From: Qiliang Yuan <realwujing@gmail.com>
To: peterz@infradead.org
Cc: longman@redhat.com, cgroups@vger.kernel.org,
akpm@linux-foundation.org, anna-maria@linutronix.de,
boqun.feng@gmail.com, bsegall@google.com,
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urezki@gmail.com, vbabka@suse.cz, vincent.guittot@linaro.org,
vschneid@redhat.com, ziy@nvidia.com
Subject: Re: [PATCH 01/15] sched/isolation: Support dynamic allocation for housekeeping masks
Date: Mon, 30 Mar 2026 19:43:21 +0800 [thread overview]
Message-ID: <20260330114348.102265-1-realwujing@gmail.com> (raw)
In-Reply-To: <20260325135707.GZ3738786@noisy.programming.kicks-ass.net>
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Hi Peter,
On Wed, Mar 25, 2026 at 02:57:07PM +0100, Peter Zijlstra wrote:
> I think I asked this a while ago; why do we have more than one mask?
> What is the actual purpose of being able to separate RCU from Timers?
That's a fair point. For the vast majority of use cases (like NOHZ_FULL),
these masks are indeed identical and should be updated as a single unit.
The original motivation for separation was to allow extreme fine-tuning in
HFT environments—for example, offloading RCU callbacks to keep a core
mostly clean but allowing pinned timers for specific localized
telemetry/monitoring.
However, I acknowledge this adds significant complexity. In V13, I will
unify these into a single "Global Housekeeping Mask" by default to
simplify the configuration space, while keeping the underlying notifier
infrastructure flexible enough for future specialized needs.
next parent reply other threads:[~2026-03-30 11:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260325135707.GZ3738786@noisy.programming.kicks-ass.net>
2026-03-30 11:43 ` Qiliang Yuan [this message]
2026-03-31 9:23 ` [PATCH 01/15] sched/isolation: Support dynamic allocation for housekeeping masks Frederic Weisbecker
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