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From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	peterx@redhat.com, linux-mm@kvack.org,
	Jerome Glisse <jglisse@redhat.com>
Subject: Re: [RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address
Date: Tue, 12 Mar 2019 15:15:22 +0800	[thread overview]
Message-ID: <3b00dc4a-b1b7-aa3f-c4ba-515138e4d6dd@redhat.com> (raw)
In-Reply-To: <20190311234956-mutt-send-email-mst@kernel.org>


On 2019/3/12 上午11:50, Michael S. Tsirkin wrote:
>>>> Using direct mapping (I
>>>> guess kernel will always try hugepage for that?) should be better and we can
>>>> even use it for the data transfer not only for the metadata.
>>>>
>>>> Thanks
>>> We can't really. The big issue is get user pages. Doing that on data
>>> path will be slower than copyXuser.
>> I meant if we can find a way to avoid doing gup in datapath. E.g vhost
>> maintain a range tree and add or remove ranges through MMU notifier. Then in
>> datapath, if we find the range, then use direct mapping otherwise
>> copy_to_user().
>>
>> Thanks
> We can try. But I'm not sure there's any reason to think there's any
> locality there.
>

Ok, but what kind of locality do you mean here?

Thanks


  reply	other threads:[~2019-03-12  7:15 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-06  7:18 [RFC PATCH V2 0/5] vhost: accelerate metadata access through vmap() Jason Wang
2019-03-06  7:18 ` [RFC PATCH V2 1/5] vhost: generalize adding used elem Jason Wang
2019-03-06  7:18 ` [RFC PATCH V2 2/5] vhost: fine grain userspace memory accessors Jason Wang
2019-03-06 10:45   ` Christophe de Dinechin
2019-03-07  2:38     ` Jason Wang
2019-03-06  7:18 ` [RFC PATCH V2 3/5] vhost: rename vq_iotlb_prefetch() to vq_meta_prefetch() Jason Wang
2019-03-06  7:18 ` [RFC PATCH V2 4/5] vhost: introduce helpers to get the size of metadata area Jason Wang
2019-03-06 10:56   ` Christophe de Dinechin
2019-03-07  2:40     ` Jason Wang
2019-03-06 18:43   ` Souptick Joarder
2019-03-07  2:42     ` Jason Wang
2019-03-06  7:18 ` [RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address Jason Wang
2019-03-06 16:31   ` Michael S. Tsirkin
2019-03-07  2:45     ` Jason Wang
2019-03-07 15:34       ` Michael S. Tsirkin
2019-03-07 19:09         ` Jerome Glisse
2019-03-07 19:38           ` Andrea Arcangeli
2019-03-07 20:17             ` Jerome Glisse
2019-03-07 21:27               ` Andrea Arcangeli
2019-03-08  9:13                 ` Jason Wang
2019-03-08 19:11                   ` Andrea Arcangeli
2019-03-11  7:21                     ` Jason Wang
2019-03-11 14:45                 ` Jan Kara
2019-03-08  8:31         ` Jason Wang
2019-03-07 15:47   ` Michael S. Tsirkin
2019-03-07 17:56     ` Michael S. Tsirkin
2019-03-07 19:16       ` Andrea Arcangeli
2019-03-08  8:50         ` Jason Wang
2019-03-08 14:58           ` Jerome Glisse
2019-03-11  7:18             ` Jason Wang
2019-03-08 19:48           ` Andrea Arcangeli
2019-03-08 20:06             ` Jerome Glisse
2019-03-11  7:40             ` Jason Wang
2019-03-11 12:48               ` Michael S. Tsirkin
2019-03-11 13:43                 ` Andrea Arcangeli
2019-03-12  2:56                   ` Jason Wang
2019-03-12  3:51                     ` Michael S. Tsirkin
2019-03-12  2:52                 ` Jason Wang
2019-03-12  3:50                   ` Michael S. Tsirkin
2019-03-12  7:15                     ` Jason Wang [this message]
2019-03-07 19:17       ` Jerome Glisse
2019-03-08  2:21         ` Michael S. Tsirkin
2019-03-08  2:55           ` Jerome Glisse
2019-03-08  3:16             ` Michael S. Tsirkin
2019-03-08  3:40               ` Jerome Glisse
2019-03-08  3:43                 ` Michael S. Tsirkin
2019-03-08  3:45                   ` Jerome Glisse
2019-03-08  9:15                     ` Jason Wang
2019-03-08  8:58         ` Jason Wang
2019-03-08 12:56           ` Michael S. Tsirkin
2019-03-08 15:02             ` Jerome Glisse
2019-03-08 19:13           ` Andrea Arcangeli
2019-03-08 14:12 ` [RFC PATCH V2 0/5] vhost: accelerate metadata access through vmap() Christoph Hellwig
2019-03-11  7:13   ` Jason Wang
2019-03-11 13:59     ` Michael S. Tsirkin
2019-03-11 18:14       ` David Miller
2019-03-12  2:59         ` Jason Wang
2019-03-12  3:52           ` Michael S. Tsirkin
2019-03-12  7:17             ` Jason Wang
2019-03-12 11:54               ` Michael S. Tsirkin
2019-03-12 15:46                 ` James Bottomley
2019-03-12 20:04                   ` Andrea Arcangeli
2019-03-12 20:53                     ` James Bottomley
2019-03-12 21:11                       ` Andrea Arcangeli
2019-03-12 21:19                         ` James Bottomley
2019-03-12 21:53                           ` Andrea Arcangeli
2019-03-12 22:02                             ` James Bottomley
2019-03-12 22:50                               ` Andrea Arcangeli
2019-03-12 22:57                                 ` James Bottomley
2019-03-13 16:05                       ` Christoph Hellwig
2019-03-13 16:37                         ` James Bottomley
2019-03-14 10:42                           ` Michael S. Tsirkin
2019-03-14 13:49                             ` Jason Wang
2019-03-14 19:33                               ` Andrea Arcangeli
2019-03-15  4:39                                 ` Jason Wang
2019-03-12  5:14           ` James Bottomley
2019-03-12  7:51             ` Jason Wang
2019-03-12  7:53               ` Jason Wang

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