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Save a multiplication in dl_task_fits_capacity() by using already maintained per-sched_dl_entity (i.e. per-task) `dl_runtime/dl_deadline` (dl_density). cap_scale(dl_deadline, cap) >= dl_runtime dl_deadline * cap >> SCHED_CAPACITY_SHIFT >= dl_runtime cap >= dl_runtime << SCHED_CAPACITY_SHIFT / dl_deadline cap >= (dl_runtime << BW_SHIFT / dl_deadline) >> BW_SHIFT - SCHED_CAPACITY_SHIFT cap >= dl_density >> BW_SHIFT - SCHED_CAPACITY_SHIFT __sched_setscheduler()->__checkparam_dl() ensures that the 2 corner cases (if conditions) `runtime == RUNTIME_INF (-1)` and `period == 0` of to_ratio(deadline, runtime) are not met when setting dl_density in __sched_setscheduler()-> __setscheduler_params()->__setparam_dl(). Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20220729111305.1275158-4-dietmar.eggemann@arm.com
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.