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From: Reinette Chatre <reinette.chatre@intel.com>
To: tglx@linutronix.de, fenghua.yu@intel.com, tony.luck@intel.com,
	vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com, jithu.joseph@intel.com,
	dave.hansen@intel.com, mingo@redhat.com, hpa@zytor.com,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Reinette Chatre <reinette.chatre@intel.com>
Subject: [PATCH V4 09/38] x86/intel_rdt: Enable setting of exclusive mode
Date: Tue, 22 May 2018 04:28:57 -0700	[thread overview]
Message-ID: <de6b02cb2da65d3abd492ad115ed9813940869a1.1526987654.git.reinette.chatre@intel.com> (raw)
In-Reply-To: <cover.1526987654.git.reinette.chatre@intel.com>
In-Reply-To: <cover.1526987654.git.reinette.chatre@intel.com>

The new "mode" file now accepts "exclusive" that means that the
allocations of this resource group cannot be shared.

Enable users to modify a resource group's mode to "exclusive". To
succeed it is required that there is no overlap between resource group's
current schemata and that of all the other active resource groups as
well as cache regions potentially used by other hardware entities.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 97 +++++++++++++++++++++++++++++++-
 1 file changed, 96 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 739b1ecc2b80..3701b1cb0f73 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -812,6 +812,93 @@ static int rdtgroup_mode_show(struct kernfs_open_file *of,
 	return 0;
 }
 
+/**
+ * rdtgroup_cbm_overlaps - Does CBM for intended closid overlap with other
+ * @r: Resource to which domain instance @d belongs.
+ * @d: The domain instance for which @closid is being tested.
+ * @cbm: Capacity bitmask being tested.
+ * @closid: Intended closid for @cbm.
+ * @exclusive: Only check if overlaps with exclusive resource groups
+ *
+ * Checks if provided @cbm intended to be used for @closid on domain
+ * @d overlaps with any other closids or other hardware usage associated
+ * with this domain. If @exclusive is true then only overlaps with
+ * resource groups in exclusive mode will be considered. If @exclusive
+ * is false then overlaps with any resource group or hardware entities
+ * will be considered.
+ *
+ * Return: false if CBM does not overlap, true if it does.
+ */
+static bool rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
+				  u32 _cbm, int closid, bool exclusive)
+{
+	unsigned long *cbm = (unsigned long *)&_cbm;
+	unsigned long *ctrl_b;
+	enum rdtgrp_mode mode;
+	u32 *ctrl;
+	int i;
+
+	/* Check for any overlap with regions used by hardware directly */
+	if (!exclusive) {
+		if (bitmap_intersects(cbm,
+				      (unsigned long *)&r->cache.shareable_bits,
+				      r->cache.cbm_len))
+			return true;
+	}
+
+	/* Check for overlap with other resource groups */
+	ctrl = d->ctrl_val;
+	for (i = 0; i < r->num_closid; i++, ctrl++) {
+		ctrl_b = (unsigned long *)ctrl;
+		if (closid_allocated(i) && i != closid) {
+			if (bitmap_intersects(cbm, ctrl_b, r->cache.cbm_len)) {
+				mode = rdtgroup_mode_by_closid(i);
+				if (exclusive) {
+					if (mode == RDT_MODE_EXCLUSIVE)
+						return true;
+					continue;
+				}
+				return true;
+			}
+		}
+	}
+
+	return false;
+}
+
+/**
+ * rdtgroup_mode_test_exclusive - Test if this resource group can be exclusive
+ *
+ * An exclusive resource group implies that there should be no sharing of
+ * its allocated resources. At the time this group is considered to be
+ * exclusive this test can determine if its current schemata supports this
+ * setting by testing for overlap with all other resource groups.
+ *
+ * Return: true if resource group can be exclusive, false if there is overlap
+ * with allocations of other resource groups and thus this resource group
+ * cannot be exclusive.
+ */
+static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
+{
+	int closid = rdtgrp->closid;
+	struct rdt_resource *r;
+	struct rdt_domain *d;
+
+	for_each_alloc_enabled_rdt_resource(r) {
+		list_for_each_entry(d, &r->domains, list) {
+			if (rdtgroup_cbm_overlaps(r, d, d->ctrl_val[closid],
+						  rdtgrp->closid, false))
+				return false;
+		}
+	}
+
+	return true;
+}
+
+/**
+ * rdtgroup_mode_write - Modify the resource group's mode
+ *
+ */
 static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
 				   char *buf, size_t nbytes, loff_t off)
 {
@@ -834,11 +921,19 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
 
 	mode = rdtgrp->mode;
 
