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Date: Thu, 10 May 2012 13:00:13 +0800
From: Alex Shi <alex.shi@...el.com>
To: rob@...dley.net, tglx@...utronix.de, mingo@...hat.com,
hpa@...or.com, arnd@...db.de, rostedt@...dmis.org,
fweisbec@...il.com
Cc: jeremy@...p.org, gregkh@...uxfoundation.org,
borislav.petkov@....com, alex.shi@...el.com, riel@...hat.com,
luto@....edu, avi@...hat.com, len.brown@...el.com,
dhowells@...hat.com, fenghua.yu@...el.com, ak@...ux.intel.com,
cpw@....com, steiner@....com, akpm@...ux-foundation.org,
penberg@...nel.org, hughd@...gle.com, rientjes@...gle.com,
kosaki.motohiro@...fujitsu.com, n-horiguchi@...jp.nec.com,
paul.gortmaker@...driver.com, trenn@...e.de, tj@...nel.org,
oleg@...hat.com, axboe@...nel.dk, a.p.zijlstra@...llo.nl,
kamezawa.hiroyu@...fujitsu.com, viro@...iv.linux.org.uk,
linux-kernel@...r.kernel.org
Subject: [PATCH v4 7/7] x86/tlb: add tlb_flushall_factor into sysfs for user testing/tuning
kernel will replace cr3 rewrite with invlpg when
tlb_flush_entries <= active_tlb_entries / 2^tlb_flushall_factor
if tlb_flushall_factor is -1, kernel won't do this replacement.
User can modify its value according to specific applications.
Signed-off-by: Alex Shi <alex.shi@...el.com>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 12 ++++++
arch/x86/Kconfig.debug | 11 ++++++
arch/x86/kernel/cpu/common.c | 37 ++++++++++++++++++++
drivers/base/cpu.c | 4 ++
include/linux/cpu.h | 4 ++
5 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index e7be75b..05f8eb7 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -78,6 +78,18 @@ Description: Dynamic addition and removal of CPU's. This is not hotplug
the system. Information writtento the file to remove CPU's
is architecture specific.
+What: /sys/devices/system/cpu/tlb_flushall_factor
+Date: May 2012
+Contact: Linux kernel mailing list <linux-kernel@...r.kernel.org>
+Description: tlb_flushall_factor show and setting interface
+ tlb_flushall_factor shows the balance point in replacing cr3
+ writting with multiple 'invlpg'. It will do this replacement
+ when flush_tlb_lines <= active_lines/2^tlb_flushall_factor
+ If tlb_flushall_factor is -1, means the replacement will be
+ disabled.
+
+ User can set this for the specific CPU or application.
+
What: /sys/devices/system/cpu/cpu#/node
Date: October 2009
Contact: Linux memory management mailing list <linux-mm@...ck.org>
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index e46c214..5b87493 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -129,6 +129,17 @@ config DOUBLEFAULT
option saves about 4k and might cause you much additional grey
hair.
+config DEBUG_TLBFLUSH
+ bool "Enable user level tlb flush all setting"
+ depends on DEBUG_KERNEL && (X86_64 || X86_INVLPG)
+ ---help---
+ This option allows user tune tlb_flushall_factor knob that under
+ /sys/devices/system/cpu, set to -1 means do tlb flush all for any
+ multiple tlb lines evacuation demand. Otherwise kernel will use
+ multiple 'invlpg' for the demand when
+ flush_lines <= active_tlb_lines / 2^tlb_flushall_factor
+ If in doubt, say "N"
+
config IOMMU_DEBUG
bool "Enable IOMMU debugging"
depends on GART_IOMMU && DEBUG_KERNEL
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8879d20..d1986c6 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -481,6 +481,43 @@ void __cpuinit cpu_detect_tlb(struct cpuinfo_x86 *c)
tlb_flushall_factor);
}
+#ifdef CONFIG_DEBUG_TLBFLUSH
+static ssize_t __tlb_flushall_factor_store(const char *buf,
+ size_t count, int smt)
+{
+ short factor = 0;
+
+ if (sscanf(buf, "%hd", &factor) != 1)
+ return -EINVAL;
+
+ tlb_flushall_factor = factor;
+
+ return count;
+}
+
+static ssize_t tlb_flushall_factor_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%hd\n", tlb_flushall_factor);
+}
+static ssize_t tlb_flushall_factor_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ return __tlb_flushall_factor_store(buf, count, 0);
+}
+
+static DEVICE_ATTR(tlb_flushall_factor, 0644,
+ tlb_flushall_factor_show,
+ tlb_flushall_factor_store);
+
+int __init create_sysfs_tlb_flushall_factor(struct device *dev)
+{
+ return device_create_file(dev, &dev_attr_tlb_flushall_factor);
+}
+#endif
+
void __cpuinit detect_ht(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_HT
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index adf937b..dc0f77b 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -331,6 +331,10 @@ void __init cpu_dev_init(void)
cpu_dev_register_generic();
+#ifdef CONFIG_DEBUG_TLBFLUSH
+ create_sysfs_tlb_flushall_factor(cpu_subsys.dev_root);
+#endif
+
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
sched_create_sysfs_power_savings_entries(cpu_subsys.dev_root);
#endif
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index ee28844..3eb85a5 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -36,6 +36,10 @@ extern void cpu_remove_dev_attr(struct device_attribute *attr);
extern int cpu_add_dev_attr_group(struct attribute_group *attrs);
extern void cpu_remove_dev_attr_group(struct attribute_group *attrs);
+#ifdef CONFIG_DEBUG_TLBFLUSH
+extern int create_sysfs_tlb_flushall_factor(struct device *dev);
+#endif
+
extern int sched_create_sysfs_power_savings_entries(struct device *dev);
#ifdef CONFIG_HOTPLUG_CPU
--
1.7.5.4
--
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