From: "Xie, Huawei" <huawei.xie@intel.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"dev@dpdk.org" <dev@dpdk.org>,
Victor Kaplansky <vkaplans@redhat.com>
Subject: Re: [dpdk-dev] [PATCH v2 2/6] vhost: introduce vhost_log_write
Date: Tue, 22 Dec 2015 07:02:10 +0000 [thread overview]
Message-ID: <C37D651A908B024F974696C65296B57B4C5511C1@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <20151222030432.GG18863@yliu-dev.sh.intel.com>
On 12/22/2015 11:03 AM, Yuanhan Liu wrote:
> On Tue, Dec 22, 2015 at 02:45:52AM +0000, Xie, Huawei wrote:
>>>>> +static inline void __attribute__((always_inline))
>>>>> +vhost_log_write(struct virtio_net *dev, uint64_t addr, uint64_t len)
>>>>> +{
>>>>> + uint64_t page;
>>>>> +
>>>> Before we log, we need memory barrier to make sure updates are in place.
>>>>> + if (likely(((dev->features & (1ULL << VHOST_F_LOG_ALL)) == 0) ||
>>>>> + !dev->log_base || !len))
>>>>> + return;
>>> Put a memory barrier inside set_features()?
>>>
>>> I see no var dependence here, why putting a barrier then? We are
>>> accessing and modifying same var, doesn't the cache MESI protocol
>>> will get rid of your concerns?
>> This fence isn't about feature var. It is to ensure that updates to the
>> guest buffer are committed before the logging.
> Oh.., I was thinking you were talking about the "dev->features" field
> concurrent access and modify you mentioned from V1.
>
>> For IA strong memory model, compiler barrier is enough. For other weak
>> memory model, fence is required.
>>>>> +
>>>>> + if (unlikely(dev->log_size < ((addr + len - 1) / VHOST_LOG_PAGE / 8)))
>>>>> + return;
> So that I should put a "rte_mb()" __here__?
>
> --yliu
I find that we already have the arch dependent version of rte_smp_wmb()
--huawei
>>>>> +
>>>>> + page = addr / VHOST_LOG_PAGE;
>>>>> + while (page * VHOST_LOG_PAGE < addr + len) {
>>>> Let us have a page_end var to make the code simpler?
>>> Could do that.
>>>
>>>
>>>>> + vhost_log_page((uint8_t *)(uintptr_t)dev->log_base, page);
>>>>> + page += VHOST_LOG_PAGE;
>>>> page += 1?
>>> Oops, right.
>>>
>>> --yliu
>>>
>>>>> + }
>>>>> +}
>>>>> +
>>>>> +
>>>>> /**
>>>>> * Disable features in feature_mask. Returns 0 on success.
>>>>> */
next prev parent reply other threads:[~2015-12-22 7:02 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-02 3:43 [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support Yuanhan Liu
2015-12-02 3:43 ` [dpdk-dev] [PATCH 1/4] vhost: handle VHOST_USER_SET_LOG_BASE request Yuanhan Liu
2015-12-02 13:53 ` Panu Matilainen
2015-12-02 14:31 ` Yuanhan Liu
2015-12-02 14:48 ` Panu Matilainen
2015-12-02 15:09 ` Yuanhan Liu
2015-12-02 16:58 ` Panu Matilainen
2015-12-02 17:24 ` Michael S. Tsirkin
2015-12-02 16:38 ` Thomas Monjalon
2015-12-03 1:49 ` Yuanhan Liu
2015-12-06 23:07 ` Thomas Monjalon
2015-12-07 2:00 ` Yuanhan Liu
2015-12-07 2:03 ` Thomas Monjalon
2015-12-07 2:18 ` Yuanhan Liu
2015-12-07 2:49 ` Thomas Monjalon
2015-12-07 6:29 ` Panu Matilainen
2015-12-07 11:28 ` Thomas Monjalon
2015-12-07 11:41 ` Panu Matilainen
2015-12-07 13:55 ` Thomas Monjalon
2015-12-07 16:48 ` Panu Matilainen
2015-12-07 17:47 ` Thomas Monjalon
2015-12-08 5:57 ` Xie, Huawei
2015-12-08 7:25 ` Yuanhan Liu
2015-12-02 3:43 ` [dpdk-dev] [PATCH 2/4] vhost: introduce vhost_log_write Yuanhan Liu
2015-12-02 13:53 ` Victor Kaplansky
2015-12-02 14:39 ` Yuanhan Liu
2015-12-09 3:33 ` Xie, Huawei
2015-12-09 3:42 ` Yuanhan Liu
2015-12-09 5:44 ` Xie, Huawei
2015-12-09 8:41 ` Yuanhan Liu
