From: "Michael S. Tsirkin" <mst@redhat.com>
To: Gregory Haskins <ghaskins@novell.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
avi@redhat.com, davidel@xmailserver.org,
paulmck@linux.vnet.ibm.com, mingo@elte.hu
Subject: Re: [KVM-RFC PATCH 1/2] eventfd: add an explicit srcu based notifier interface
Date: Wed, 17 Jun 2009 17:45:40 +0300 [thread overview]
Message-ID: <20090617144540.GB3089@redhat.com> (raw)
In-Reply-To: <4A37DFE2.2020506@novell.com>
On Tue, Jun 16, 2009 at 02:09:38PM -0400, Gregory Haskins wrote:
> > What do you mean by copy_to_user(other->mm) here? If you are going to switch
> > to another mm, then I think current->mm must be valid (I think it's not enough
> > that you can sleep). So preemptible() might not be enough.
> >
>
> I dont currently use switch_mm, if that is what you mean. I save the
> task_struct into the appropriate context so current->mm doesn't matter
> to me. I never use it. All I need (afaik) is to acquire the proper
> mutex first. I am not an MM expert, so perhaps I have this wrong but it
> does appear to work properly even from kthread context.
>
> -Greg
>
>
I think I saw get_user_pages + memcpy in your patch. Yes, that works
without switching contexts but it's slower than copy to user if you are
in the right context, and AFAIK it's slower than get_user_pages_fast.
--
MST
next prev parent reply other threads:[~2009-06-17 14:46 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 2:29 [KVM-RFC PATCH 0/2] eventfd enhancements for irqfd/iosignalfd Gregory Haskins
2009-06-16 2:29 ` [KVM-RFC PATCH 1/2] eventfd: add an explicit srcu based notifier interface Gregory Haskins
2009-06-16 14:02 ` Michael S. Tsirkin
2009-06-16 14:11 ` Gregory Haskins
2009-06-16 14:38 ` Michael S. Tsirkin
2009-06-16 14:48 ` Gregory Haskins
2009-06-16 14:54 ` Gregory Haskins
2009-06-16 15:16 ` Michael S. Tsirkin
2009-06-16 14:55 ` Michael S. Tsirkin
2009-06-16 15:20 ` Gregory Haskins
2009-06-16 15:41 ` Michael S. Tsirkin
2009-06-16 16:17 ` Gregory Haskins
2009-06-16 16:19 ` Davide Libenzi
2009-06-16 17:01 ` Gregory Haskins
2009-06-17 16:38 ` Davide Libenzi
2009-06-17 17:28 ` Gregory Haskins
2009-06-17 17:44 ` Davide Libenzi
2009-06-17 19:17 ` Gregory Haskins
2009-06-17 19:50 ` Davide Libenzi
2009-06-17 21:48 ` Gregory Haskins
2009-06-17 23:21 ` Davide Libenzi
2009-06-18 6:23 ` Michael S. Tsirkin
2009-06-18 17:52 ` Davide Libenzi
2009-06-18 14:01 ` Gregory Haskins
2009-06-18 14:01 ` Gregory Haskins
2009-06-18 17:44 ` Davide Libenzi
2009-06-18 19:04 ` Gregory Haskins
2009-06-18 19:04 ` Gregory Haskins
2009-06-18 22:03 ` Davide Libenzi
2009-06-18 22:47 ` Gregory Haskins
2009-06-18 22:47 ` Gregory Haskins
2009-06-19 18:51 ` Gregory Haskins
2009-06-19 18:51 ` [PATCH 1/3] eventfd: Allow waiters to be notified about the eventfd file* going away Gregory Haskins
