Eric Lee / smarc-fsl-linux-kernel

02 Nov, 2017

1 commit

  • b24413180   License cleanup: add SPDX GPL-2.0 license identifier to files with no license ... Browse Code »

    Many source files in the tree are missing licensing information, which
    makes it harder for compliance tools to determine the correct license.

    By default all files without license information are under the default
    license of the kernel, which is GPL version 2.

    Update the files which contain no license information with the 'GPL-2.0'
    SPDX license identifier. The SPDX identifier is a legally binding
    shorthand, which can be used instead of the full boiler plate text.

    This patch is based on work done by Thomas Gleixner and Kate Stewart and
    Philippe Ombredanne.

    How this work was done:

    Patches were generated and checked against linux-4.14-rc6 for a subset of
    the use cases:
    - file had no licensing information it it.
    - file was a */uapi/* one with no licensing information in it,
    - file was a */uapi/* one with existing licensing information,

    Further patches will be generated in subsequent months to fix up cases
    where non-standard license headers were used, and references to license
    had to be inferred by heuristics based on keywords.

    The analysis to determine which SPDX License Identifier to be applied to
    a file was done in a spreadsheet of side by side results from of the
    output of two independent scanners (ScanCode & Windriver) producing SPDX
    tag:value files created by Philippe Ombredanne. Philippe prepared the
    base worksheet, and did an initial spot review of a few 1000 files.

    The 4.13 kernel was the starting point of the analysis with 60,537 files
    assessed. Kate Stewart did a file by file comparison of the scanner
    results in the spreadsheet to determine which SPDX license identifier(s)
    to be applied to the file. She confirmed any determination that was not
    immediately clear with lawyers working with the Linux Foundation.

    Criteria used to select files for SPDX license identifier tagging was:
    - Files considered eligible had to be source code files.
    - Make and config files were included as candidates if they contained >5
    lines of source
    - File already had some variant of a license header in it (even if
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

19 Apr, 2017

1 commit

  • 8330cdb0f   block: Make writeback throttling defaults consistent for SQ devices ... Browse Code »

    When CFQ is used as an elevator, it disables writeback throttling
    because they don't play well together. Later when a different elevator
    is chosen for the device, writeback throttling doesn't get enabled
    again as it should. Make sure CFQ enables writeback throttling (if it
    should be enabled by default) when we switch from it to another IO
    scheduler.

    Signed-off-by: Jan Kara
    Signed-off-by: Jens Axboe

    Jan Kara
     

28 Mar, 2017

1 commit

  • 88eeca495   block: track request size in blk_issue_stat ... Browse Code »

    Currently there is no way to know the request size when the request is
    finished. Next patch will need this info. We could add extra field to
    record the size, but blk_issue_stat has enough space to record it, so
    this patch just overloads blk_issue_stat. With this, we will have 49bits
    to track time, which still is very long time.

    Signed-off-by: Shaohua Li
    Signed-off-by: Jens Axboe

    Shaohua Li
     

22 Mar, 2017

1 commit

  • 34dbad5d2   blk-stat: convert to callback-based statistics reporting ... Browse Code »

    Currently, statistics are gathered in ~0.13s windows, and users grab the
    statistics whenever they need them. This is not ideal for both in-tree
    users:

    1. Writeback throttling wants its own dynamically sized window of
    statistics. Since the blk-stats statistics are reset after every
    window and the wbt windows don't line up with the blk-stats windows,
    wbt doesn't see every I/O.
    2. Polling currently grabs the statistics on every I/O. Again, depending
    on how the window lines up, we may miss some I/Os. It's also
    unnecessary overhead to get the statistics on every I/O; the hybrid
    polling heuristic would be just as happy with the statistics from the
    previous full window.

    This reworks the blk-stats infrastructure to be callback-based: users
    register a callback that they want called at a given time with all of
    the statistics from the window during which the callback was active.
    Users can dynamically bucketize the statistics. wbt and polling both
    currently use read vs. write, but polling can be extended to further
    subdivide based on request size.

    The callbacks are kept on an RCU list, and each callback has percpu
    stats buffers. There will only be a few users, so the overhead on the
    I/O completion side is low. The stats flushing is also simplified
    considerably: since the timer function is responsible for clearing the
    statistics, we don't have to worry about stale statistics.

    wbt is a trivial conversion. After the conversion, the windowing problem
    mentioned above is fixed.

    For polling, we register an extra callback that caches the previous
    window's statistics in the struct request_queue for the hybrid polling
    heuristic to use.

    Since we no longer have a single stats buffer for the request queue,
    this also removes the sysfs and debugfs stats entries. To replace those,
    we add a debugfs entry for the poll statistics.

    Signed-off-by: Omar Sandoval
    Signed-off-by: Jens Axboe

    Omar Sandoval
     

29 Nov, 2016

3 commits

12 Nov, 2016

2 commits

11 Nov, 2016

1 commit

  • e34cbd307   blk-wbt: add general throttling mechanism ... Browse Code »

    We can hook this up to the block layer, to help throttle buffered
    writes.

    wbt registers a few trace points that can be used to track what is
    happening in the system:

    wbt_lat: 259:0: latency 2446318
    wbt_stat: 259:0: rmean=2446318, rmin=2446318, rmax=2446318, rsamples=1,
    wmean=518866, wmin=15522, wmax=5330353, wsamples=57
    wbt_step: 259:0: step down: step=1, window=72727272, background=8, normal=16, max=32

    This shows a sync issue event (wbt_lat) that exceeded it's time. wbt_stat
    dumps the current read/write stats for that window, and wbt_step shows a
    step down event where we now scale back writes. Each trace includes the
    device, 259:0 in this case.

    Signed-off-by: Jens Axboe

    Jens Axboe