From: Tejun Heo <tj@kernel.org>
To: Andrea Righi <arighi@nvidia.com>
Cc: David Vernet <void@manifault.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>,
Peter Zijlstra <peterz@infradead.org>,
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>,
David Hildenbrand <david@kernel.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 7/8] sched_ext: Sub-allocator over kernel-claimed BPF arena pages
Date: Thu, 21 May 2026 07:22:29 -1000 [thread overview]
Message-ID: <0ea50f62b8255cc0ff1a96206096746a@kernel.org> (raw)
In-Reply-To: <ag66lfvACAEAI9w8@gpd4>
Hello,
On Thu, May 21, 2026 at 09:56:05AM +0200, Andrea Righi wrote:
> IIUC, since @page_cnt is sized to cover @size and the new chunk is added empty
> to the pool, gen_pool_alloc() here should always succeed. Should we do:
>
> if (WARN_ON_ONCE(!kern_va))
> return NULL;
>
> to catch potential logical bugs / future concurrency / exotic configurations?
Good point. It works for a single caller, but a concurrent one could drain
the new chunk between grow and retry. I'll switch it to a loop.
Thanks.
--
tejun
next prev parent reply other threads:[~2026-05-21 17:22 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-20 23:50 [PATCHSET v3 sched_ext/for-7.2] bpf/arena: Direct kernel-side access Tejun Heo
2026-05-20 23:50 ` [PATCH 1/8] mm: Add ptep_try_set() for lockless empty-slot installs Tejun Heo
2026-05-21 7:00 ` Andrea Righi
2026-05-21 17:37 ` [PATCH v3 " Tejun Heo
2026-05-20 23:50 ` [PATCH 2/8] bpf: Recover arena kernel faults with scratch page Tejun Heo
2026-05-21 3:16 ` Emil Tsalapatis
2026-05-21 9:42 ` Alexei Starovoitov
2026-05-21 17:39 ` Tejun Heo
2026-05-20 23:50 ` [PATCH 3/8] bpf: Add sleepable variant of bpf_arena_alloc_pages for kernel callers Tejun Heo
2026-05-21 3:17 ` Emil Tsalapatis
2026-05-20 23:50 ` [PATCH 4/8] bpf: Add bpf_struct_ops_for_each_prog() Tejun Heo
2026-05-21 4:07 ` Emil Tsalapatis
2026-05-20 23:50 ` [PATCH 5/8] bpf/arena: Add bpf_arena_map_kern_vm_start() and bpf_prog_arena() Tejun Heo
2026-05-21 4:08 ` Emil Tsalapatis
2026-05-20 23:50 ` [PATCH 6/8] sched_ext: Require an arena for cid-form schedulers Tejun Heo
2026-05-21 4:15 ` Emil Tsalapatis
2026-05-20 23:50 ` [PATCH 7/8] sched_ext: Sub-allocator over kernel-claimed BPF arena pages Tejun Heo
2026-05-21 7:56 ` Andrea Righi
2026-05-21 17:22 ` Tejun Heo [this message]
2026-05-21 17:37 ` [PATCH v2 " Tejun Heo
2026-05-21 17:54 ` Andrea Righi
2026-05-20 23:50 ` [PATCH 8/8] sched_ext: Convert ops.set_cmask() to arena-resident cmask Tejun Heo
2026-05-21 4:19 ` Emil Tsalapatis
-- strict thread matches above, loose matches on Subject: below --
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 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
2026-05-20 23:47 ` Tejun Heo
2026-05-21 7:27 ` Peter Zijlstra
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