From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by dpdk.org (Postfix) with ESMTP id A4D4CE5D for ; Mon, 30 Apr 2018 16:44:52 +0200 (CEST) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1E7E88DC4C; Mon, 30 Apr 2018 14:44:52 +0000 (UTC) Received: from [10.36.112.35] (ovpn-112-35.ams2.redhat.com [10.36.112.35]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4EF442166BAD; Mon, 30 Apr 2018 14:44:51 +0000 (UTC) To: luca.boccassi@gmail.com Cc: Jianfeng Tan , dpdk stable References: <20180430140606.4615-80-luca.boccassi@gmail.com> <20180430144223.18657-1-luca.boccassi@gmail.com> <20180430144223.18657-5-luca.boccassi@gmail.com> From: Maxime Coquelin Message-ID: <242bac38-06ff-490a-df4a-f5734179ded6@redhat.com> Date: Mon, 30 Apr 2018 16:44:49 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180430144223.18657-5-luca.boccassi@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 30 Apr 2018 14:44:52 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 30 Apr 2018 14:44:52 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'maxime.coquelin@redhat.com' RCPT:'' Subject: Re: [dpdk-stable] patch 'vhost: avoid concurrency when logging dirty pages' has been queued to stable release 18.02.2 X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 30 Apr 2018 14:44:53 -0000 Hi Luca, Please don't backport this patch to -stable releases. It has already been reverted in upstream master, and a new patch is to be posted in the coming hours. I already notified Yuanhan for the same for v17.11 LTS. Thanks, Maxime On 04/30/2018 04:40 PM, luca.boccassi@gmail.com wrote: > Hi, > > FYI, your patch has been queued to stable release 18.02.2 > > Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet. > It will be pushed if I get no objections before 05/02/18. So please > shout if anyone has objections. > > Thanks. > > Luca Boccassi > > --- > From a5d642c446cc3a3be41694715d99f3e9f9ea44df Mon Sep 17 00:00:00 2001 > From: Maxime Coquelin > Date: Wed, 21 Mar 2018 16:44:13 +0100 > Subject: [PATCH] vhost: avoid concurrency when logging dirty pages > > [ upstream commit 394313fff39d0f994325c47f7eab39daf5dc9e11 ] > > This patch aims at fixing a migration performance regression > faced since atomic operation is used to log pages as dirty when > doing live migration. > > Instead of setting a single bit by doing an atomic read-modify-write > operation to log a page as dirty, this patch write 0xFF to the > corresponding byte, and so logs 8 page as dirty. > > The advantage is that it avoids concurrent atomic operations by > multiple PMD threads, the drawback is that some clean pages are > marked as dirty and so are transferred twice. > > Fixes: 897f13a1f726 ("vhost: make page logging atomic") > > Signed-off-by: Maxime Coquelin > Reviewed-by: Jianfeng Tan > --- > lib/librte_vhost/vhost.h | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > index bab0b456e..a4f23f714 100644 > --- a/lib/librte_vhost/vhost.h > +++ b/lib/librte_vhost/vhost.h > @@ -247,18 +247,14 @@ struct virtio_net { > #define VHOST_LOG_PAGE 4096 > > /* > - * Atomically set a bit in memory. > + * Mark all pages belonging to the same dirty log bitmap byte > + * as dirty. The goal is to avoid concurrency between different > + * threads doing atomic read-modify-writes on the same byte. > */ > -static __rte_always_inline void > -vhost_set_bit(unsigned int nr, volatile uint8_t *addr) > -{ > - __sync_fetch_and_or_8(addr, (1U << nr)); > -} > - > static __rte_always_inline void > vhost_log_page(uint8_t *log_base, uint64_t page) > { > - vhost_set_bit(page % 8, &log_base[page / 8]); > + log_base[page / 8] = 0xff; > } > > static __rte_always_inline void >