linux-kernel - [PATCH v3 0/5] GRUB reclaiming fixes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230515025716.316888-1-vineeth@bitbyteword.org>
Date:   Sun, 14 May 2023 22:57:11 -0400
From:   Vineeth Pillai <vineeth@...byteword.org>
To:     luca.abeni@...tannapisa.it, Juri Lelli <juri.lelli@...hat.com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Valentin Schneider <vschneid@...hat.com>
Cc:     Vineeth Pillai <vineeth@...byteword.org>,
        Jonathan Corbet <corbet@....net>, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org
Subject: [PATCH v3 0/5] GRUB reclaiming fixes

Current reclaim calculation for GRUB is a bit inaccurate and the
inaccuracy gets larger as the bandwidth of tasks becomes smaller.

There are couple of issues with the existing implementation:
 - Loss of precision in division due to rounding off.
 - Minor bug in the reclaim calculation.
 - In SMP, tasks with smaller reservation tend to reclaim less
   even if its the only task on a cpu.
 - Inaccuracy when normal deadline tasks and SCHED_FLAG_RECLAIM
   tasks share the cpu.

This patch series aims to fix the above mentioned issues.

Changes in v3
-------------
1. Split the fixes into multiple self contained patches
2. Cover letter.

Vineeth Pillai (5):
  sched/deadline: Fix bandwidth reclaim equation in GRUB
  sched/deadline: Fix reclaim inaccuracy with SMP
  sched/deadline: Remove unused variable extra_bw
  sched/deadline: Account for normal deadline tasks in GRUB
  Documentation: sched/deadline: Update GRUB description

 Documentation/scheduler/sched-deadline.rst |  28 ++--
 kernel/sched/deadline.c                    | 160 ++++++++++-----------
 kernel/sched/sched.h                       |  18 ++-
 3 files changed, 112 insertions(+), 94 deletions(-)

-- 
2.40.1