1. 26 Apr, 2018 1 commit
    • Tejun Heo's avatar
      cgroup: Rename kernel/cgroup/stat.c to kernel/cgroup/rstat.c · a5c2b93f
      Tejun Heo authored
      stat is too generic a name and ends up causing subtle confusions.
      It'll be made generic so that controllers can plug into it, which will
      make the problem worse.  Let's rename it to something more specific -
      cgroup_rstat for cgroup recursive stat.
      First, rename kernel/cgroup/stat.c to kernel/cgroup/rstat.c.  No
      content changes.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
  2. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      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 <5
      All documentation files were explicitly excluded.
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
         For non */uapi/* files that summary was:
         SPDX license identifier                            # files
         GPL-2.0                                              11139
         and resulted in the first patch in this series.
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
         SPDX license identifier                            # files
         GPL-2.0 WITH Linux-syscall-note                        930
         and resulted in the second patch in this series.
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
         SPDX license identifier                            # files
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
         and that resulted in the third patch in this series.
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
  3. 25 Sep, 2017 1 commit
    • Tejun Heo's avatar
      cgroup: Implement cgroup2 basic CPU usage accounting · 041cd640
      Tejun Heo authored
      In cgroup1, while cpuacct isn't actually controlling any resources, it
      is a separate controller due to combination of two factors -
      1. enabling cpu controller has significant side effects, and 2. we
      have to pick one of the hierarchies to account CPU usages on.  cpuacct
      controller is effectively used to designate a hierarchy to track CPU
      usages on.
      cgroup2's unified hierarchy removes the second reason and we can
      account basic CPU usages by default.  While we can use cpuacct for
      this purpose, both its interface and implementation leave a lot to be
      desired - it collects and exposes two sources of truth which don't
      agree with each other and some of the exposed statistics don't make
      much sense.  Also, it propagates all the way up the hierarchy on each
      accounting event which is unnecessary.
      This patch adds basic resource accounting mechanism to cgroup2's
      unified hierarchy and accounts CPU usages using it.
      * All accountings are done per-cpu and don't propagate immediately.
        It just bumps the per-cgroup per-cpu counters and links to the
        parent's updated list if not already on it.
      * On a read, the per-cpu counters are collected into the global ones
        and then propagated upwards.  Only the per-cpu counters which have
        changed since the last read are propagated.
      * CPU usage stats are collected and shown in "cgroup.stat" with "cpu."
        prefix.  Total usage is collected from scheduling events.  User/sys
        breakdown is sourced from tick sampling and adjusted to the usage
        using cputime_adjust().
      This keeps the accounting side hot path O(1) and per-cpu and the read
      side O(nr_updated_since_last_read).
      v2: Minor changes and documentation updates as suggested by Waiman and
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Li Zefan <lizefan@huawei.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Waiman Long <longman@redhat.com>
      Cc: Roman Gushchin <guro@fb.com>
  4. 14 Jun, 2017 1 commit
  5. 10 Jan, 2017 1 commit
    • Parav Pandit's avatar
      rdmacg: Added rdma cgroup controller · 39d3e758
      Parav Pandit authored
      Added rdma cgroup controller that does accounting, limit enforcement
      on rdma/IB resources.
      Added rdma cgroup header file which defines its APIs to perform
      charging/uncharging functionality. It also defined APIs for RDMA/IB
      stack for device registration. Devices which are registered will
      participate in controller functions of accounting and limit
      enforcements. It define rdmacg_device structure to bind IB stack
      and RDMA cgroup controller.
      RDMA resources are tracked using resource pool. Resource pool is per
      device, per cgroup entity which allows setting up accounting limits
      on per device basis.
      Currently resources are defined by the RDMA cgroup.
      Resource pool is created/destroyed dynamically whenever
      charging/uncharging occurs respectively and whenever user
      configuration is done. Its a tradeoff of memory vs little more code
      space that creates resource pool object whenever necessary, instead of
      creating them during cgroup creation and device registration time.
      Signed-off-by: default avatarParav Pandit <pandit.parav@gmail.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
  6. 27 Dec, 2016 3 commits