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 X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,T_DKIMWL_WL_HIGH autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 79133C004E4 for ; Wed, 13 Jun 2018 07:37:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E4E9208B0 for ; Wed, 13 Jun 2018 07:37:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="162muyA+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E4E9208B0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934702AbeFMHg6 (ORCPT ); Wed, 13 Jun 2018 03:36:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:43248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933732AbeFMHg4 (ORCPT ); Wed, 13 Jun 2018 03:36:56 -0400 Received: from localhost (unknown [193.47.165.251]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A572420891; Wed, 13 Jun 2018 07:36:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528875416; bh=zapFHhH/HhsTDcYm8nhZBYDyLSxOqE2PGrKqpXwMkXQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=162muyA+yvaE5AeoDw2vzhEZu9TEI+VB5vZginIxH7OPGGFfDr52+sYPnu5avxmTC Oy65HrpCCeOxafXOQ/PAO+Vbhz92IdrV3UK41L56sY0O4nz9TEBwTKRs+1tZmqilN5 iGfplxKzzhwkbBlPquaIUvMqDoZIQPJ9a5g3WeKM= Date: Wed, 13 Jun 2018 10:36:53 +0300 From: Leon Romanovsky To: Matthew Wilcox Cc: Jason Gunthorpe , hans.westgaard.ry@oracle.com, Doug Ledford , Matthew Wilcox , linux-rdma@vger.kernel.org, =?iso-8859-1?Q?H=E5kon?= Bugge , Parav Pandit , Jack Morgenstein , Pravin Shedge , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] IB/mad: Use IDR for agent IDs Message-ID: <20180613073653.GC3275@mtr-leonro.mtl.com> References: <20180608174218.32455-1-willy@infradead.org> <20180608174218.32455-3-willy@infradead.org> <20180612203322.GG6314@ziepe.ca> <20180613000739.GA32191@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1UWUbFP1cBYEclgG" Content-Disposition: inline In-Reply-To: <20180613000739.GA32191@bombadil.infradead.org> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --1UWUbFP1cBYEclgG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Jun 12, 2018 at 05:07:39PM -0700, Matthew Wilcox wrote: > On Tue, Jun 12, 2018 at 02:33:22PM -0600, Jason Gunthorpe wrote: > > > @@ -377,13 +378,24 @@ struct ib_mad_agent *ib_register_mad_agent(struct ib_device *device, > > > goto error4; > > > } > > > > > > - spin_lock_irq(&port_priv->reg_lock); > > > - mad_agent_priv->agent.hi_tid = atomic_inc_return(&ib_mad_client_id); > > > + idr_preload(GFP_KERNEL); > > > + idr_lock(&ib_mad_clients); > > > + ret2 = idr_alloc_cyclic(&ib_mad_clients, mad_agent_priv, 0, > > > + (1 << 24), GFP_ATOMIC); > > > > I like this series, my only concern is this magic number here, at the > > very least it deserves a big comment explaining why it > > exists.. > > Yes, you're right. Maybe something like this ... > > /* > * The mlx4 driver uses the top byte to distinguish which virtual function > * generated the MAD, so we must avoid using it. > */ > #define AGENT_ID_LIMIT (1 << 24) > > ... > > ret2 = idr_alloc_cyclic(&ib_mad_clients, mad_agent_priv, 0, > AGENT_ID_LIMIT, GFP_ATOMIC); > > > Let me see if I can get someone to give it some test time, I assume > > you haven't been able to test it it? > > I don't have any IB hardware. Frankly I'm scared of Infiniband ;-) I took it for regression, reliable results will be after -rc1 only. 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