From nobody Sun Feb 8 20:29:19 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72D7C143C6F for ; Tue, 12 Mar 2024 22:20:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710282016; cv=none; b=q9PQmpkGA8F0Fdhcl+MJR/FR7jI8LdwJYqoLF/Rke5wWU94Z/mZRzMlF5FZJsC8eAyxhseuZtz+HwkskW4v0hZfX9BeTx7K4LfsaK5MRmIqns6s8g5Dd+litRwe+KWDPPoEx0rccAYheIsVLVH8jetkX6Uil7ASAnBdyn0w3zQU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710282016; c=relaxed/simple; bh=Fn4AJ/vrIiVdY+JUXJRLI5EIHGywgJFTV5iUg9TbdC8=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=nOD9TZ0dLHPtPBnL7/hYw96LZb72A9k4FLket3SjBzJn+UIPkQ7fCd8e68vb41IKHzEXdXhwSMBoRBsCszA4WHYpw/K74sHf9qloCpr04dkrqFQqa8yEShzQQuJER9+mQ54p4pZXo3S3pSs5ijIriWpq52WSg0tXNFUBx31olXg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29DD6C43399; Tue, 12 Mar 2024 22:20:16 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rkAVr-000000022L0-2etg; Tue, 12 Mar 2024 18:22:23 -0400 Message-ID: <20240312222223.494701270@goodmis.org> User-Agent: quilt/0.67 Date: Tue, 12 Mar 2024 18:21:02 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [for-linus][PATCH 3/5] ring-buffer: Reuse rb_watermark_hit() for the poll logic References: <20240312222059.823191689@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Steven Rostedt (Google)" The check for knowing if the poll should wait or not is basically the exact same logic as rb_watermark_hit(). The only difference is that rb_watermark_hit() also handles the !full case. But for the full case, the logic is the same. Just call that instead of duplicating the code in ring_buffer_poll_wait(). Link: https://lore.kernel.org/linux-trace-kernel/20240312131952.802267543@g= oodmis.org Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 99fdda29ce4e..8c3730a88662 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -960,25 +960,18 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *b= uffer, int cpu, } =20 if (full) { - unsigned long flags; - poll_wait(filp, &rbwork->full_waiters, poll_table); =20 - raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); - if (!cpu_buffer->shortest_full || - cpu_buffer->shortest_full > full) - cpu_buffer->shortest_full =3D full; - raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); - if (full_hit(buffer, cpu, full)) + if (rb_watermark_hit(buffer, cpu, full)) return EPOLLIN | EPOLLRDNORM; /* * Only allow full_waiters_pending update to be seen after - * the shortest_full is set. If the writer sees the - * full_waiters_pending flag set, it will compare the - * amount in the ring buffer to shortest_full. If the amount - * in the ring buffer is greater than the shortest_full - * percent, it will call the irq_work handler to wake up - * this list. The irq_handler will reset shortest_full + * the shortest_full is set (in rb_watermark_hit). If the + * writer sees the full_waiters_pending flag set, it will + * compare the amount in the ring buffer to shortest_full. + * If the amount in the ring buffer is greater than the + * shortest_full percent, it will call the irq_work handler + * to wake up this list. The irq_handler will reset shortest_full * back to zero. That's done under the reader_lock, but * the below smp_mb() makes sure that the update to * full_waiters_pending doesn't leak up into the above. --=20 2.43.0