path: root/Documentation
diff options
Diffstat (limited to 'Documentation')
4 files changed, 126 insertions, 39 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index 4d4a644b505..a99d7031cdf 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -315,41 +315,26 @@ A: The following are what is required for CPU hotplug infrastructure to work
Q: I need to ensure that a particular cpu is not removed when there is some
work specific to this cpu is in progress.
-A: First switch the current thread context to preferred cpu
+A: There are two ways. If your code can be run in interrupt context, use
+ smp_call_function_single(), otherwise use work_on_cpu(). Note that
+ work_on_cpu() is slow, and can fail due to out of memory:
int my_func_on_cpu(int cpu)
- cpumask_t saved_mask, new_mask = CPU_MASK_NONE;
- int curr_cpu, err = 0;
- saved_mask = current->cpus_allowed;
- cpu_set(cpu, new_mask);
- err = set_cpus_allowed(current, new_mask);
- if (err)
- return err;
- /*
- * If we got scheduled out just after the return from
- * set_cpus_allowed() before running the work, this ensures
- * we stay locked.
- */
- curr_cpu = get_cpu();
- if (curr_cpu != cpu) {
- err = -EAGAIN;
- goto ret;
- } else {
- /*
- * Do work : But cant sleep, since get_cpu() disables preempt
- */
- }
- ret:
- put_cpu();
- set_cpus_allowed(current, saved_mask);
- return err;
- }
+ int err;
+ get_online_cpus();
+ if (!cpu_online(cpu))
+ err = -EINVAL;
+ else
+ err = work_on_cpu(cpu, __my_func_on_cpu, NULL);
+ smp_call_function_single(cpu, __my_func_on_cpu, &err,
+ true);
+ put_online_cpus();
+ return err;
+ }
Q: How do we determine how many CPUs are available for hotplug.
A: There is no clear spec defined way from ACPI that can give us that
diff --git a/Documentation/hwmon/k10temp b/Documentation/hwmon/k10temp
new file mode 100644
index 00000000000..a7a18d453a5
--- /dev/null
+++ b/Documentation/hwmon/k10temp
@@ -0,0 +1,60 @@
+Kernel driver k10temp
+Supported chips:
+* AMD Family 10h processors:
+ Socket F: Quad-Core/Six-Core/Embedded Opteron
+ Socket AM2+: Opteron, Phenom (II) X3/X4
+ Socket AM3: Quad-Core Opteron, Athlon/Phenom II X2/X3/X4, Sempron II
+ Socket S1G3: Athlon II, Sempron, Turion II
+* AMD Family 11h processors:
+ Socket S1G2: Athlon (X2), Sempron (X2), Turion X2 (Ultra)
+ Prefix: 'k10temp'
+ Addresses scanned: PCI space
+ Datasheets:
+ BIOS and Kernel Developer's Guide (BKDG) For AMD Family 10h Processors:
+ http://support.amd.com/us/Processor_TechDocs/31116.pdf
+ BIOS and Kernel Developer's Guide (BKDG) for AMD Family 11h Processors:
+ http://support.amd.com/us/Processor_TechDocs/41256.pdf
+ Revision Guide for AMD Family 10h Processors:
+ http://support.amd.com/us/Processor_TechDocs/41322.pdf
+ Revision Guide for AMD Family 11h Processors:
+ http://support.amd.com/us/Processor_TechDocs/41788.pdf
+ AMD Family 11h Processor Power and Thermal Data Sheet for Notebooks:
+ http://support.amd.com/us/Processor_TechDocs/43373.pdf
+ AMD Family 10h Server and Workstation Processor Power and Thermal Data Sheet:
+ http://support.amd.com/us/Processor_TechDocs/43374.pdf
+ AMD Family 10h Desktop Processor Power and Thermal Data Sheet:
+ http://support.amd.com/us/Processor_TechDocs/43375.pdf
+Author: Clemens Ladisch <clemens@ladisch.de>
+This driver permits reading of the internal temperature sensor of AMD
+Family 10h and 11h processors.
+All these processors have a sensor, but on older revisions of Family 10h
+processors, the sensor may return inconsistent values (erratum 319). The
+driver will refuse to load on these revisions unless you specify the
+"force=1" module parameter.
+There is one temperature measurement value, available as temp1_input in
+sysfs. It is measured in degrees Celsius with a resolution of 1/8th degree.
+Please note that it is defined as a relative value; to quote the AMD manual:
+ Tctl is the processor temperature control value, used by the platform to
+ control cooling systems. Tctl is a non-physical temperature on an
+ arbitrary scale measured in degrees. It does _not_ represent an actual
+ physical temperature like die or case temperature. Instead, it specifies
+ the processor temperature relative to the point at which the system must
+ supply the maximum cooling for the processor's specified maximum case
+ temperature and maximum thermal power dissipation.