-	if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE))
+	if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE) ||
+	    (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE))
 		goto out;
 
 	if (!strcmp(buf, "shareable")) {
 		rdtgrp->mode = RDT_MODE_SHAREABLE;
+	} else if (!strcmp(buf, "exclusive")) {
+		if (!rdtgroup_mode_test_exclusive(rdtgrp)) {
+			rdt_last_cmd_printf("schemata overlaps\n");
+			ret = -EINVAL;
+			goto out;
+		}
+		rdtgrp->mode = RDT_MODE_EXCLUSIVE;
 	} else {
 		rdt_last_cmd_printf("unknown/unsupported mode\n");
 		ret = -EINVAL;
-- 
2.13.6

  parent reply	other threads:[~2018-05-22 19:37 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-22 11:28 [PATCH V4 00/38] Intel(R) Resource Director Technology Cache Pseudo-Locking enabling Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 01/38] x86/intel_rdt: Document new mode, size, and bit_usage Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 02/38] x86/intel_rdt: Introduce RDT resource group mode Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 03/38] x86/intel_rdt: Associate mode with each RDT resource group Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 04/38] x86/intel_rdt: Introduce resource group's mode resctrl file Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 05/38] x86/intel_rdt: Introduce test to determine if closid is in use Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 06/38] x86/intel_rdt: Make useful functions available internally Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 07/38] x86/intel_rdt: Initialize new resource group with sane defaults Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 08/38] x86/intel_rdt: Introduce new "exclusive" mode Reinette Chatre
2018-05-22 11:28 ` Reinette Chatre [this message]
2018-05-22 11:28 ` [PATCH V4 10/38] x86/intel_rdt: Making CBM name and type more explicit Reinette Chatre
2018-05-22 11:28 ` [PATCH V4 11/38] x86/intel_rdt: Support flexible data to parsing callbacks Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 12/38] x86/intel_rdt: Ensure requested schemata respects mode Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 13/38] x86/intel_rdt: Introduce "bit_usage" to display cache allocations details Reinette Chatre
2018-05-22 21:03   ` Randy Dunlap
2018-05-22 21:09     ` Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 14/38] x86/intel_rdt: Display resource groups' allocations' size in bytes Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 15/38] x86/intel_rdt: Documentation for Cache Pseudo-Locking Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 16/38] x86/intel_rdt: Introduce the Cache Pseudo-Locking modes Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 17/38] x86/intel_rdt: Respect read and write access Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 18/38] x86/intel_rdt: Add utility to test if tasks assigned to resource group Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 19/38] x86/intel_rdt: Add utility to restrict/restore access to resctrl files Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 20/38] x86/intel_rdt: Protect against resource group changes during locking Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 21/38] x86/intel_rdt: Utilities to restrict/restore access to specific files Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 22/38] x86/intel_rdt: Add check to determine if monitoring in progress Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 23/38] x86/intel_rdt: Introduce pseudo-locked region Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 24/38] x86/intel_rdt: Support enter/exit of locksetup mode Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 25/38] x86/intel_rdt: Enable entering of pseudo-locksetup mode Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 26/38] x86/intel_rdt: Split resource group removal in two Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 27/38] x86/intel_rdt: Add utilities to test pseudo-locked region possibility Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 28/38] x86/intel_rdt: Discover supported platforms via prefetch disable bits Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 29/38] x86/intel_rdt: Pseudo-lock region creation/removal core Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 30/38] x86/intel_rdt: Support creation/removal of pseudo-locked region Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 31/38] x86/intel_rdt: resctrl files reflect pseudo-locked information Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 32/38] x86/intel_rdt: Ensure RDT cleanup on exit Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 33/38] x86/intel_rdt: Create resctrl debug area Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 34/38] x86/intel_rdt: Create debugfs files for pseudo-locking testing Reinette Chatre
2018-05-22 19:43   ` Greg KH
2018-05-22 21:02     ` Reinette Chatre
2018-05-23  8:05       ` Greg KH
2018-05-23 17:19         ` Reinette Chatre
2018-05-23 17:27           ` Greg KH
2018-05-22 11:29 ` [PATCH V4 35/38] x86/intel_rdt: Create character device exposing pseudo-locked region Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 36/38] x86/intel_rdt: More precise L2 hit/miss measurements Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 37/38] x86/intel_rdt: Support L3 cache performance event of Broadwell Reinette Chatre
2018-05-22 11:29 ` [PATCH V4 38/38] x86/intel_rdt: Limit C-states dynamically when pseudo-locking active Reinette Chatre

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