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Date: Thu, 1 Oct 2015 23:09:40 -0700
From: Fenghua Yu <fenghua.yu@...el.com>
To: "H Peter Anvin" <hpa@...or.com>, "Ingo Molnar" <mingo@...hat.com>,
"Thomas Gleixner" <tglx@...utronix.de>,
"Peter Zijlstra" <peterz@...radead.org>
Cc: "linux-kernel" <linux-kernel@...r.kernel.org>,
"x86" <x86@...nel.org>, "Fenghua Yu" <fenghua.yu@...el.com>,
"Vikas Shivappa" <vikas.shivappa@...ux.intel.com>
Subject: [PATCH V15 06/11] x86/intel_rdt: Add L3 cache capacity bitmask management
This patch adds different APIs to manage the L3 cache capacity bitmask.
The capacity bit mask(CBM) needs to have only contiguous bits set. The
current implementation has a global CBM for each class of service id.
There are APIs added to update the CBM via MSR write to IA32_L3_MASK_n
on all packages. Other APIs are to read and write entries to the
clos_cbm_table.
Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
---
arch/x86/include/asm/intel_rdt.h | 4 ++
arch/x86/kernel/cpu/intel_rdt.c | 133 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 136 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index 88b7643..4f45dc8 100644
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -3,6 +3,10 @@
#ifdef CONFIG_INTEL_RDT
+#define MAX_CBM_LENGTH 32
+#define IA32_L3_CBM_BASE 0xc90
+#define CBM_FROM_INDEX(x) (IA32_L3_CBM_BASE + x)
+
struct clos_cbm_table {
unsigned long l3_cbm;
unsigned int clos_refcnt;
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index d79213a..6ad5b48 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -34,8 +34,22 @@ static struct clos_cbm_table *cctable;
* closid availability bit map.
*/
unsigned long *closmap;
+/*
+ * Mask of CPUs for writing CBM values. We only need one CPU per-socket.
+ */
+static cpumask_t rdt_cpumask;
+/*
+ * Temporary cpumask used during hot cpu notificaiton handling. The usage
+ * is serialized by hot cpu locks.
+ */
+static cpumask_t tmp_cpumask;
static DEFINE_MUTEX(rdt_group_mutex);
+struct rdt_remote_data {
+ int msr;
+ u64 val;
+};
+
static inline void closid_get(u32 closid)
{
struct clos_cbm_table *cct = &cctable[closid];
@@ -82,11 +96,126 @@ static void closid_put(u32 closid)
closid_free(closid);
}
+static bool cbm_validate(unsigned long var)
+{
+ u32 max_cbm_len = boot_cpu_data.x86_cache_max_cbm_len;
+ unsigned long first_bit, zero_bit;
+ u64 max_cbm;
+
+ if (bitmap_weight(&var, max_cbm_len) < 1)
+ return false;
+
+ max_cbm = (1ULL << max_cbm_len) - 1;
+ if (var & ~max_cbm)
+ return false;
+
+ first_bit = find_first_bit(&var, max_cbm_len);
+ zero_bit = find_next_zero_bit(&var, max_cbm_len, first_bit);
+
+ if (find_next_bit(&var, max_cbm_len, zero_bit) < max_cbm_len)
+ return false;
+
+ return true;
+}
+
+static int clos_cbm_table_read(u32 closid, unsigned long *l3_cbm)
+{
+ u32 maxid = boot_cpu_data.x86_cache_max_closid;
+
+ lockdep_assert_held(&rdt_group_mutex);
+
+ if (closid >= maxid)
+ return -EINVAL;
+
+ *l3_cbm = cctable[closid].l3_cbm;
+
+ return 0;
+}
+
+/*
+ * clos_cbm_table_update() - Update a clos cbm table entry.
+ * @closid: the closid whose cbm needs to be updated
+ * @cbm: the new cbm value that has to be updated
+ *
+ * This assumes the cbm is validated as per the interface requirements
+ * and the cache allocation requirements(through the cbm_validate).
+ */
+static int clos_cbm_table_update(u32 closid, unsigned long cbm)
+{
+ u32 maxid = boot_cpu_data.x86_cache_max_closid;
+
+ lockdep_assert_held(&rdt_group_mutex);
+
+ if (closid >= maxid)
+ return -EINVAL;
+
+ cctable[closid].l3_cbm = cbm;
+
+ return 0;
+}
+
+static bool cbm_search(unsigned long cbm, u32 *closid)
+{
+ u32 maxid = boot_cpu_data.x86_cache_max_closid;
+ u32 i;
+
+ for (i = 0; i < maxid; i++) {
+ if (cctable[i].clos_refcnt &&
+ bitmap_equal(&cbm, &cctable[i].l3_cbm, MAX_CBM_LENGTH)) {
+ *closid = i;
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static void closcbm_map_dump(void)
+{
+ u32 i;
+
+ pr_debug("CBMMAP\n");
+ for (i = 0; i < boot_cpu_data.x86_cache_max_closid; i++) {
+ pr_debug("l3_cbm: 0x%x,clos_refcnt: %u\n",
+ (unsigned int)cctable[i].l3_cbm, cctable[i].clos_refcnt);
+ }
+}
+
+static void msr_cpu_update(void *arg)
+{
+ struct rdt_remote_data *info = arg;
+
+ wrmsrl(info->msr, info->val);
+}
+
+/*
+ * msr_update_all() - Update the msr for all packages.
+ */
+static inline void msr_update_all(int msr, u64 val)
+{
+ struct rdt_remote_data info;
+
+ info.msr = msr;
+ info.val = val;
+ on_each_cpu_mask(&rdt_cpumask, msr_cpu_update, &info, 1);
+}
+
+static inline bool rdt_cpumask_update(int cpu)
+{
+ cpumask_and(&tmp_cpumask, &rdt_cpumask, topology_core_cpumask(cpu));
+ if (cpumask_empty(&tmp_cpumask)) {
+ cpumask_set_cpu(cpu, &rdt_cpumask);
+ return true;
+ }
+
+ return false;
+}
+
static int __init intel_rdt_late_init(void)
{
struct cpuinfo_x86 *c = &boot_cpu_data;
u32 maxid, max_cbm_len;
- int err = 0, size;
+ int err = 0, size, i;
if (!cpu_has(c, X86_FEATURE_CAT_L3))
return -ENODEV;
@@ -109,6 +238,8 @@ static int __init intel_rdt_late_init(void)
goto out_err;
}
+ for_each_online_cpu(i)
+ rdt_cpumask_update(i);
pr_info("Intel cache allocation enabled\n");
out_err:
--
1.8.1.2
--
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