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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 268C4C742BD for ; Fri, 12 Jul 2019 13:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E46162080A for ; Fri, 12 Jul 2019 13:19:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="uNpMthTv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727430AbfGLNTe (ORCPT ); Fri, 12 Jul 2019 09:19:34 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:41612 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727363AbfGLNTe (ORCPT ); Fri, 12 Jul 2019 09:19:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=+B8h4Iz6ru/chORA1eax9a8LOD242SI/Y9Vwa/AMfAc=; b=uNpMthTv5WiPKImJMY7yrm8f9 ugaiYOydOgutz9+Qeha+7aq6QZdbe+iwIdaD2KR7yXSBLK5P4KMm4n/vx1G1bQ69NR/HpagCuGR8T taWweVNCxzr/xoFgH2AfmLgNNYEhHbMb1WXDEbeDpWbMZo77D2shcue6HVmoXnHVRA9BcLgzZlx28 4UEFzd0+X5BxhUfwBjJt95/2q/vBSKgqtu+z9saWEHI23HXrWOl5wWwd6wOfeVClxDLt3rfxXnUva LHk3AM6H4D4iiHDE2nvJ/dT/czNHpAb8x8RS7YJzdFkuRP19IaWc96ZNP69Vb4CeYBOzAnoqZK33C sARK7gg7Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hlvSW-0002zt-SV; Fri, 12 Jul 2019 13:19:33 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 03C4C209772E6; Fri, 12 Jul 2019 15:19:30 +0200 (CEST) Date: Fri, 12 Jul 2019 15:19:30 +0200 From: Peter Zijlstra To: Bernard Metzler Cc: Jason Gunthorpe , Arnd Bergmann , Doug Ledford , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Re: [PATCH] rdma/siw: avoid smp_store_mb() on a u64 Message-ID: <20190712131930.GT3419@hirez.programming.kicks-ass.net> References: <20190712120328.GB27512@ziepe.ca> <20190712085212.3901785-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Jul 12, 2019 at 01:05:14PM +0000, Bernard Metzler wrote: > @@ -1131,6 +1131,10 @@ int siw_poll_cq(struct ib_cq *base_cq, int num_cqe, struct ib_wc *wc) > * number of not reaped CQE's regardless of its notification > * type and current or new CQ notification settings. > * > + * This function gets called only by kernel consumers. > + * Notification state must immediately become visible to all > + * associated kernel producers (QP's). No amount of memory barriers can achieve that goal.