Re: [PATCH V2 net] Revert "vhost: cache used event for better performance"

2017-07-29 Thread David Miller
From: Jason Wang Date: Thu, 27 Jul 2017 11:22:05 +0800 > This reverts commit 809ecb9bca6a9424ccd392d67e368160f8b76c92. Since it > was reported to break vhost_net. We want to cache used event and use > it to check for notification. The assumption was that guest won't move > the event idx back, but

Re: [PATCH V2 net] Revert "vhost: cache used event for better performance"

2017-07-27 Thread Michael S. Tsirkin
On Thu, Jul 27, 2017 at 11:22:05AM +0800, Jason Wang wrote: > This reverts commit 809ecb9bca6a9424ccd392d67e368160f8b76c92. Since it > was reported to break vhost_net. We want to cache used event and use > it to check for notification. The assumption was that guest won't move > the event idx back,

[PATCH V2 net] Revert "vhost: cache used event for better performance"

2017-07-26 Thread Jason Wang
This reverts commit 809ecb9bca6a9424ccd392d67e368160f8b76c92. Since it was reported to break vhost_net. We want to cache used event and use it to check for notification. The assumption was that guest won't move the event idx back, but this could happen in fact when 16 bit index wraps around after 6