diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/block/queue-sysfs.txt | 18 | ||||
| -rw-r--r-- | Documentation/networking/rxrpc.txt | 21 | ||||
| -rw-r--r-- | Documentation/power/basic-pm-debugging.txt | 27 | ||||
| -rw-r--r-- | Documentation/power/interface.txt | 151 |
4 files changed, 131 insertions, 86 deletions
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index d515d58962b9..2a3904030dea 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -14,6 +14,12 @@ add_random (RW) This file allows to turn off the disk entropy contribution. Default value of this file is '1'(on). +dax (RO) +-------- +This file indicates whether the device supports Direct Access (DAX), +used by CPU-addressable storage to bypass the pagecache. It shows '1' +if true, '0' if not. + discard_granularity (RO) ----------------------- This shows the size of internal allocation of the device in bytes, if @@ -46,6 +52,12 @@ hw_sector_size (RO) ------------------- This is the hardware sector size of the device, in bytes. +io_poll (RW) +------------ +When read, this file shows the total number of block IO polls and how +many returned success. Writing '0' to this file will disable polling +for this device. Writing any non-zero value will enable this feature. + iostats (RW) ------------- This file is used to control (on/off) the iostats accounting of the @@ -151,5 +163,11 @@ device state. This means that it might not be safe to toggle the setting from "write back" to "write through", since that will also eliminate cache flushes issued by the kernel. +write_same_max_bytes (RO) +------------------------- +This is the number of bytes the device can write in a single write-same +command. A value of '0' means write-same is not supported by this +device. + Jens Axboe <jens.axboe@oracle.com>, February 2009 diff --git a/Documentation/networking/rxrpc.txt b/Documentation/networking/rxrpc.txt index 16a924c486bf..70c926ae212d 100644 --- a/Documentation/networking/rxrpc.txt +++ b/Documentation/networking/rxrpc.txt @@ -790,13 +790,12 @@ The kernel interface functions are as follows: Data messages can have their contents extracted with the usual bunch of socket buffer manipulation functions. A data message can be determined to be the last one in a sequence with rxrpc_kernel_is_data_last(). When a - data message has been used up, rxrpc_kernel_data_delivered() should be - called on it.. + data message has been used up, rxrpc_kernel_data_consumed() should be + called on it. - Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose - of. It is possible to get extra refs on all types of message for later - freeing, but this may pin the state of a call until the message is finally - freed. + Messages should be handled to rxrpc_kernel_free_skb() to dispose of. It + is possible to get extra refs on all types of message for later freeing, + but this may pin the state of a call until the message is finally freed. (*) Accept an incoming call. @@ -821,12 +820,14 @@ The kernel interface functions are as follows: Other errors may be returned if the call had been aborted (-ECONNABORTED) or had timed out (-ETIME). - (*) Record the delivery of a data message and free it. + (*) Record the delivery of a data message. - void rxrpc_kernel_data_delivered(struct sk_buff *skb); + void rxrpc_kernel_data_consumed(struct rxrpc_call *call, + struct sk_buff *skb); - This is used to record a data message as having been delivered and to - update the ACK state for the call. The socket buffer will be freed. + This is used to record a data message as having been consumed and to + update the ACK state for the call. The message must still be passed to + rxrpc_kernel_free_skb() for disposal by the caller. (*) Free a message. diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt index b96098ccfe69..708f87f78a75 100644 --- a/Documentation/power/basic-pm-debugging.txt +++ b/Documentation/power/basic-pm-debugging.txt @@ -164,7 +164,32 @@ load n/2 modules more and try again. Again, if you find the offending module(s), it(they) must be unloaded every time before hibernation, and please report the problem with it(them). -c) Advanced debugging +c) Using the "test_resume" hibernation option + +/sys/power/disk generally tells the kernel what to do after creating a +hibernation image. One of the available options is "test_resume" which +causes the just created image to be used for immediate restoration. Namely, +after doing: + +# echo test_resume > /sys/power/disk +# echo disk > /sys/power/state + +a hibernation image will be created and a resume from it will be triggered +immediately without involving the platform firmware in any way. + +That test can be used to check if failures to resume from hibernation are +related to bad interactions with the platform firmware. That is, if the above +works every time, but resume from actual hibernation does not work or is +unreliable, the platform firmware may be responsible for the failures. + +On architectures and platforms that support using different kernels to restore +hibernation images (that is, the kernel used to read the image from storage and +load it into memory is different from the one included in the image) or support +kernel address space randomization, it also can be used to check if failures +to resume may be related to the differences between the restore and image +kernels. + +d) Advanced debugging In case that hibernation does not work on your system even in the minimal configuration and compiling more drivers as modules is not practical or some diff --git a/Documentation/power/interface.txt b/Documentation/power/interface.txt index f1f0f59a7c47..974916ff6608 100644 --- a/Documentation/power/interface.txt +++ b/Documentation/power/interface.txt @@ -1,75 +1,76 @@ -Power Management Interface - - -The power management subsystem provides a unified sysfs interface to -userspace, regardless of what architecture or platform one is -running. The interface exists in /sys/power/ directory (assuming sysfs -is mounted at /sys). - -/sys/power/state controls system power state. Reading from this file -returns what states are supported, which is hard-coded to 'freeze', -'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and 'disk' -(Suspend-to-Disk). - -Writing to this file one of those strings causes the system to -transition into that state. Please see the file -Documentation/power/states.txt for a description of each of those -states. - - -/sys/power/disk controls the operating mode of the suspend-to-disk -mechanism. Suspend-to-disk can be handled in several ways. We have a -few options for putting the system to sleep - using the platform driver -(e.g. ACPI or other suspend_ops), powering off the system or rebooting the -system (for testing). - -Additionally, /sys/power/disk can be used to turn on one of the two testing -modes of the suspend-to-disk mechanism: 'testproc' or 'test'. If the -suspend-to-disk mechanism is in the 'testproc' mode, writing 'disk' to -/sys/power/state will cause the kernel to disable nonboot CPUs and freeze -tasks, wait for 5 seconds, unfreeze tasks and enable nonboot CPUs. If it is -in the 'test' mode, writing 'disk' to /sys/power/state will cause the kernel -to disable nonboot CPUs and freeze tasks, shrink memory, suspend devices, wait -for 5 seconds, resume devices, unfreeze tasks and enable nonboot CPUs. Then, -we are able to look in the log messages and work out, for example, which code -is being slow and which device drivers are misbehaving. - -Reading from this file will display all supported modes and the currently -selected one in brackets, for example - - [shutdown] reboot test testproc - -Writing to this file will accept one of - - 'platform' (only if the platform supports it) - 'shutdown' - 'reboot' - 'testproc' - 'test' - -/sys/power/image_size controls the size of the image created by -the suspend-to-disk mechanism. It can be written a string -representing a non-negative integer that will be used as an upper -limit of the image size, in bytes. The suspend-to-disk mechanism will -do its best to ensure the image size will not exceed that number. However, -if this turns out to be impossible, it will try to suspend anyway using the -smallest image possible. In particular, if "0" is written to this file, the -suspend image will be as small as possible. - -Reading from this file will display the current image size limit, which -is set to 2/5 of available RAM by default. - -/sys/power/pm_trace controls the code which saves the last PM event point in -the RTC across reboots, so that you can debug a machine that just hangs -during suspend (or more commonly, during resume). Namely, the RTC is only -used to save the last PM event point if this file contains '1'. Initially it -contains '0' which may be changed to '1' by writing a string representing a -nonzero integer into it. - -To use this debugging feature you should attempt to suspend the machine, then -reboot it and run - - dmesg -s 1000000 | grep 'hash matches' - -CAUTION: Using it will cause your machine's real-time (CMOS) clock to be -set to a random invalid time after a resume. +Power Management Interface for System Sleep + +Copyright (c) 2016 Intel Corp., Rafael J. Wysocki <rafael.j.wysocki@intel.com> + +The power management subsystem provides userspace with a unified sysfs interface +for system sleep regardless of the underlying system architecture or platform. +The interface is located in the /sys/power/ directory (assuming that sysfs is +mounted at /sys). + +/sys/power/state is the system sleep state control file. + +Reading from it returns a list of supported sleep states, encoded as: + +'freeze' (Suspend-to-Idle) +'standby' (Power-On Suspend) +'mem' (Suspend-to-RAM) +'disk' (Suspend-to-Disk) + +Suspend-to-Idle is always supported. Suspend-to-Disk is always supported +too as long the kernel has been configured to support hibernation at all +(ie. CONFIG_HIBERNATION is set in the kernel configuration file). Support +for Suspend-to-RAM and Power-On Suspend depends on the capabilities of the +platform. + +If one of the strings listed in /sys/power/state is written to it, the system +will attempt to transition into the corresponding sleep state. Refer to +Documentation/power/states.txt for a description of each of those states. + +/sys/power/disk controls the operating mode of hibernation (Suspend-to-Disk). +Specifically, it tells the kernel what to do after creating a hibernation image. + +Reading from it returns a list of supported options encoded as: + +'platform' (put the system into sleep using a platform-provided method) +'shutdown' (shut the system down) +'reboot' (reboot the system) +'suspend' (trigger a Suspend-to-RAM transition) +'test_resume' (resume-after-hibernation test mode) + +The currently selected option is printed in square brackets. + +The 'platform' option is only available if the platform provides a special +mechanism to put the system to sleep after creating a hibernation image (ACPI +does that, for example). The 'suspend' option is available if Suspend-to-RAM +is supported. Refer to Documentation/power/basic_pm_debugging.txt for the +description of the 'test_resume' option. + +To select an option, write the string representing it to /sys/power/disk. + +/sys/power/image_size controls the size of hibernation images. + +It can be written a string representing a non-negative integer that will be +used as a best-effort upper limit of the image size, in bytes. The hibernation +core will do its best to ensure that the image size will not exceed that number. +However, if that turns out to be impossible to achieve, a hibernation image will +still be created and its size will be as small as possible. In particular, +writing '0' to this file will enforce hibernation images to be as small as +possible. + +Reading from this file returns the current image size limit, which is set to +around 2/5 of available RAM by default. + +/sys/power/pm_trace controls the PM trace mechanism saving the last suspend +or resume event point in the RTC across reboots. + +It helps to debug hard lockups or reboots due to device driver failures that +occur during system suspend or resume (which is more common) more effectively. + +If /sys/power/pm_trace contains '1', the fingerprint of each suspend/resume +event point in turn will be stored in the RTC memory (overwriting the actual +RTC information), so it will survive a system crash if one occurs right after +storing it and it can be used later to identify the driver that caused the crash +to happen (see Documentation/power/s2ram.txt for more information). + +Initially it contains '0' which may be changed to '1' by writing a string +representing a nonzero integer into it. |