From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 888FDC04A68 for ; Thu, 28 Jul 2022 08:23:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234619AbiG1IXM (ORCPT ); Thu, 28 Jul 2022 04:23:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234381AbiG1IXL (ORCPT ); Thu, 28 Jul 2022 04:23:11 -0400 Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BD7161DBA; Thu, 28 Jul 2022 01:23:10 -0700 (PDT) Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 0FE8A1C0003; Thu, 28 Jul 2022 10:23:08 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ucw.cz; s=gen1; t=1658996588; 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: in-reply-to:in-reply-to:references:references; bh=EXfM02GFzA8ELpnDKlyOIJmK9T5oL5LwlIPHTBNZ798=; b=X6lgA01XcFzrlnlOIHT7Y0KehfX6lFvZeL7ylIjA/9bAsKdg5i/1rt3bd3VPh9Uwmk5JT0 PtI11zG4C2DfgHZQWByy4HJEgtgldNTlTCprskJeeuSAfQpLj3LnkrGX8ArxhY355m6mAw 0JEA3Eni199N5DLQxMiVLxpPJq6zbUM= Date: Thu, 28 Jul 2022 10:23:07 +0200 From: Pavel Machek To: Ming Lei Cc: Damien Le Moal , Gabriel Krisman Bertazi , lsf-pc@lists.linux-foundation.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] block drivers in user space Message-ID: <20220728082307.GA15112@duo.ucw.cz> References: <3702afe7-2918-42e7-110b-efa75c0b58e8@opensource.wdc.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7JfCtLOvnd9MIVvH" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org --7JfCtLOvnd9MIVvH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > > If you have actual report, I am happy to take account into it, otherw= ise not > > > sure if it is worth of time/effort in thinking/addressing one pure th= eoretical > > > concern. > >=20 > > Hi Ming, > >=20 > > Thanks for your look & reply. > >=20 > > That is not a wild guess. That is a basic difference between > > in-kernel native block-based drivers and user-space block drivers. >=20 > Please look at my comment, wrt. your pure theoretical concern, userspace > block driver is same with kernel loop/nbd. >=20 > Did you see such report on loop & nbd? Can you answer my questions wrt. > kernel thread B? Yes, nbd is known to deadlock under high loads. Don't do that. Pavel --=20 People of Russia, stop Putin before his war on Ukraine escalates. --7JfCtLOvnd9MIVvH Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCYuJHawAKCRAw5/Bqldv6 8gEoAJ9zmwt5woMTM0cAO4S+OR5Z1j5hgQCgmiyqaOqsiNQinTaL5FiPFvKgf78= =GB7n -----END PGP SIGNATURE----- --7JfCtLOvnd9MIVvH--