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Mon, 02 Nov 2026 17:47:23 -0800 (PST) Received: from localhost ([153.61.198.244]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2eb392965fesm33422135ad.59.2026.11.02.17.47.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 02 Nov 2026 17:47:22 -0800 (PST) Content-Type: text/plain; charset=UTF-8 Date: Tue, 03 Nov 2026 01:47:22 +0000 Message-Id: From: "Alexei Starovoitov" To: "Kumar Kartikeya Dwivedi" Cc: "Emil Tsalapatis" , , , , , "Tejun Heo" Subject: Re: [PATCH bpf 1/2] bpf: recover page faults across all arenas In-Reply-To: References: <20261028015141.10710-1-emil@etsalapatis.com> <20261028015141.10710-2-emil@etsalapatis.com> Content-Transfer-Encoding: 8bit X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 On Mon, Nov 02, 2026 at 03:35 PM Kumar Kartikeya Dwivedi wrote: >> > - prog = bpf_prog_find_from_stack(); >> >> This has to stay. If there are thousands arena. Above should still be a fast path. >> Only for sched-ext arena access it should search link link. > > We cannot rely on this, there might be a different program in the call > stack. That's why there is an equality check on the arena when > actually reporting, to make sure it's going to the right program. I meant it as a fast path, not as the only path. the equality check is needed, of course. A different prog on the stack will fail that check and the handler will do latch search.