2015-12-02 3:43 ` [dpdk-dev] [PATCH 3/4] vhost: log vring changes Yuanhan Liu
2015-12-02 14:07 ` Victor Kaplansky
2015-12-02 14:38 ` Yuanhan Liu
2015-12-02 15:58 ` Victor Kaplansky
2015-12-02 16:26 ` Michael S. Tsirkin
2015-12-03 2:31 ` Yuanhan Liu
2015-12-09 2:45 ` Xie, Huawei
2015-12-02 3:43 ` [dpdk-dev] [PATCH 4/4] vhost: enable log_shmfd protocol feature Yuanhan Liu
2015-12-02 14:10 ` [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support Victor Kaplansky
2015-12-02 14:33 ` Yuanhan Liu
2015-12-09 3:41 ` Xie, Huawei
2015-12-17 3:11 ` [dpdk-dev] [PATCH v2 0/6] " Yuanhan Liu
2015-12-17 3:11 ` [dpdk-dev] [PATCH v2 1/6] vhost: handle VHOST_USER_SET_LOG_BASE request Yuanhan Liu
2015-12-21 15:32 ` Xie, Huawei
2015-12-22 2:25 ` Yuanhan Liu
2015-12-22 2:41 ` Xie, Huawei
2015-12-22 2:55 ` Yuanhan Liu
2015-12-17 3:11 ` [dpdk-dev] [PATCH v2 2/6] vhost: introduce vhost_log_write Yuanhan Liu
2015-12-21 15:06 ` Xie, Huawei
2015-12-22 2:40 ` Yuanhan Liu
2015-12-22 2:45 ` Xie, Huawei
2015-12-22 3:04 ` Yuanhan Liu
2015-12-22 7:02 ` Xie, Huawei [this message]
2015-12-22 5:11 ` Peter Xu
2015-12-22 6:09 ` Yuanhan Liu
2015-12-17 3:11 ` [dpdk-dev] [PATCH v2 3/6] vhost: log used vring changes Yuanhan Liu
2015-12-22 6:55 ` Peter Xu
2015-12-22 7:07 ` Xie, Huawei
2015-12-22 7:59 ` Peter Xu
2015-12-22 7:13 ` Yuanhan Liu
2015-12-22 8:01 ` Peter Xu
2015-12-17 3:11 ` [dpdk-dev] [PATCH v2 4/6] vhost: log vring desc buffer changes Yuanhan Liu
2015-12-17 3:12 ` [dpdk-dev] [PATCH v2 5/6] vhost: claim that we support GUEST_ANNOUNCE feature Yuanhan Liu
2015-12-22 8:11 ` Peter Xu
2015-12-22 8:21 ` Yuanhan Liu
2015-12-22 8:24 ` Pavel Fedin
2015-12-17 3:12 ` [dpdk-dev] [PATCH v2 6/6] vhost: enable log_shmfd protocol feature Yuanhan Liu
2015-12-17 12:08 ` [dpdk-dev] [PATCH v2 0/6] vhost-user live migration support Iremonger, Bernard
2015-12-17 12:45 ` Yuanhan Liu
2015-12-21 8:17 ` Pavel Fedin
2016-01-29 4:57 ` [dpdk-dev] [PATCH v3 0/8] " Yuanhan Liu
2016-01-29 4:57 ` [dpdk-dev] [PATCH v3 1/8] vhost: handle VHOST_USER_SET_LOG_BASE request Yuanhan Liu
2016-01-29 4:57 ` [dpdk-dev] [PATCH v3 2/8] vhost: introduce vhost_log_write Yuanhan Liu
2016-02-19 14:26 ` Thomas Monjalon
2016-02-22 6:59 ` Yuanhan Liu
2016-01-29 4:57 ` [dpdk-dev] [PATCH v3 3/8] vhost: log used vring changes Yuanhan Liu
2016-01-29 4:57 ` [dpdk-dev] [PATCH v3 4/8] vhost: log vring desc buffer changes Yuanhan Liu
2016-01-29 4:58 ` [dpdk-dev] [PATCH v3 5/8] vhost: claim that we support GUEST_ANNOUNCE feature Yuanhan Liu
2016-03-11 12:39 ` Olivier MATZ
2016-03-11 13:16 ` Thomas Monjalon
2016-03-11 13:22 ` Olivier MATZ
2016-01-29 4:58 ` [dpdk-dev] [PATCH v3 6/8] vhost: handle VHOST_USER_SEND_RARP request Yuanhan Liu
2016-02-19 6:11 ` Tan, Jianfeng
2016-02-19 7:03 ` Yuanhan Liu
2016-02-19 8:55 ` Yuanhan Liu
2016-02-22 14:36 ` [dpdk-dev] [PATCH] vhost: broadcast RARP pkt by injecting it to receiving mbuf array Yuanhan Liu
2016-02-24 8:15 ` Qiu, Michael
2016-02-24 8:28 ` Yuanhan Liu
2016-02-25 7:55 ` Qiu, Michael
2016-02-29 15:56 ` Thomas Monjalon
2016-01-29 4:58 ` [dpdk-dev] [PATCH v3 7/8] vhost: enable log_shmfd protocol feature Yuanhan Liu
2016-01-29 4:58 ` [dpdk-dev] [PATCH v3 8/8] vhost: remove duplicate header include Yuanhan Liu
2016-02-01 15:54 ` [dpdk-dev] [PATCH v3 0/8] vhost-user live migration support Iremonger, Bernard
2016-02-02 1:53 ` Yuanhan Liu
2016-02-19 15:01 ` Thomas Monjalon
2016-02-22 7:08 ` Yuanhan Liu
2016-02-22 9:56 ` Thomas Monjalon
2016-02-22 14:24 ` Yuanhan Liu
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