From: Avi Kivity <avi@redhat.com>
To: Gregory Haskins <ghaskins@novell.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
linux-kernel@vger.kernel.org, agraf@suse.de,
pmullaney@novell.com, pmorreale@novell.com,
anthony@codemonkey.ws, rusty@rustcorp.com.au,
netdev@vger.kernel.org, kvm@vger.kernel.org,
bhutchings@solarflare.com, andi@firstfloor.org, gregkh@suse.de,
herber@gondor.apana.org.au, chrisw@sous-sol.org,
shemminger@vyatta.com
Subject: Re: [RFC PATCH v2 03/19] vbus: add connection-client helper infrastructure
Date: Thu, 04 Jun 2009 21:24:33 +0300 [thread overview]
Message-ID: <4A281161.8010109@redhat.com> (raw)
In-Reply-To: <4A280FE2.2090101@novell.com>
Gregory Haskins wrote:
>> BTW, why did you decide to use get_user_pages?
>> Would switch_mm + copy_to_user work as well
>> avoiding page walk if all pages are present?
>>
>>
>
> Well, basic c_t_u() won't work because its likely not "current" if you
> are updating the ring from some other task, but I think you have already
> figured that out based on the switch_mm suggestion. The simple truth is
> I was not familiar with switch_mm at the time I wrote this (nor am I
> now). If this is a superior method that allows you to acquire
> c_t_u(some_other_ctx) like behavior, I see no problem in changing. I
> will look into this, and thanks for the suggestion!
>
copy_to_user() is significantly faster than get_user_pages() + kmap() +
memcmp() (or their variants).
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2009-06-04 18:25 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-09 16:30 [RFC PATCH v2 00/19] virtual-bus Gregory Haskins
2009-04-09 16:30 ` [RFC PATCH v2 01/19] shm-signal: shared-memory signals Gregory Haskins
2009-04-09 16:30 ` [RFC PATCH v2 02/19] vbus: add virtual-bus definitions Gregory Haskins
2009-04-09 16:30 ` [RFC PATCH v2 03/19] vbus: add connection-client helper infrastructure Gregory Haskins
2009-06-04 18:06 ` Michael S. Tsirkin
2009-06-04 18:18 ` Gregory Haskins
2009-06-04 18:24 ` Avi Kivity [this message]
2009-06-04 18:30 ` Gregory Haskins
2009-06-04 19:04 ` Avi Kivity
2009-06-04 18:23 ` Avi Kivity
2009-04-09 16:31 ` [RFC PATCH v2 04/19] vbus: add bus-registration notifiers Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 05/19] vbus: add a "vbus-proxy" bus model for vbus_driver objects Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 06/19] ioq: Add basic definitions for a shared-memory, lockless queue Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 07/19] ioq: add vbus helpers Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 08/19] venet: add the ABI definitions for an 802.x packet interface Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 09/19] net: Add vbus_enet driver Gregory Haskins
2009-04-09 16:37 ` Stephen Hemminger
2009-04-09 19:50 ` Greg KH
2009-04-09 16:31 ` [RFC PATCH v2 10/19] venet-tap: Adds a "venet" compatible "tap" device to VBUS Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 11/19] venet: add scatter-gather support Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 12/19] venettap: " Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 13/19] x86: allow the irq->vector translation to be determined outside of ioapic Gregory Haskins
2009-04-09 16:31 ` [RFC PATCH v2 14/19] kvm: add a reset capability Gregory Haskins
2009-04-11 16:56 ` Avi Kivity
2009-04-09 16:32 ` [RFC PATCH v2 15/19] kvm: add dynamic IRQ support Gregory Haskins
2009-04-11 17:01 ` Avi Kivity
2009-04-13 17:44 ` Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 16/19] kvm: Add VBUS support to the host Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 17/19] kvm: Add guest-side support for VBUS Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 18/19] vbus: add a userspace connector Gregory Haskins
2009-04-09 16:32 ` [RFC PATCH v2 19/19] virtio: add a vbus transport Gregory Haskins
2009-08-09 16:40 ` Anthony Liguori
2009-08-10 15:40 ` Gregory Haskins
2009-04-09 16:48 ` [RFC PATCH v2 00/19] virtual-bus Gregory Haskins
2009-04-11 16:45 ` Avi Kivity
2009-06-04 18:49 ` Gregory Haskins
2009-06-05 4:55 ` Rusty Russell
2009-06-05 5:30 ` Paul E. McKenney
2009-06-05 14:55 ` Rusty Russell
2009-06-05 16:25 ` Paul E. McKenney
2009-06-11 13:21 ` Rusty Russell
2009-06-11 15:48 ` Paul E. McKenney
2009-06-05 11:56 ` Gregory Haskins
2009-06-05 12:53 ` Avi Kivity
2009-06-05 12:54 ` Gregory Haskins
2009-06-05 13:35 ` [PATCH] kvm: make sure we select EVENTFD for any arch that declares HAVE_KVM_EVENTFD Gregory Haskins
2009-06-08 8:56 ` Avi Kivity
2009-06-05 14:35 ` [RFC PATCH v2 00/19] virtual-bus Rusty Russell
2009-06-05 14:44 ` Gregory Haskins
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