2009-06-19 18:51 ` [PATCH 2/3] eventfd: add generalized notifier interface Gregory Haskins
2009-06-19 18:51 ` [PATCH 3/3] eventfd: add internal reference counting to fix notifier race conditions Gregory Haskins
2009-06-19 19:10 ` Davide Libenzi
2009-06-19 21:16 ` Gregory Haskins
2009-06-19 21:26 ` Davide Libenzi
2009-06-19 21:49 ` Gregory Haskins
2009-06-19 21:54 ` Davide Libenzi
2009-06-19 22:47 ` Davide Libenzi
2009-06-20 2:09 ` Gregory Haskins
2009-06-20 21:17 ` Davide Libenzi
2009-06-20 22:11 ` Davide Libenzi
2009-06-20 23:48 ` Davide Libenzi
2009-06-21 1:14 ` Gregory Haskins
2009-06-21 16:51 ` Davide Libenzi
2009-06-21 18:39 ` Gregory Haskins
2009-06-21 23:54 ` Davide Libenzi
2009-06-22 16:05 ` Gregory Haskins
2009-06-22 16:05 ` Gregory Haskins
2009-06-22 17:01 ` Davide Libenzi
2009-06-22 17:43 ` Gregory Haskins
2009-06-22 17:43 ` Gregory Haskins
2009-06-22 18:03 ` Davide Libenzi
2009-06-22 18:31 ` Gregory Haskins
2009-06-22 18:31 ` Gregory Haskins
2009-06-22 18:40 ` Davide Libenzi
2009-06-22 18:41 ` Michael S. Tsirkin
2009-06-22 18:51 ` Davide Libenzi
2009-06-22 19:05 ` Michael S. Tsirkin
2009-06-22 19:26 ` Gregory Haskins
2009-06-22 19:29 ` Davide Libenzi
2009-06-22 20:06 ` Gregory Haskins
2009-06-22 22:53 ` Davide Libenzi
2009-06-23 1:03 ` Gregory Haskins
2009-06-23 1:17 ` Davide Libenzi
2009-06-23 1:26 ` Gregory Haskins
2009-06-23 1:26 ` Gregory Haskins
2009-06-23 14:29 ` Davide Libenzi
2009-06-23 14:37 ` Gregory Haskins
2009-06-23 14:37 ` Gregory Haskins
2009-06-23 14:35 ` Davide Libenzi
2009-06-23 14:42 ` Gregory Haskins
2009-06-23 14:42 ` Gregory Haskins
2009-06-23 15:04 ` Michael S. Tsirkin
2009-06-22 20:28 ` Michael S. Tsirkin
2009-06-22 19:16 ` Gregory Haskins
2009-06-22 19:54 ` Davide Libenzi
2009-06-24 3:25 ` Rusty Russell
2009-06-24 22:45 ` Davide Libenzi
2009-06-25 11:42 ` Rusty Russell
2009-06-25 16:34 ` Davide Libenzi
2009-06-25 17:32 ` Gregory Haskins
2009-06-25 18:26 ` Michael S. Tsirkin
2009-06-25 18:41 ` Gregory Haskins
2009-06-26 11:23 ` Michael S. Tsirkin
2009-06-23 3:25 ` Rusty Russell
2009-06-23 14:31 ` Davide Libenzi
2009-06-25 0:19 ` Davide Libenzi
2009-06-21 1:05 ` Gregory Haskins
2009-06-16 17:54 ` [KVM-RFC PATCH 1/2] eventfd: add an explicit srcu based notifier interface Michael S. Tsirkin
2009-06-16 18:09 ` Gregory Haskins
2009-06-17 14:45 ` Michael S. Tsirkin [this message]
2009-06-17 15:02 ` Gregory Haskins
2009-06-17 16:25 ` Michael S. Tsirkin
2009-06-17 16:41 ` Gregory Haskins
2009-06-16 14:17 ` Gregory Haskins
2009-06-16 14:22 ` Gregory Haskins
2009-06-16 14:40 ` Gregory Haskins
2009-06-16 14:46 ` Michael S. Tsirkin
2009-06-18 9:03 ` Avi Kivity
2009-06-18 11:43 ` Gregory Haskins
2009-06-16 2:30 ` [KVM-RFC PATCH 2/2] eventfd: add module reference counting support for registered notifiers Gregory Haskins
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