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From: Marcelo Tosatti <mtosatti@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Chris Friesen <chris.friesen@windriver.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jim Somerville <Jim.Somerville@windriver.com>,
	Christoph Lameter <cl@linux.com>
Subject: [patch 0/3] affine kernel threads to specified cpumask (v3)
Date: Sat, 28 Mar 2020 12:21:17 -0300	[thread overview]
Message-ID: <20200328152117.881555226@redhat.com> (raw)

This is a kernel enhancement to configure the cpu affinity of kernel
threads via kernel boot option isolcpus=no_kthreads,<isolcpus_params>,<cpulist>

When this option is specified, the cpumask is immediately applied upon
thread launch. This does not affect kernel threads that specify cpu
and node.

This allows CPU isolation (that is not allowing certain threads
to execute on certain CPUs) without using the isolcpus=domain parameter,
making it possible to enable load balancing on such CPUs
during runtime.

Note-1: this is based off on Wind River's patch at
https://github.com/starlingx-staging/stx-integ/blob/master/kernel/kernel-std/centos/patches/affine-compute-kernel-threads.patch

Difference being that this patch is limited to modifying
kernel thread cpumask: Behaviour of other threads can
be controlled via cgroups or sched_setaffinity.

Note-2: Wind River's patch was based off Christoph Lameter's patch at
https://lwn.net/Articles/565932/ with the only difference being
the kernel parameter changed from kthread to kthread_cpus.

Changelog:

v2: use isolcpus= subcommand (Thomas Gleixner)

v3: s/MontaVista/Wind River/ on changelog (Chris Friesen)
    documentation updates		  (Chris Friesen)
    undeprecate isolcpus		  (Chris Friesen)
    general cleanups			  (Frederic Weisbecker)
    separate cpu_possible_mask kthread    
    mask change				  (Frederic Weisbecker)



             reply	other threads:[~2020-03-28 15:28 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-28 15:21 Marcelo Tosatti [this message]
2020-03-28 15:21 ` [patch 1/3] kthread: switch to cpu_possible_mask Marcelo Tosatti
2020-03-28 15:21 ` [patch 2/3] isolcpus: affine kernel threads to specified cpumask Marcelo Tosatti
2020-03-31  0:57   ` Frederic Weisbecker
2020-03-31 11:50     ` Marcelo Tosatti
2020-03-31 13:36       ` Frederic Weisbecker
2020-03-28 15:21 ` [patch 3/3] isolcpus: undeprecate on documentation Marcelo Tosatti
2020-03-31 15:22   ` Peter Zijlstra
2020-03-31 15:41     ` Marcelo Tosatti
2020-03-31 15:57       ` Peter Zijlstra
2020-04-04 23:05         ` Christopher Lameter
2020-03-31 15:43     ` Frederic Weisbecker

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