diff options
| author | Florian Tobias Schandinat <FlorianSchandinat@gmx.de> | 2012-10-10 02:16:30 +0000 |
|---|---|---|
| committer | Florian Tobias Schandinat <FlorianSchandinat@gmx.de> | 2012-10-10 02:16:30 +0000 |
| commit | 0febd3bccff3ac005a570180209e44fb7de188df (patch) | |
| tree | 2af5177fb8fef95900f68c64121ad6bdc78d8761 /Documentation | |
| parent | 8d93241b923bcb6a60994f8ed20fda8cc06d0fda (diff) | |
| parent | 13b1ba7de8d0ecc42e4f9c002d5b0c1a48f05e58 (diff) | |
Merge tag 'omapdss-for-3.7' of git://gitorious.org/linux-omap-dss2/linux into fbdev-next
Omapdss driver changes for the 3.7 merge window.
Notable changes:
* Basic writeback support for DISPC level. Writeback is not yet usable, though,
as we need higher level code to actually expose the writeback feature to
userspace.
* Rewriting the omapdss output drivers. We're trying to remove the hard links
between the omapdss and the panels, and this rewrite work moves us closer to
that goal.
* Cleanup and restructuring patches that have been made while working on device
tree support for omapdss. Device tree support is still some way ahead, but
these patches are good cleanups in themselves.
* Basic OMAP5 DSS support for DPI and DSI outputs.
* Workaround for the problem that GFX overlay's fifo is too small for high
resolution scenarios, causing underflows.
* Cleanups that remove dependencies to omap platform code.
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/block/00-INDEX | 10 | ||||
| -rw-r--r-- | Documentation/block/cfq-iosched.txt | 77 | ||||
| -rw-r--r-- | Documentation/block/queue-sysfs.txt | 64 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt | 8 | ||||
| -rw-r--r-- | Documentation/watchdog/src/watchdog-test.c | 2 |
5 files changed, 154 insertions, 7 deletions
diff --git a/Documentation/block/00-INDEX b/Documentation/block/00-INDEX index d111e3b23db0..d18ecd827c40 100644 --- a/Documentation/block/00-INDEX +++ b/Documentation/block/00-INDEX @@ -3,15 +3,21 @@ biodoc.txt - Notes on the Generic Block Layer Rewrite in Linux 2.5 capability.txt - - Generic Block Device Capability (/sys/block/<disk>/capability) + - Generic Block Device Capability (/sys/block/<device>/capability) +cfq-iosched.txt + - CFQ IO scheduler tunables +data-integrity.txt + - Block data integrity deadline-iosched.txt - Deadline IO scheduler tunables ioprio.txt - Block io priorities (in CFQ scheduler) +queue-sysfs.txt + - Queue's sysfs entries request.txt - The members of struct request (in include/linux/blkdev.h) stat.txt - - Block layer statistics in /sys/block/<dev>/stat + - Block layer statistics in /sys/block/<device>/stat switching-sched.txt - Switching I/O schedulers at runtime writeback_cache_control.txt diff --git a/Documentation/block/cfq-iosched.txt b/Documentation/block/cfq-iosched.txt index 6d670f570451..d89b4fe724d7 100644 --- a/Documentation/block/cfq-iosched.txt +++ b/Documentation/block/cfq-iosched.txt @@ -1,3 +1,14 @@ +CFQ (Complete Fairness Queueing) +=============================== + +The main aim of CFQ scheduler is to provide a fair allocation of the disk +I/O bandwidth for all the processes which requests an I/O operation. + +CFQ maintains the per process queue for the processes which request I/O +operation(syncronous requests). In case of asynchronous requests, all the +requests from all the processes are batched together according to their +process's I/O priority. + CFQ ioscheduler tunables ======================== @@ -25,6 +36,72 @@ there are multiple spindles behind single LUN (Host based hardware RAID controller or for storage arrays), setting slice_idle=0 might end up in better throughput and acceptable latencies. +back_seek_max +------------- +This specifies, given in Kbytes, the maximum "distance" for backward seeking. +The distance is the amount of space from the current head location to the +sectors that are backward in terms of distance. + +This parameter allows the scheduler to anticipate requests in the "backward" +direction and consider them as being the "next" if they are within this +distance from the current head location. + +back_seek_penalty +----------------- +This parameter is used to compute the cost of backward seeking. If the +backward distance of request is just 1/back_seek_penalty from a "front" +request, then the seeking cost of two requests is considered equivalent. + +So scheduler will not bias toward one or the other request (otherwise scheduler +will bias toward front request). Default value of back_seek_penalty is 2. + +fifo_expire_async +----------------- +This parameter is used to set the timeout of asynchronous requests. Default +value of this is 248ms. + +fifo_expire_sync +---------------- +This parameter is used to set the timeout of synchronous requests. Default +value of this is 124ms. In case to favor synchronous requests over asynchronous +one, this value should be decreased relative to fifo_expire_async. + +slice_async +----------- +This parameter is same as of slice_sync but for asynchronous queue. The +default value is 40ms. + +slice_async_rq +-------------- +This parameter is used to limit the dispatching of asynchronous request to +device request queue in queue's slice time. The maximum number of request that +are allowed to be dispatched also depends upon the io priority. Default value +for this is 2. + +slice_sync +---------- +When a queue is selected for execution, the queues IO requests are only +executed for a certain amount of time(time_slice) before switching to another +queue. This parameter is used to calculate the time slice of