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Date: Fri, 22 Aug 2025 12:57:20 -0700
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Subject: Re: [PATCH v1 13/14] sched: psi: implement bpf_psi_create_trigger()
 kfunc
To: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>, linux-mm@kvack.org,
 bpf@vger.kernel.org, Suren Baghdasaryan <surenb@google.com>,
 Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@suse.com>,
 David Rientjes <rientjes@google.com>,
 Matt Bobrowski <mattbobrowski@google.com>, Song Liu <song@kernel.org>,
 Kumar Kartikeya Dwivedi <memxor@gmail.com>,
 Alexei Starovoitov <ast@kernel.org>,
 Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
References: <20250818170136.209169-1-roman.gushchin@linux.dev>
 <20250818170136.209169-14-roman.gushchin@linux.dev>
 <CAEf4BzaSLWB1xpCjX35oxg2ySvvgRvEmQ01PtXv+xEz-Zkz07w@mail.gmail.com>
 <87ect5lde2.fsf@linux.dev>
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From: Martin KaFai Lau <martin.lau@linux.dev>
In-Reply-To: <87ect5lde2.fsf@linux.dev>
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On 8/20/25 5:36 PM, Roman Gushchin wrote:
> It will. Idk how big of a problem it is, given that the caller needs
> a trusted reference to bpf_psi. Also, is there a simple way to constrain
> it? Wdyt?

The bpf qdisc has the kfunc filtering. Take a look at the bpf_qdisc_kfunc_filter 
in bpf_qdisc.c.