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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E479CA9EAF for ; Thu, 24 Oct 2019 23:53:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5DFFC206DD for ; Thu, 24 Oct 2019 23:53:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="M8sIjZgC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732581AbfJXXxG (ORCPT ); Thu, 24 Oct 2019 19:53:06 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:35391 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727309AbfJXXxG (ORCPT ); Thu, 24 Oct 2019 19:53:06 -0400 Received: by mail-qt1-f194.google.com with SMTP id m15so616418qtq.2 for ; Thu, 24 Oct 2019 16:53:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=O5YWlVDMQQRj45NieJDAfnNmrT+kDKmjnDW5sX3377E=; b=M8sIjZgCpj/RC02Il1V95dTxoqAQiPY636++cOfuRNqRyxKTUgJQXLNRmoRm1lTHz8 7wUkLhdhTz/Nk7QKxR/NnJy2kYeEt9gn34MO1U1gyxDKxvG2qu2mXZWdBdHFvOq2AXfC ZMFONbpJT/XZzZ5h2/YwJa6kaFkKx15PKCoVU2r56PUvPc5P9QSc/zlTOebjYswPmpYl PM7gxsiJXowTtWTOJjudVeDrU6m21ZtvfK0Yhsv0jgsVPBY+MhJi/FsLpn+1svBlUzdq OfoWJH53M12uodsgFnL1aO/dFsUJ/JlNRghhBq0GtHrPB9A3DIkKyFqejOXF8oeufkVN W6HA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=O5YWlVDMQQRj45NieJDAfnNmrT+kDKmjnDW5sX3377E=; b=fIHvMomPDo/hsTOz5PfFvFQaYs6MoTCOds92aRxafqLxId1IYnACUBeAlGMkyATeXJ bsCoPqZqSxk6aordwqBbHAXe2aYO+LwvNe9SRCxvQ6HdxsFWaazLzSD7QuATB8/cEMOl 5/dS2DmemX6Q/aosvEJaMdRZ9YJVf8Q36CCA/vzq9WVnU8Uz4aZYPB+PVXlA24AQs/bG j4+Ssc6OSZfG/EDBJsH20yG0/Ko+8KNjThrfQPaIzVh4ugBFk1Ga/NDbotO0/8/pt86g 1srqk4mFEs3xKUV0MLJY7f/5KXdtMlMjhJZ7cyF5sUK6W3ccPbwf2f2gL4FdIPGIZjXj BHAA== X-Gm-Message-State: APjAAAWHbgBWa9iDgQ1nDxn2d69MK0FCoChaSRGMor+J9KvNbZBKvjIe 2Dgu5O5JEZsxZ730TJEyG8LL1SCapA8= X-Google-Smtp-Source: APXvYqwoamvYagh6PuT1LwHoJV9Bpn0dLeuM5XSAV84M4bCmDI65/j4yWQ2w7tqcPQMx4tzmrAYaJA== X-Received: by 2002:a0c:887a:: with SMTP id 55mr570850qvm.137.1571961185527; Thu, 24 Oct 2019 16:53:05 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-162-113-180.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.180]) by smtp.gmail.com with ESMTPSA id x26sm254388qto.21.2019.10.24.16.53.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 24 Oct 2019 16:53:04 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iNmue-0000h4-Ck; Thu, 24 Oct 2019 20:53:04 -0300 Date: Thu, 24 Oct 2019 20:53:04 -0300 From: Jason Gunthorpe To: Parav Pandit Cc: Leon Romanovsky , Doug Ledford , RDMA mailing list Subject: Re: [PATCH rdma-next] IB/core: Avoid deadlock during netlink message handling Message-ID: <20191024235304.GG23952@ziepe.ca> References: <20191024131743.GA24174@ziepe.ca> <20191024132607.GR4853@unreal> <20191024135017.GT23952@ziepe.ca> <20191024160252.GS4853@unreal> <20191024160810.GV23952@ziepe.ca> <20191024161305.GU4853@unreal> <20191024183639.GA23952@ziepe.ca> <20191024191947.GV4853@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Thu, Oct 24, 2019 at 07:53:56PM +0000, Parav Pandit wrote: > Jason's memory size point made be curious about the srcu_struct > size. On my x86 5.x kernel I see srcu_struct costs 70+Kbytes! > Likely due to some debug info in my kernel. Which is probably a > good reason in this case to shift to rwsem. (rwsem is 80 bytes). Yikes, I knew it was bad, but I didn't think that bad.. So unbelievable I checked here and I got +4752 bytes using SRCU on my much less debug kernel. Crazy. > One small comment correction needed is, > > - rdma_nl_types[index].cb_table = cb_table; > - mutex_unlock(&rdma_nl_mutex); > + /* Pairs with the READ_ONCE in is_nl_valid() */ > + smp_store_release(&rdma_nl_types[index].cb_table, cb_table); > > It should be "Pairs with the READ_ONE in get_cb_table() */ Done, applied to for-rc, thanks Jason