From owner-svn-src-all@freebsd.org Wed Dec 2 17:48:28 2020 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id A48294A2040; Wed, 2 Dec 2020 17:48:28 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4CmRK824LGz3M6S; Wed, 2 Dec 2020 17:48:27 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.16.1/8.16.1) with ESMTPS id 0B2HmKsi000870 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Wed, 2 Dec 2020 19:48:23 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 0B2HmKsi000870 Received: (from kostik@localhost) by tom.home (8.16.1/8.16.1/Submit) id 0B2HmK3d000869; Wed, 2 Dec 2020 19:48:20 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Wed, 2 Dec 2020 19:48:20 +0200 From: Konstantin Belousov To: Michal Meloun Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r368279 - head/sys/dev/nvme Message-ID: References: <202012021654.0B2GsOP8000763@repo.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202012021654.0B2GsOP8000763@repo.freebsd.org> X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on tom.home X-Rspamd-Queue-Id: 4CmRK824LGz3M6S X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Dec 2020 17:48:28 -0000 On Wed, Dec 02, 2020 at 04:54:24PM +0000, Michal Meloun wrote: > Author: mmel > Date: Wed Dec 2 16:54:24 2020 > New Revision: 368279 > URL: https://svnweb.freebsd.org/changeset/base/368279 > > Log: > NVME: Multiple busdma related fixes. ... > - in nvme_qpair_submit_tracker(), don't do explicit wmb() also for arm > and arm64. Bus_dmamap_sync() on these architectures is sufficient to ensure > that all CPU stores are visible to external (including DMA) observers. > @@ -982,7 +982,7 @@ nvme_qpair_submit_tracker(struct nvme_qpair *qpair, st > > bus_dmamap_sync(qpair->dma_tag, qpair->queuemem_map, > BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE); > -#ifndef __powerpc__ > +#if !defined( __powerpc__) && !defined( __aarch64__) && !defined( __arm__) > /* > * powerpc's bus_dmamap_sync() already includes a heavyweight sync, but > * no other archs do. Does anybody have any evidence that the wmb() below is useful ? For instance, on x86, does nvme driver use any write-combining mappings ?