From: "Michael S. Tsirkin" <mst@redhat.com>
To: "Wang, Wei W" <wei.w.wang@intel.com>
Cc: "virtio-dev@lists.oasis-open.org"
<virtio-dev@lists.oasis-open.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"mhocko@kernel.org" <mhocko@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"liliang.opensource@gmail.com" <liliang.opensource@gmail.com>,
"yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.com>,
"quan.xu0@gmail.com" <quan.xu0@gmail.com>,
"nilal@redhat.com" <nilal@redhat.com>,
"riel@redhat.com" <riel@redhat.com>,
"huangzhichao@huawei.com" <huangzhichao@huawei.com>
Subject: [virtio-dev] Re: [PATCH v30 2/4] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
Date: Thu, 5 Apr 2018 17:03:40 +0300 [thread overview]
Message-ID: <20180405170248-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <286AC319A985734F985F78AFA26841F7394A7F3B@shsmsx102.ccr.corp.intel.com>
On Thu, Apr 05, 2018 at 02:05:03AM +0000, Wang, Wei W wrote:
> On Thursday, April 5, 2018 9:12 AM, Michael S. Tsirkin wrote:
> > On Thu, Apr 05, 2018 at 12:30:27AM +0000, Wang, Wei W wrote:
> > > On Wednesday, April 4, 2018 10:08 PM, Michael S. Tsirkin wrote:
> > > > On Wed, Apr 04, 2018 at 10:07:51AM +0800, Wei Wang wrote:
> > > > > On 04/04/2018 02:47 AM, Michael S. Tsirkin wrote:
> > > > > > On Wed, Apr 04, 2018 at 12:10:03AM +0800, Wei Wang wrote:
> > > I'm afraid the driver couldn't be aware if the added hints are stale
> > > or not,
> >
> >
> > No - I mean that driver has code that compares two values and stops
> > reporting. Can one of the values be stale?
>
> The driver compares "vb->cmd_id_use != vb->cmd_id_received" to decide if it needs to stop reporting hints, and cmd_id_received is what the driver reads from host (host notifies the driver to read for the latest value). If host sends a new cmd id, it will notify the guest to read again. I'm not sure how that could be a stale cmd id (or maybe I misunderstood your point here?)
>
> Best,
> Wei
The comparison is done in one thread, the update in another one.
--
MST
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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: "Wang, Wei W" <wei.w.wang@intel.com>
Cc: "virtio-dev@lists.oasis-open.org"
<virtio-dev@lists.oasis-open.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"mhocko@kernel.org" <mhocko@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"liliang.opensource@gmail.com" <liliang.opensource@gmail.com>,
"yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.com>,
"quan.xu0@gmail.com" <quan.xu0@gmail.com>,
"nilal@redhat.com" <nilal@redhat.com>,
"riel@redhat.com" <riel@redhat.com>,
"huangzhichao@huawei.com" <huangzhichao@huawei.com>
Subject: Re: [PATCH v30 2/4] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
Date: Thu, 5 Apr 2018 17:03:40 +0300 [thread overview]
Message-ID: <20180405170248-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <286AC319A985734F985F78AFA26841F7394A7F3B@shsmsx102.ccr.corp.intel.com>
On Thu, Apr 05, 2018 at 02:05:03AM +0000, Wang, Wei W wrote:
> On Thursday, April 5, 2018 9:12 AM, Michael S. Tsirkin wrote:
> > On Thu, Apr 05, 2018 at 12:30:27AM +0000, Wang, Wei W wrote:
> > > On Wednesday, April 4, 2018 10:08 PM, Michael S. Tsirkin wrote:
> > > > On Wed, Apr 04, 2018 at 10:07:51AM +0800, Wei Wang wrote:
> > > > > On 04/04/2018 02:47 AM, Michael S. Tsirkin wrote:
> > > > > > On Wed, Apr 04, 2018 at 12:10:03AM +0800, Wei Wang wrote:
> > > I'm afraid the driver couldn't be aware if the added hints are stale
> > > or not,
> >
> >
> > No - I mean that driver has code that compares two values and stops
> > reporting. Can one of the values be stale?
>
> The driver compares "vb->cmd_id_use != vb->cmd_id_received" to decide if it needs to stop reporting hints, and cmd_id_received is what the driver reads from host (host notifies the driver to read for the latest value). If host sends a new cmd id, it will notify the guest to read again. I'm not sure how that could be a stale cmd id (or maybe I misunderstood your point here?)
>
> Best,
> Wei
The comparison is done in one thread, the update in another one.
--
MST
next prev parent reply other threads:[~2018-04-05 14:03 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-03 16:10 [virtio-dev] [PATCH v30 0/4] Virtio-balloon: support free page reporting Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` [PATCH v30 1/4] mm: support reporting free page blocks Wei Wang
2018-04-03 16:10 ` [virtio-dev] " Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` [virtio-dev] [PATCH v30 2/4] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 18:47 ` [virtio-dev] " Michael S. Tsirkin
2018-04-03 18:47 ` Michael S. Tsirkin
2018-04-04 2:07 ` [virtio-dev] " Wei Wang
2018-04-04 2:07 ` Wei Wang
2018-04-04 14:07 ` [virtio-dev] " Michael S. Tsirkin
2018-04-04 14:07 ` Michael S. Tsirkin
2018-04-04 14:07 ` Michael S. Tsirkin
2018-04-05 0:30 ` Wang, Wei W
2018-04-05 0:30 ` [virtio-dev] " Wang, Wei W
2018-04-05 0:30 ` Wang, Wei W
2018-04-05 1:12 ` [virtio-dev] " Michael S. Tsirkin
2018-04-05 1:12 ` Michael S. Tsirkin
2018-04-05 2:05 ` Wang, Wei W
2018-04-05 2:05 ` [virtio-dev] " Wang, Wei W
2018-04-05 2:05 ` Wang, Wei W
2018-04-05 14:03 ` Michael S. Tsirkin
2018-04-05 14:03 ` Michael S. Tsirkin [this message]
2018-04-05 14:03 ` Michael S. Tsirkin
2018-04-05 15:47 ` Wang, Wei W
2018-04-05 15:47 ` [virtio-dev] " Wang, Wei W
2018-04-05 15:47 ` Wang, Wei W
2018-04-05 18:30 ` [virtio-dev] " Michael S. Tsirkin
2018-04-05 18:30 ` Michael S. Tsirkin
2018-04-06 0:11 ` [virtio-dev] " Wang, Wei W
2018-04-06 0:11 ` Wang, Wei W
2018-04-06 0:11 ` Wang, Wei W
2018-04-05 18:30 ` Michael S. Tsirkin
2018-04-05 1:12 ` Michael S. Tsirkin
2018-04-04 2:07 ` Wei Wang
2018-04-03 18:47 ` Michael S. Tsirkin
2018-04-03 16:10 ` [virtio-dev] [PATCH v30 3/4] mm/page_poison: expose page_poisoning_enabled to kernel modules Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` [virtio-dev] [PATCH v30 4/4] virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON Wei Wang
2018-04-03 16:10 ` Wei Wang
2018-04-03 16:10 ` Wei Wang
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