From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 BAE643A7839 for ; Thu, 30 Jul 2026 20:35:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785443744; cv=none; b=SvFJA/lLd+priaIfcepDIEDXQp5S4xOsROMbdnLbIdqprvWs6s4BTE8PLO8KrGmlshGlxVPmicxkQukkyLvWD8GJpOOfgEZAOz2M4YkV/Woz0ZNaah0JLz32Cgm2ILdCpqV94pq2ZyqbU20sOVFxCJBoEMpAIqMcfYuZNqmR6iw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785443744; c=relaxed/simple; bh=zBCRRN2sWVo2r37jQBk4RKlk+khTg2FJPpvVcXxrxcA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jIV/apn9sMKf1xhsTPDz8M7w0Gc8trX6MpG4YbTcfgYrVuiiHkNrCsG60EFSs5Jq/MXWMRpYhijA4xaE+OhTiYDqLIkZQ/Bd5U+/FaYQHiqyFJmapAWR2bhChtxMhlRU6YuaAoMC1AvegYT4f1Etj3Yy7ypatHzJi0nZS0XtUr4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=EXUba4QT; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EXUba4QT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1785443738; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zBCRRN2sWVo2r37jQBk4RKlk+khTg2FJPpvVcXxrxcA=; b=EXUba4QT/SAsnJg8hEZPs2e/mG+L0sURGczDxfSA1xAw+Q4iW6Si8shQGSei88LWCUfDjT CFpTUcvF1aJO2QpxPv8YsZbhpS6x8V7xpWO6lyZdjd2k+6n+4WRC34qztDAJIood0USuEV twhQflXOzwKV3XmElVNs7pMhswX1DSc= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-590-Z4Mu8WJZPSqgt6YfMC9tYg-1; Thu, 30 Jul 2026 16:35:32 -0400 X-MC-Unique: Z4Mu8WJZPSqgt6YfMC9tYg-1 X-Mimecast-MFC-AGG-ID: Z4Mu8WJZPSqgt6YfMC9tYg_1785443729 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6D75719560B6; Thu, 30 Jul 2026 20:35:29 +0000 (UTC) Received: from fedora (unknown [10.44.33.21]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 0584B1956089; Thu, 30 Jul 2026 20:35:24 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 30 Jul 2026 22:35:29 +0200 (CEST) Date: Thu, 30 Jul 2026 22:35:23 +0200 From: Oleg Nesterov To: Mateusz Guzik Cc: Breno Leitao , Christian Brauner , Jens Axboe , Pavel Begunkov , Alexander Viro , Jan Kara , Alexey Gladkov , Linus Torvalds , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org Subject: Re: [PATCH v3 1/1] pipe: only enable the extra wake_up(rd_wait) for edge-triggered consumers Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Mateusz, Breno, thanks, I'll try to think about it later, but... On 07/30, Mateusz Guzik wrote: > > On Thu, Jul 30, 2026 at 4:38 PM Oleg Nesterov wrote: > > What exactly do you think the comment should say? I agree with anything in > > advance. I thought that "edge-triggered" provides enough info, but I would > > be happy to improve the docs. > > > > how about: There is userspace depending on the extra wake up, see > commit 3a34b13a88caeb28 ("pipe: make pipe writes always wake up > readers") for details. To me this looks confusing. IMO, the comment like this (with the reference to the commit) would make sense to document the unconditional/undocumented kill_fasync(fasync_readers) in anon_pipe_write(), this SIGIO is even worse in some sense and I would like to discuss it another time ;) But as for poll_usage/poll_et... We have the established API, and (afaics) it works as documented. It doesn't matter if EPOLLET behaviour is good or bad. We only need to document what ->poll_et means for pipes. > > And the helper's name? pipe_enable_poll_et() ? > > perhaps pipe_enable_epoll_semantics()? Again, contrary to the current comments this is not Epoll-only... Oleg.