From: Avi Kivity <avi@redhat.com>
To: Shirley Ma <mashirle@us.ibm.com>
Cc: xiaohui.xin@intel.com, netdev@vger.kernel.org,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
mst@redhat.com, mingo@elte.hu, davem@davemloft.net,
herbert@gondor.hengli.com.au, jdike@linux.intel.com
Subject: Re: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net.
Date: Mon, 02 Aug 2010 19:11:41 +0300 [thread overview]
Message-ID: <4C56EE3D.1050203@redhat.com> (raw)
In-Reply-To: <1280764918.22830.7.camel@localhost.localdomain>
On 08/02/2010 07:01 PM, Shirley Ma wrote:
> Hello Avi,
>
> On Sun, 2010-08-01 at 11:18 +0300, Avi Kivity wrote:
>> I don't understand. Under what conditions do you use
>> get_user_pages()
>> instead of get_user_pages_fast()? Why?
> The code always calls get_user_pages_fast, however, the page will be
> unpinned in skb_free if the same page is not used again for a new
> buffer. The reason for unpin the page is we don't want to pin all of the
> guest kernel memory(memory over commit).
That is fine.
> So get_user_pages_fast will
> call slow path get_user_pages.
I don't understand this. gup_fast() only calls gup() if the page is
swapped out or read-only.
> Your previous comment is suggesting to keep the page pinned for
> get_user_pages_fast fast path?
>
Right now I'm not sure I understand what's happening.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-08-02 16:12 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-29 11:14 [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 01/16] Add a new structure for skb buffer from external xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 02/16] Add a new struct for device to manipulate external buffer xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 03/16] Add a ndo_mp_port_prep func to net_device_ops xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 04/16] Add a function make external buffer owner to query capability xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 05/16] Add a function to indicate if device use external buffer xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 06/16] Use callback to deal with skb_release_data() specially xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 07/16] Modify netdev_alloc_page() to get external buffer xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 08/16] Modify netdev_free_page() to release " xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 09/16] Don't do skb recycle, if device use " xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 10/16] Add a hook to intercept external buffers from NIC driver xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 11/16] Add header file for mp device xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 13/16] Add a kconfig entry and make entry " xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 12/16] Add mp(mediate passthru) device xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 14/16] Provides multiple submits and asynchronous notifications xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 15/16] An example how to modifiy NIC driver to use napi_gro_frags() interface xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 11:14 ` [RFC PATCH v8 16/16] An example how to alloc user buffer based on " xiaohui.xin
2010-07-29 11:14 ` xiaohui.xin
2010-07-29 22:31 ` [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net Shirley Ma
2010-07-29 22:31 ` Shirley Ma
2010-07-30 5:02 ` Avi Kivity
2010-07-30 15:46 ` Shirley Ma
2010-08-01 8:18 ` Avi Kivity
2010-08-02 16:01 ` Shirley Ma
2010-08-02 16:11 ` Avi Kivity [this message]
2010-08-02 16:25 ` Shirley Ma
2010-08-02 16:32 ` Avi Kivity
2010-08-11 3:28 ` Shirley Ma
2010-07-30 8:53 ` Xin, Xiaohui
2010-07-30 8:53 ` Xin, Xiaohui
2010-07-30 15:51 ` Shirley Ma
2010-07-30 15:51 ` Shirley Ma
2010-07-31 9:30 ` Arnd Bergmann
2010-07-31 9:30 ` Arnd Bergmann
2010-08-04 2:06 ` Dong, Eddie
2010-08-04 2:06 ` Dong, Eddie
2010-08-04 8:56 ` Arnd Bergmann
2010-08-04 8:56 ` Arnd Bergmann
2010-08-04 17:09 ` Shirley Ma
2010-08-04 17:09 ` Shirley Ma
2010-08-01 8:31 ` Michael S. Tsirkin
2010-08-02 16:04 ` Shirley Ma
2010-08-02 16:10 ` Shirley Ma
2010-08-03 8:48 ` Xin, Xiaohui
2010-08-03 8:48 ` Xin, Xiaohui
2010-08-03 15:50 ` Shirley Ma
2010-08-03 15:50 ` Shirley Ma
2010-08-05 8:52 ` Xin, Xiaohui
2010-08-05 8:52 ` Xin, Xiaohui
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