eranian@...gle.com>, <james.morse@....com>
Subject: [RFC PATCH v3 08/17] x86/resctrl: Initialize assignable counters bitmap

AMD Hardware provides a set of counters when the ABMC feature is supported.
These counters are used for assigning events to the resctrl group.

Introduce the bitmap assign_cntrs_free_map to allocate and free the
counters.

Signed-off-by: Babu Moger <babu.moger@....com>

---
v3: Changed the bitmap name to assign_cntrs_free_map. Removed abmc
    from the name.

v2: Changed the bitmap name to assignable_counter_free_map from
    abmc_counter_free_map.
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index f49073c86884..2c7583e7b541 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -186,6 +186,22 @@ bool closid_allocated(unsigned int closid)
 	return !test_bit(closid, &closid_free_map);
 }
 
+static u64 assign_cntrs_free_map;
+static u32 assign_cntrs_free_map_len;
+
+static void assign_cntrs_init(void)
+{
+	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+
+	if (r->mbm_assign_cntrs > 64) {
+		r->mbm_assign_cntrs = 64;
+		WARN(1, "Cannot support more than 64 Assignable counters\n");
+	}
+
+	assign_cntrs_free_map = BIT_MASK(r->mbm_assign_cntrs) - 1;
+	assign_cntrs_free_map_len = r->mbm_assign_cntrs;
+}
+
 /**
  * rdtgroup_mode_by_closid - Return mode of resource group with closid
  * @closid: closid if the resource group
@@ -2459,6 +2475,9 @@ static int resctrl_abmc_setup(enum resctrl_res_level l, bool enable)
 	struct rdt_resource *r = &rdt_resources_all[l].r_resctrl;
 	struct rdt_domain *d;
 
+	/* Reset the counters bitmap */
+	assign_cntrs_init();
+
 	/* Update QOS_CFG MSR on all the CPUs in cpu_mask */
 	list_for_each_entry(d, &r->domains, list) {
 		on_each_cpu_mask(&d->cpu_mask, resctrl_abmc_msrwrite, &enable, 1);
-- 
2.34.1