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android / kernel / common / ada4ab688a3055c7ceec8637e64c633cf7624456
commitada4ab688a3055c7ceec8637e64c633cf7624456[log] [tgz]
authorLi Li <dualli@google.com>Thu May 26 15:00:18 2022 -0700
committerLi Li <dualli@google.com>Fri Jul 08 10:57:27 2022 -0700
tree5f6921fef913122ebab8374724fe9089f61d4275
parentcc9d67ff745c7e47893a9724824882c1e7b25764 [diff]
FROMGIT: Binder: add TF_UPDATE_TXN to replace outdated txn

When the target process is busy, incoming oneway transactions are
queued in the async_todo list. If the clients continue sending extra
oneway transactions while the target process is frozen, this queue can
become too large to accommodate new transactions. That's why binder
driver introduced ONEWAY_SPAM_DETECTION to detect this situation. It's
helpful to debug the async binder buffer exhausting issue, but the
issue itself isn't solved directly.

In real cases applications are designed to send oneway transactions
repeatedly, delivering updated inforamtion to the target process.
Typical examples are Wi-Fi signal strength and some real time sensor
data. Even if the apps might only care about the lastet information,
all outdated oneway transactions are still accumulated there until the
frozen process is thawed later. For this kind of situations, there's
no existing method to skip those outdated transactions and deliver the
latest one only.

This patch introduces a new transaction flag TF_UPDATE_TXN. To use it,
use apps can set this new flag along with TF_ONE_WAY. When such an
oneway transaction is to be queued into the async_todo list of a frozen
process, binder driver will check if any previous pending transactions
can be superseded by comparing their code, flags and target node. If
such an outdated pending transaction is found, the latest transaction
will supersede that outdated one. This effectively prevents the async
binder buffer running out and saves unnecessary binder read workloads.

Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Li Li <dualli@google.com>
Link: https://lore.kernel.org/r/20220526220018.3334775-2-dualli@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 231624308
Test: manually check async binder buffer size of frozen apps
Test: stress test with kernel 4.14/4.19/5.10/5.15
(cherry picked from commit 9864bb4801331daa48514face9d0f4861e4d485b
 git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
  char-misc-next)
Change-Id: I1c4bff1eda1ca15aaaad5bf696c8fc00be743176
3 files changed
tree: 5f6921fef913122ebab8374724fe9089f61d4275
  1. android/
  2. arch/
  3. block/
  4. certs/
  5. crypto/
  6. Documentation/
  7. drivers/
  8. fs/
  9. include/
  10. init/
  11. ipc/
  12. kernel/
  13. lib/
  14. LICENSES/
  15. mm/
  16. net/
  17. samples/
  18. scripts/
  19. security/
  20. sound/
  21. tools/
  22. usr/
  23. virt/
  24. .clang-format
  25. .cocciconfig
  26. .get_maintainer.ignore
  27. .gitattributes
  28. .gitignore
  29. .mailmap
  30. build.config.aarch64
  31. build.config.allmodconfig
  32. build.config.allmodconfig.aarch64
  33. build.config.allmodconfig.arm
  34. build.config.allmodconfig.x86_64
  35. build.config.arm
  36. build.config.common
  37. build.config.db845c
  38. build.config.gki
  39. build.config.gki-debug.aarch64
  40. build.config.gki-debug.x86_64
  41. build.config.gki.aarch64
  42. build.config.gki.x86_64
  43. build.config.gki_kasan
  44. build.config.gki_kasan.aarch64
  45. build.config.gki_kasan.x86_64
  46. build.config.gki_kprobes
  47. build.config.gki_kprobes.aarch64
  48. build.config.gki_kprobes.x86_64
  49. build.config.hikey960
  50. build.config.x86_64
  51. COPYING
  52. CREDITS
  53. Kbuild
  54. Kconfig
  55. MAINTAINERS
  56. Makefile
  57. OWNERS
  58. README
  59. README.md
README.md

How do I submit patches to Android Common Kernels

  1. BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.

  2. LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.

Common Kernel patch requirements

  • All patches must conform to the Linux kernel coding standards and pass script/checkpatch.pl
  • Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
  • If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch: UPSTREAM:, BACKPORT:, FROMGIT:, FROMLIST:, or ANDROID:.
  • All patches must have a Change-Id: tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html)
  • If an Android bug has been assigned, there must be a Bug: tag.
  • All patches must have a Signed-off-by: tag by the author and the submitter

Additional requirements are listed below based on patch type

Requirements for backports from mainline Linux: UPSTREAM:, BACKPORT:

  • If the patch is a cherry-pick from Linux mainline with no changes at all
    • tag the patch subject with UPSTREAM:.
    • add upstream commit information with a (cherry-picked from ...) line
    • Example:
      • if the upstream commit message is
        important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

    - then Joe Smith would upload the patch for the common kernel as

        UPSTREAM: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry-picked from c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch requires any changes from the upstream version, tag the patch with BACKPORT: instead of UPSTREAM:.
    • use the same tags as UPSTREAM:
    • add comments about the changes under the (cherry-picked from ...) line
    • Example:
        BACKPORT: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry-picked from c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        [ Resolved minor conflict in drivers/foo/bar.c ]
        Signed-off-by: Joe Smith <joe.smith@foo.org>

Requirements for other backports: FROMGIT:, FROMLIST:,

  • If the patch has been merged into an upstream maintainer tree, but has not yet been merged into Linux mainline
    • tag the patch subject with FROMGIT:
    • add info on where the patch came from as (cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't use linux-next for example).
    • if changes were required, use BACKPORT: FROMGIT:
    • Example:
      • if the commit message in the maintainer tree is
        important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

    - then Joe Smith would upload the patch for the common kernel as

        FROMGIT: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        (cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
         https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch has been submitted to LKML, but not accepted into any maintainer tree
    • tag the patch subject with FROMLIST:
    • add a Link: tag with a link to the submittal on lore.kernel.org
    • if changes were required, use BACKPORT: FROMLIST:
    • Example:
        FROMLIST: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>

Requirements for Android-specific patches: ANDROID:

  • If the patch is fixing a bug to Android-specific code
    • tag the patch subject with ANDROID:
    • add a Fixes: tag that cites the patch with the bug
    • Example:
        ANDROID: fix android-specific bug in foobar.c

        This is the detailed description of the important fix

        Fixes: 1234abcd2468 ("foobar: add cool feature")
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch is a new feature
    • tag the patch subject with ANDROID:
    • add a Bug: tag with the Android bug (required for android-specific features)