synchronous +queue. + +time_slice is computed using the below equation:- +time_slice = slice_sync + (slice_sync/5 * (4 - prio)). To increase the +time_slice of synchronous queue, increase the value of slice_sync. Default +value is 100ms. + +quantum +------- +This specifies the number of request dispatched to the device queue. In a +queue's time slice, a request will not be dispatched if the number of request +in the device exceeds this parameter. This parameter is used for synchronous +request. + +In case of storage with several disk, this setting can limit the parallel +processing of request. Therefore, increasing the value can imporve the +performace although this can cause the latency of some I/O to increase due +to more number of requests. + CFQ IOPS Mode for group scheduling =================================== Basic CFQ design is to provide priority based time slices. Higher priority diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index 6518a55273e7..e54ac1d53403 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -9,20 +9,71 @@ These files are the ones found in the /sys/block/xxx/queue/ directory. Files denoted with a RO postfix are readonly and the RW postfix means read-write. +add_random (RW) +---------------- +This file allows to trun off the disk entropy contribution. Default +value of this file is '1'(on). + +discard_granularity (RO) +----------------------- +This shows the size of internal allocation of the device in bytes, if +reported by the device. A value of '0' means device does not support +the discard functionality. + +discard_max_bytes (RO) +---------------------- +Devices that support discard functionality may have internal limits on +the number of bytes that can be trimmed or unmapped in a single operation. +The discard_max_bytes parameter is set by the device driver to the maximum +number of bytes that can be discarded in a single operation. Discard +requests issued to the device must not exceed this limit. A discard_max_bytes +value of 0 means that the device does not support discard functionality. + +discard_zeroes_data (RO) +------------------------ +When read, this file will show if the discarded block are zeroed by the +device or not. If its value is '1' the blocks are zeroed otherwise not. + hw_sector_size (RO) ------------------- This is the hardware sector size of the device, in bytes. +iostats (RW) +------------- +This file is used to control (on/off) the iostats accounting of the +disk. + +logical_block_size (RO) +----------------------- +This is the logcal block size of the device, in bytes. + max_hw_sectors_kb (RO) ---------------------- This is the maximum number of kilobytes supported in a single data transfer. +max_integrity_segments (RO) +--------------------------- +When read, this file shows the max limit of integrity segments as +set by block layer which a hardware controller can handle. + max_sectors_kb (RW) ------------------- This is the maximum number of kilobytes that the block layer will allow for a filesystem request. Must be smaller than or equal to the maximum size allowed by the hardware. +max_segments (RO) +----------------- +Maximum number of segments of the device. + +max_segment_size (RO) +--------------------- +Maximum segment size of the device. + +minimum_io_size (RO) +-------------------- +This is the smallest preferred io size reported by the device. + nomerges (RW) ------------- This enables the user to disable the lookup logic involved with IO @@ -45,11 +96,24 @@ per-block-cgroup request pool. IOW, if there are N block cgroups, each request queue may have upto N request pools, each independently regulated by nr_requests. +optimal_io_size (RO) +-------------------- +This is the optimal io size reported by the device. + +physical_block_size (RO) +------------------------ +This is the physical block size of device, in bytes. + read_ahead_kb (RW) ------------------ Maximum number of kilobytes to read-ahead for filesystems on this block device. +rotational (RW) +--------------- +This file is used to stat if the device is of rotational type or +non-rotational type. + rq_affinity (RW) ---------------- If this option is '1', the block layer will migrate request completions to the diff --git a/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt b/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt index 70cd49b1caa8..1dd622546d06 100644 --- a/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt +++ b/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt @@ -10,8 +10,8 @@ Required properties: - compatible : Should be "fsl,<chip>-esdhc" Optional properties: -- fsl,cd-internal : Indicate to use controller internal card detection -- fsl,wp-internal : Indicate to use controller internal write protection +- fsl,cd-controller : Indicate to use controller internal card detection +- fsl,wp-controller : Indicate to use controller internal write protection Examples: @@ -19,8 +19,8 @@ esdhc@70004000 { compatible = "fsl,imx51-esdhc"; reg = <0x70004000 0x4000>; interrupts = <1>; - fsl,cd-internal; - fsl,wp-internal; + fsl,cd-controller; + fsl,wp-controller; }; esdhc@70008000 { diff --git a/Documentation/watchdog/src/watchdog-test.c b/Documentation/watchdog/src/watchdog-test.c index 73ff5cc93e05..3da822967ee0 100644 --- a/Documentation/watchdog/src/watchdog-test.c +++ b/Documentation/watchdog/src/watchdog-test.c @@ -31,7 +31,7 @@ static void keep_alive(void) * or "-e" to enable the card. */ -void term(int sig) +static void term(int sig) { close(fd); fprintf(stderr, "Stopping watchdog ticks...\n"); |