+The maximum value for Tctl is available in the file temp1_max.
+If the BIOS has enabled hardware temperature control, the threshold at
+which the processor will throttle itself to avoid damage is available in
+temp1_crit and temp1_crit_hyst.
diff --git a/Documentation/powerpc/dts-bindings/fsl/mpic.txt b/Documentation/powerpc/dts-bindings/fsl/mpic.txt
new file mode 100644
index 00000000000..71e39cf3215
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/fsl/mpic.txt
@@ -0,0 +1,42 @@
+* OpenPIC and its interrupt numbers on Freescale's e500/e600 cores
+The OpenPIC specification does not specify which interrupt source has to
+become which interrupt number. This is up to the software implementation
+of the interrupt controller. The only requirement is that every
+interrupt source has to have an unique interrupt number / vector number.
+To accomplish this the current implementation assigns the number zero to
+the first source, the number one to the second source and so on until
+all interrupt sources have their unique number.
+Usually the assigned vector number equals the interrupt number mentioned
+in the documentation for a given core / CPU. This is however not true
+for the e500 cores (MPC85XX CPUs) where the documentation distinguishes
+between internal and external interrupt sources and starts counting at
+zero for both of them.
+So what to write for external interrupt source X or internal interrupt
+source Y into the device tree? Here is an example:
+The memory map for the interrupt controller in the MPC8544[0] shows,
+that the first interrupt source starts at 0x5_0000 (PIC Register Address
+Map-Interrupt Source Configuration Registers). This source becomes the
+number zero therefore:
+ External interrupt 0 = interrupt number 0
+ External interrupt 1 = interrupt number 1
+ External interrupt 2 = interrupt number 2
+ ...
+Every interrupt number allocates 0x20 bytes register space. So to get
+its number it is sufficient to shift the lower 16bits to right by five.
+So for the external interrupt 10 we have:
+ 0x0140 >> 5 = 10
+After the external sources, the internal sources follow. The in core I2C
+controller on the MPC8544 for instance has the internal source number
+27. Oo obtain its interrupt number we take the lower 16bits of its memory
+address (0x5_0560) and shift it right:
+ 0x0560 >> 5 = 43
+Therefore the I2C device node for the MPC8544 CPU has to have the
+interrupt number 43 specified in the device tree.
+[0] MPC8544E PowerQUICCTM III, Integrated Host Processor Family Reference Manual
+ MPC8544ERM Rev. 1 10/2007
diff --git a/Documentation/trace/events-kmem.txt b/Documentation/trace/events-kmem.txt
index 6ef2a8652e1..aa82ee4a5a8 100644
--- a/Documentation/trace/events-kmem.txt
+++ b/Documentation/trace/events-kmem.txt
@@ -1,7 +1,7 @@
Subsystem Trace Points: kmem
-The tracing system kmem captures events related to object and page allocation
-within the kernel. Broadly speaking there are four major subheadings.
+The kmem tracing system captures events related to object and page allocation
+within the kernel. Broadly speaking there are five major subheadings.
o Slab allocation of small objects of unknown type (kmalloc)
o Slab allocation of small objects of known type
@@ -9,7 +9,7 @@ within the kernel. Broadly speaking there are four major subheadings.
o Per-CPU Allocator Activity
o External Fragmentation
-This document will describe what each of the tracepoints are and why they
+This document describes what each of the tracepoints is and why they
might be useful.
1. Slab allocation of small objects of unknown type
@@ -34,7 +34,7 @@ kmem_cache_free call_site=%lx ptr=%p
These events are similar in usage to the kmalloc-related events except that
it is likely easier to pin the event down to a specific cache. At the time
of writing, no information is available on what slab is being allocated from,
-but the call_site can usually be used to extrapolate that information
+but the call_site can usually be used to extrapolate that information.
3. Page allocation
@@ -80,9 +80,9 @@ event indicating whether it is for a percpu_refill or not.
When the per-CPU list is too full, a number of pages are freed, each one
which triggers a mm_page_pcpu_drain event.
-The individual nature of the events are so that pages can be tracked
+The individual nature of the events is so that pages can be tracked
between allocation and freeing. A number of drain or refill pages that occur
-consecutively imply the zone->lock being taken once. Large amounts of PCP
+consecutively imply the zone->lock being taken once. Large amounts of per-CPU
refills and drains could imply an imbalance between CPUs where too much work
is being concentrated in one place. It could also indicate that the per-CPU
lists should be a larger size. Finally, large amounts of refills on one CPU
@@ -102,6 +102,6 @@ is important.
Large numbers of this event implies that memory is fragmenting and
high-order allocations will start failing at some time in the future. One
-means of reducing the occurange of this event is to increase the size of
+means of reducing the occurrence of this event is to increase the size of
min_free_kbytes in increments of 3*pageblock_size*nr_online_nodes where
pageblock_size is usually the size of the default hugepage size.