diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-bdi | 4 | ||||
| -rw-r--r-- | Documentation/DocBook/kernel-locking.tmpl | 25 | ||||
| -rw-r--r-- | Documentation/cpu-freq/governors.txt | 8 | ||||
| -rw-r--r-- | Documentation/hwmon/ibmaem | 37 |
4 files changed, 66 insertions, 8 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index 5ac1e01bbd4..5f500977b42 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -14,6 +14,10 @@ MAJOR:MINOR non-block filesystems which provide their own BDI, such as NFS and FUSE. +MAJOR:MINOR-fuseblk + + Value of st_dev on fuseblk filesystems. + default The default backing dev, used for non-block device backed diff --git a/Documentation/DocBook/kernel-locking.tmpl b/Documentation/DocBook/kernel-locking.tmpl index 77c42f40be5..2510763295d 100644 --- a/Documentation/DocBook/kernel-locking.tmpl +++ b/Documentation/DocBook/kernel-locking.tmpl @@ -703,6 +703,31 @@ </sect1> </chapter> +<chapter id="trylock-functions"> + <title>The trylock Functions</title> + <para> + There are functions that try to acquire a lock only once and immediately + return a value telling about success or failure to acquire the lock. + They can be used if you need no access to the data protected with the lock + when some other thread is holding the lock. You should acquire the lock + later if you then need access to the data protected with the lock. + </para> + + <para> + <function>spin_trylock()</function> does not spin but returns non-zero if + it acquires the spinlock on the first try or 0 if not. This function can + be used in all contexts like <function>spin_lock</function>: you must have + disabled the contexts that might interrupt you and acquire the spin lock. + </para> + + <para> + <function>mutex_trylock()</function> does not suspend your task + but returns non-zero if it could lock the mutex on the first try + or 0 if not. This function cannot be safely used in hardware or software + interrupt contexts despite not sleeping. + </para> +</chapter> + <chapter id="Examples"> <title>Common Examples</title> <para> diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt index 6a9c55bd556..dcec0564d04 100644 --- a/Documentation/cpu-freq/governors.txt +++ b/Documentation/cpu-freq/governors.txt @@ -129,14 +129,6 @@ to its default value of '80' it means that between the checking intervals the CPU needs to be on average more than 80% in use to then decide that the CPU frequency needs to be increased. -sampling_down_factor: this parameter controls the rate that the CPU -makes a decision on when to decrease the frequency. When set to its -default value of '5' it means that at 1/5 the sampling_rate the kernel -makes a decision to lower the frequency. Five "lower rate" decisions -have to be made in a row before the CPU frequency is actually lower. -If set to '1' then the frequency decreases as quickly as it increases, -if set to '2' it decreases at half the rate of the increase. - ignore_nice_load: this parameter takes a value of '0' or '1'. When set to '0' (its default), all processes are counted towards the 'cpu utilisation' value. When set to '1', the processes that are diff --git a/Documentation/hwmon/ibmaem b/Documentation/hwmon/ibmaem new file mode 100644 index 00000000000..2fefaf582a4 --- /dev/null +++ b/Documentation/hwmon/ibmaem @@ -0,0 +1,37 @@ +Kernel driver ibmaem +====================== + +Supported systems: + * Any recent IBM System X server with Active Energy Manager support. + This includes the x3350, x3550, x3650, x3655, x3755, x3850 M2, + x3950 M2, and certain HS2x/LS2x/QS2x blades. The IPMI host interface + driver ("ipmi-si") needs to be loaded for this driver to do anything. + Prefix: 'ibmaem' + Datasheet: Not available + +Author: Darrick J. Wong + +Description +----------- + +This driver implements sensor reading support for the energy and power +meters available on various IBM System X hardware through the BMC. All +sensor banks will be exported as platform devices; this driver can talk +to both v1 and v2 interfaces. This driver is completely separate from the +older ibmpex driver. + +The v1 AEM interface has a simple set of features to monitor energy use. +There is a register that displays an estimate of raw energy consumption +since the last BMC reset, and a power sensor that returns average power +use over a configurable interval. + +The v2 AEM interface is a bit more sophisticated, being able to present +a wider range of energy and power use registers, the power cap as +set by the AEM software, and temperature sensors. + +Special Features +---------------- + +The "power_cap" value displays the current system power cap, as set by +the Active Energy Manager software. Setting the power cap from the host +is not currently supported. |