From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jason Wang <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH V5 0/9] Fixes for vhost metadata acceleration
Date: Tue, 13 Aug 2019 09:41:05 -0700 [thread overview]
Message-ID: <20190813164105.GD22640@infradead.org> (raw)
In-Reply-To: <20190813115707.GC29508@ziepe.ca>
On Tue, Aug 13, 2019 at 08:57:07AM -0300, Jason Gunthorpe wrote:
> On Tue, Aug 13, 2019 at 04:31:07PM +0800, Jason Wang wrote:
>
> > What kind of issues do you see? Spinlock is to synchronize GUP with MMU
> > notifier in this series.
>
> A GUP that can't sleep can't pagefault which makes it a really weird
> pattern
get_user_pages/get_user_pages_fast must not be called under a spinlock.
We have the somewhat misnamed __get_user_page_fast that just does a
lookup for existing pages and never faults for a few places that need
to do that lookup from contexts where we can't sleep.
next prev parent reply other threads:[~2019-08-13 16:41 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 5:48 [PATCH V5 0/9] Fixes for vhost metadata acceleration Jason Wang
2019-08-09 5:48 ` [PATCH V5 1/9] vhost: don't set uaddr for invalid address Jason Wang
2019-08-09 5:48 ` [PATCH V5 2/9] vhost: validate MMU notifier registration Jason Wang
2019-08-09 5:48 ` [PATCH V5 3/9] vhost: fix vhost map leak Jason Wang
2019-08-09 5:48 ` [PATCH V5 4/9] vhost: reset invalidate_count in vhost_set_vring_num_addr() Jason Wang
2019-08-09 5:48 ` [PATCH V5 5/9] vhost: mark dirty pages during map uninit Jason Wang
2019-08-09 5:48 ` [PATCH V5 6/9] vhost: don't do synchronize_rcu() in vhost_uninit_vq_maps() Jason Wang
2019-08-09 5:48 ` [PATCH V5 7/9] vhost: do not use RCU to synchronize MMU notifier with worker Jason Wang
2019-08-09 5:48 ` [PATCH V5 8/9] vhost: correctly set dirty pages in MMU notifiers callback Jason Wang
2019-08-09 5:48 ` [PATCH V5 9/9] vhost: do not return -EAGAIN for non blocking invalidation too early Jason Wang
2019-08-10 17:52 ` [PATCH V5 0/9] Fixes for vhost metadata acceleration Michael S. Tsirkin
2019-08-12 2:44 ` Jason Wang
2019-08-12 4:13 ` David Miller
2019-08-12 9:49 ` Michael S. Tsirkin
2019-08-12 13:02 ` Jason Gunthorpe
2019-08-13 8:31 ` Jason Wang
2019-08-13 11:57 ` Jason Gunthorpe
2019-08-13 16:41 ` Christoph Hellwig [this message]
2019-08-15 3:28 ` Jason Wang
2019-08-15 3:26 ` Jason Wang
2019-08-15 19:33 ` Jason Gunthorpe
2019-08-13 8:12 ` Jason Wang
2019-08-19 21:08 ` Michael S. Tsirkin
2019-08-20 2:29 ` Jason Wang
2019-09-01 18:02 ` Michael S. Tsirkin
-- strict thread matches above, loose matches on Subject: below --
2019-08-07 7:06 [PATCH V4 0/9] Fixes for metadata accelreation Jason Wang
2019-08-07 7:06 ` [PATCH V4 7/9] vhost: do not use RCU to synchronize MMU notifier with worker Jason Wang
2019-08-07 12:07 ` Jason Gunthorpe
2019-08-07 14:02 ` Jason Wang
2019-08-08 12:54 ` Jason Wang
2019-08-10 19:12 ` [PATCH V5 0/9] Fixes for vhost metadata acceleration Michael S. Tsirkin
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