From: Tejun Heo <tj@kernel.org>
To: Tao Cui <cui.tao@linux.dev>
Cc: Tao Cui <cuitao@kylinos.cn>,
void@manifault.com, arighi@nvidia.com, changwoo@igalia.com,
suzhidao@xiaomi.com, yphbchou0911@gmail.com,
zhaomengmeng@kylinos.cn, sched-ext@lists.linux.dev,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH] sched_ext/scx_flatcg: expire cached hweights on weight changes
Date: Fri, 14 Aug 2026 10:56:19 -1000 [thread overview]
Message-ID: <003d0a4f1c448113e18f9f5d61d00e99@kernel.org> (raw)
In-Reply-To: <20260814144116.2767304-1-cui.tao@linux.dev>
On Fri, Aug 14, 2026 at 10:41:16PM +0800, Tao Cui wrote:
> fcg_cgroup_set_weight() updates cgc->weight and the parent's
> child_weight_sum but doesn't bump hweight_gen, so the hweights cached by
> cgrp_refresh_hweight() stay stale until some task activation bumps the
> generation. For cgroups whose tasks never go through a 0->n runnable
> transition (e.g. persistently busy ones), a cpu.weight change never
> propagates to scheduling at all.
Applied to sched_ext/for-7.3.
Thanks.
--
tejun
prev parent reply other threads:[~2026-08-14 20:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-14 14:41 [PATCH] sched_ext/scx_flatcg: expire cached hweights on weight changes Tao Cui
2026-08-14 14:48 ` Tao Cui
2026-08-14 22:23 ` Tejun Heo
2026-08-14 17:20 ` bot+bpf-ci
2026-08-14 20:56 ` Tejun Heo [this message]
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