linux-kernel - [PATCH V2 06/10] x86/resctrl: Introduce utility to return pseudo-locked cache portion

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Date:   Tue, 30 Jul 2019 10:29:40 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     tglx@...utronix.de, fenghua.yu@...el.com, bp@...en8.de,
        tony.luck@...el.com
Cc:     kuo-lang.tseng@...el.com, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        Reinette Chatre <reinette.chatre@...el.com>
Subject: [PATCH V2 06/10] x86/resctrl: Introduce utility to return pseudo-locked cache portion

To prevent eviction of pseudo-locked memory it is required that no
other resource group uses any portion of a cache that is in use by
a cache pseudo-locked region.

Introduce a utility that will return a Capacity BitMask (CBM) indicating
all portions of a provided cache instance being used for cache
pseudo-locking. This CBM can be used in overlap checking as well as
cache usage reporting.

Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>
---
 arch/x86/kernel/cpu/resctrl/internal.h    |  1 +
 arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 65f558a2e806..f17633cf4776 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -568,6 +568,7 @@ int rdtgroup_tasks_assigned(struct rdtgroup *r);
 int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
 int rdtgroup_locksetup_exit(struct rdtgroup *rdtgrp);
 bool rdtgroup_cbm_overlaps_pseudo_locked(struct rdt_domain *d, unsigned long cbm);
+u32 rdtgroup_pseudo_locked_bits(struct rdt_resource *r, struct rdt_domain *d);
 bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_domain *d);
 int rdt_pseudo_lock_init(void);
 void rdt_pseudo_lock_release(void);
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index e7d1fdd76161..f16702a076a3 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -1626,3 +1626,26 @@ void rdt_pseudo_lock_release(void)
 	unregister_chrdev(pseudo_lock_major, "pseudo_lock");
 	pseudo_lock_major = 0;
 }
+
+/**
+ * rdt_pseudo_locked_bits - Portions of cache instance used for pseudo-locking
+ * @r:		RDT resource to which cache instance belongs
+ * @d:		Cache instance
+ *
+ * Return: bits in CBM of @d that are used for cache pseudo-locking
+ */
+u32 rdtgroup_pseudo_locked_bits(struct rdt_resource *r, struct rdt_domain *d)
+{
+	struct rdtgroup *rdtgrp;
+	u32 pseudo_locked = 0;
+
+	list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
+		if (!rdtgrp->plr)
+			continue;
+		if (rdtgrp->plr->r && rdtgrp->plr->r->rid == r->rid &&
+		    rdtgrp->plr->d_id == d->id)
+			pseudo_locked |= rdtgrp->plr->cbm;
+	}
+
+	return pseudo_locked;
+}
-- 
2.17.2