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Filename Latest commit message Latest commit date
Qais Yousef aae14aed37 sched/eas: Don't update misfit status if the task is pinned
[ Upstream commit 0ae78eec8aa64e645866e75005162603a77a0f49 ]

If the task is pinned to a cpu, setting the misfit status means that
we'll unnecessarily continuously attempt to migrate the task but fail.

This continuous failure will cause the balance_interval to increase to
a high value, and eventually cause unnecessary significant delays in
balancing the system when real imbalance happens.

Caught while testing uclamp where rt-app calibration loop was pinned to
cpu 0, shortly after which we spawn another task with high util_clamp
value. The task was failing to migrate after over 40ms of runtime due to
balance_interval unnecessary expanded to a very high value from the
calibration loop.

Not done here, but it could be useful to extend the check for pinning to
verify that the affinity of the task has a cpu that fits. We could end
up in a similar situation otherwise.

Fixes: 3b1baa6496 ("sched/fair: Add 'group_misfit_task' load-balance type")
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Acked-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210119120755.2425264-1-qais.yousef@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-04 10:26:23 +01:00
arch MIPS: properly stop .eh_frame generation 2021-03-04 10:26:21 +01:00
block bsg: free the request before return error code 2021-03-04 10:26:22 +01:00
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drivers media: uvcvideo: Accept invalid bFormatIndex and bFrameIndex values 2021-03-04 10:26:23 +01:00
fs
include tcp: fix SO_RCVLOWAT related hangs under mem pressure 2021-03-04 10:26:17 +01:00
init
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kernel sched/eas: Don't update misfit status if the task is pinned 2021-03-04 10:26:23 +01:00
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net bpf: Fix bpf_fib_lookup helper MTU check for SKB ctx 2021-03-04 10:26:17 +01:00
samples
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security evm: Fix memleak in init_desc 2021-03-04 10:26:21 +01:00
sound ASoC: cs42l56: fix up error handling in probe 2021-03-04 10:26:21 +01:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.