From: Tejun Heo <tj@kernel.org>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Thomas Gleixner <tglx@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/8] mm: Add ptep_try_install() for lockless empty-slot installs
Date: Mon, 18 May 2026 09:53:34 -1000 [thread overview]
Message-ID: <agtuPrgIDNKSu2Oo@slm.duckdns.org> (raw)
In-Reply-To: <9ba50fd2-077e-4291-9276-9adb18186873@kernel.org>
Hello,
On Mon, May 18, 2026 at 10:06:29AM +0200, David Hildenbrand (Arm) wrote:
> On 5/17/26 23:12, Tejun Heo wrote:
> > +static inline bool ptep_try_install(pte_t *ptep, pte_t new_pte)
> > +{
> > + return false;
> > +}
> > +#endif
>
> Ehm, what?
>
> This is a very, very, very bad generic idea/interface.
>
> On which ptes is this supposed to be used? User ptes or kernel ptes?
>
> Surely we don't want this on user ptes.
Yeah, this is only for the BPF arena PTEs which are already managed in their
own way. I'd be happy to place / gate it however appropriate.
Thanks.
--
tejun
next prev parent reply other threads:[~2026-05-18 19:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-17 21:12 [PATCHSET v2 sched_ext/for-7.2] bpf/arena: Direct kernel-side access Tejun Heo
2026-05-17 21:12 ` [PATCH 1/8] mm: Add ptep_try_install() for lockless empty-slot installs Tejun Heo
2026-05-18 8:06 ` David Hildenbrand (Arm)
2026-05-18 19:53 ` Tejun Heo [this message]
2026-05-19 8:00 ` David Hildenbrand (Arm)
2026-05-19 8:58 ` Tejun Heo
2026-05-19 9:05 ` David Hildenbrand (Arm)
2026-05-19 9:40 ` David Hildenbrand (Arm)
2026-05-17 21:12 ` [PATCH 2/8] bpf: Recover arena kernel faults with scratch page Tejun Heo
2026-05-17 21:12 ` [PATCH 3/8] bpf: Add sleepable variant of bpf_arena_alloc_pages for kernel callers Tejun Heo
2026-05-17 21:12 ` [PATCH 4/8] bpf: Add bpf_struct_ops_for_each_prog() Tejun Heo
2026-05-17 21:12 ` [PATCH 5/8] bpf/arena: Add bpf_arena_map_kern_vm_start() and bpf_prog_arena() Tejun Heo
2026-05-17 21:12 ` [PATCH 6/8] sched_ext: Require an arena for cid-form schedulers Tejun Heo
2026-05-17 21:12 ` [PATCH 7/8] sched_ext: Sub-allocator over kernel-claimed BPF arena pages Tejun Heo
2026-05-18 7:20 ` Peter Zijlstra
2026-05-18 19:51 ` Tejun Heo
2026-05-18 23:26 ` Alexei Starovoitov
2026-05-17 21:12 ` [PATCH 8/8] sched_ext: Convert ops.set_cmask() to arena-resident cmask Tejun Heo
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