linux-kernel - [RFC PATCH 0/1] sched/isolation: Warn when maxcpus= is specified with nohz

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>] [day] [month] [year] [list]

Message-ID: <b51c2515-8cbc-ac7e-97ea-c6fd0e07cad6@atomlin.com>
Date: Sun, 1 Dec 2024 18:42:44 +0000 (GMT)
From: Aaron Tomlin <atomlin@...mlin.com>
To: oleg@...hat.com, frederic@...nel.org, peterz@...radead.org
cc: atomlin@...mlin.com, nick.lange@...il.com, seun.ewulomi@...il.com, 
    linux-kernel@...r.kernel.org
Subject: [RFC PATCH 0/1] sched/isolation: Warn when maxcpus= is specified
 with nohz_full= or isolcpus=

Hi Oleg, Frederic, Peter,

I have seen a case where maxcpus=1 and e.g. nohz_full=1,3-31, was used to
force the CPU affinity of certain unbound or non CPU-specific kernel
threads at boot-time. Albeit, since commit 9cc5b8656892a ("isolcpus: Affine
unbound kernel threads to housekeeping cpus") this is handled entirely via
nohz_full=. I thought it might be worth adding a warning.

Aaron Tomlin (1):
  sched/isolation: Warn when maxcpus= is specified with nohz_full= or
    isolcpus=

 kernel/sched/isolation.c | 2 ++
 1 file changed, 2 insertions(+)

--
2.47.1

-- 
Aaron Tomlin
View attachment "0001-sched-isolation-Warn-when-maxcpus-is-specified-with-.patch" of type "text/plain" (1966 bytes)