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Thu, 24 Sep 2026 14:11:48 -0700 (PDT) Content-Type: text/plain; charset=UTF-8 Date: Thu, 24 Sep 2026 21:11:47 +0000 Message-Id: To: "Kumar Kartikeya Dwivedi" , Cc: "Andrii Nakryiko" , "Daniel Borkmann" , "Eduard Zingerman" , "Emil Tsalapatis" , "Tejun Heo" , , Subject: Re: [PATCH bpf-next v2 2/5] bpf: Add file descriptor interface for program streams From: "Alexei Starovoitov" In-Reply-To: <20260924162641.1922423-3-memxor@gmail.com> References: <20260924162641.1922423-1-memxor@gmail.com> <20260924162641.1922423-3-memxor@gmail.com> X-Mailer: mkdraft (claude review draft; edit before sending) Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, Sep 24, 2026 at 06:26 PM Kumar Kartikeya Dwivedi wrote: > +static void bpf_stream_publish(struct bpf_stream *stream, int len) > +{ > + /* Pairs with atomic_read_acquire() in bpf_stream_readable_bytes(). */ > + (void)atomic_add_return_release(len, &stream->readable); > + bpf_stream_queue_notify(stream); > +} This queues irq_work on every bpf_stream_vprintk() and every stage commit, whether anyone opened the stream or not. That's an irq_work interrupt per print for every existing user. ringbuf queues it only when the consumer caught up. The result of atomic_add_return_release() is thrown away. can we queue the work only when it returns len, i.e. when the stream was empty ? pw-bot: cr