From: Hillf Danton <hdanton@sina.com>
To: Benjamin Segall <bsegall@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] locking/percpu-rwsem: do not do lock handoff in percpu_up_write
Date: Tue, 30 Jan 2024 19:41:56 +0800 [thread overview]
Message-ID: <20240130114156.1442-1-hdanton@sina.com> (raw)
In-Reply-To: <xm26o7d33mij.fsf@google.com>
On Mon, 29 Jan 2024 12:36:20 -0800 Benjamin Segall <bsegall@google.com>
>
> The basic locking issue was due to userspace rapidly spawning threads
> (or processes) more rapidly than the cpus they are running on can
> support, and this causing issues for unrelated threads doing cgroup
> operations on other cpus.
>
> The contention can be due to a combination of just straight up spawning
> way too many, userspace misconfiguration of cpus allowed, or load
> balancer weaknesses. (If you pick minimum cpu.shares values and have
> large machines, SCHED_LOAD_RESOLUTION isn't really enough for load
> balance to do a good job, and what you're telling the load balancer you
> want isn't really a good idea in the first place).
Sigh, add change to percpu-rwsem's handoff because cgroup has a cough
in chest.
prev parent reply other threads:[~2024-01-30 11:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-22 22:59 Benjamin Segall
2024-01-23 15:05 ` Hillf Danton
2024-01-24 22:10 ` Benjamin Segall
2024-01-25 11:04 ` Hillf Danton
2024-01-25 21:08 ` Benjamin Segall
2024-01-26 12:22 ` Hillf Danton
2024-01-26 20:40 ` Benjamin Segall
2024-01-27 11:20 ` Hillf Danton
2024-01-29 20:36 ` Benjamin Segall
2024-01-30 11:41 ` Hillf Danton [this message]
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