From: David Hildenbrand <david@redhat.com>
To: "Wang, Wei W" <wei.w.wang@intel.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Cc: Nadav Amit <namit@vmware.com>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Tyler Sanderson <tysand@google.com>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
David Rientjes <rientjes@google.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: Balloon pressuring page cache
Date: Wed, 5 Feb 2020 10:58:14 +0100 [thread overview]
Message-ID: <ef1dfd46-49c8-8aa9-2a5e-d2ebb2e093f5@redhat.com> (raw)
In-Reply-To: <286AC319A985734F985F78AFA26841F73E41F562@shsmsx102.ccr.corp.intel.com>
On 05.02.20 10:49, Wang, Wei W wrote:
> On Wednesday, February 5, 2020 5:37 PM, David Hildenbrand wrote:
>>>
>>> Not sure how TCG tracks the dirty bits. But In whatever
>>> implementation, the hypervisor should have
>>
>> There is only a single bitmap for that purpose. (well, the one where KVM
>> syncs to)
>>
>>> already dealt with the race between he current round and the previous
>> round dirty recording.
>>> (the race isn't brought by this feature essentially)
>>
>> It is guaranteed to work reliably without this feature as you only clear what
>> *has been migrated*,
>
> Not "clear what has been migrated" (that skips nothing..)
> Anyway, it's a hint used for optimization.
Yes, an optimization that might easily lead to data corruption when the
two bitmaps are either not in place or don't play along in that specific
way (and I suspect this is the case under TCG).
--
Thanks,
David / dhildenb
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: "Wang, Wei W" <wei.w.wang@intel.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Cc: "virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
Tyler Sanderson <tysand@google.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Nadav Amit <namit@vmware.com>,
David Rientjes <rientjes@google.com>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: Balloon pressuring page cache
Date: Wed, 5 Feb 2020 10:58:14 +0100 [thread overview]
Message-ID: <ef1dfd46-49c8-8aa9-2a5e-d2ebb2e093f5@redhat.com> (raw)
In-Reply-To: <286AC319A985734F985F78AFA26841F73E41F562@shsmsx102.ccr.corp.intel.com>
On 05.02.20 10:49, Wang, Wei W wrote:
> On Wednesday, February 5, 2020 5:37 PM, David Hildenbrand wrote:
>>>
>>> Not sure how TCG tracks the dirty bits. But In whatever
>>> implementation, the hypervisor should have
>>
>> There is only a single bitmap for that purpose. (well, the one where KVM
>> syncs to)
>>
>>> already dealt with the race between he current round and the previous
>> round dirty recording.
>>> (the race isn't brought by this feature essentially)
>>
>> It is guaranteed to work reliably without this feature as you only clear what
>> *has been migrated*,
>
> Not "clear what has been migrated" (that skips nothing..)
> Anyway, it's a hint used for optimization.
Yes, an optimization that might easily lead to data corruption when the
two bitmaps are either not in place or don't play along in that specific
way (and I suspect this is the case under TCG).
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-02-05 9:58 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 0:22 Balloon pressuring page cache Tyler Sanderson via Virtualization
2020-01-29 10:31 ` David Hildenbrand
2020-01-29 19:11 ` Tyler Sanderson via Virtualization
2020-01-30 15:02 ` David Hildenbrand
2020-01-30 15:02 ` David Hildenbrand
2020-01-30 15:20 ` Michael S. Tsirkin
2020-01-30 15:20 ` Michael S. Tsirkin
2020-01-30 15:23 ` David Hildenbrand
2020-01-30 15:23 ` David Hildenbrand
2020-01-30 15:31 ` Wang, Wei W
2020-01-30 15:31 ` Wang, Wei W
2020-01-30 19:59 ` Tyler Sanderson
2020-01-30 19:59 ` Tyler Sanderson via Virtualization
2020-02-03 13:11 ` Michael S. Tsirkin
2020-02-03 13:11 ` Michael S. Tsirkin
2020-02-03 16:18 ` Alexander Duyck
2020-02-03 16:34 ` David Hildenbrand
2020-02-03 16:34 ` David Hildenbrand
2020-02-03 17:03 ` Michael S. Tsirkin
2020-02-03 17:03 ` Michael S. Tsirkin
2020-02-03 20:32 ` Tyler Sanderson
2020-02-03 20:32 ` Tyler Sanderson via Virtualization
2020-02-03 21:22 ` Alexander Duyck
2020-02-03 23:16 ` Tyler Sanderson
2020-02-03 23:16 ` Tyler Sanderson via Virtualization
2020-02-04 0:10 ` Alexander Duyck
2020-02-04 5:45 ` Michael S. Tsirkin
2020-02-04 5:45 ` Michael S. Tsirkin
2020-02-04 8:29 ` David Hildenbrand
2020-02-04 8:29 ` David Hildenbrand
2020-02-04 18:52 ` Tyler Sanderson
2020-02-04 18:52 ` Tyler Sanderson via Virtualization
2020-02-04 18:56 ` Michael S. Tsirkin
2020-02-04 18:56 ` Michael S. Tsirkin
2020-02-04 19:17 ` David Hildenbrand
2020-02-04 19:17 ` David Hildenbrand
2020-02-04 23:58 ` Tyler Sanderson
2020-02-04 23:58 ` Tyler Sanderson via Virtualization
2020-02-05 0:15 ` Tyler Sanderson
2020-02-05 0:15 ` Tyler Sanderson via Virtualization
2020-02-05 6:57 ` Michael S. Tsirkin
2020-02-05 6:57 ` Michael S. Tsirkin
2020-02-05 19:01 ` Tyler Sanderson
2020-02-05 19:01 ` Tyler Sanderson via Virtualization
2020-02-05 19:22 ` Alexander Duyck
2020-02-05 21:44 ` Tyler Sanderson
2020-02-05 21:44 ` Tyler Sanderson via Virtualization
2020-02-06 11:00 ` David Hildenbrand
2020-02-06 11:00 ` David Hildenbrand
2020-02-03 22:50 ` Nadav Amit
2020-02-03 22:50 ` Nadav Amit via Virtualization
2020-02-04 8:35 ` David Hildenbrand
2020-02-04 8:35 ` David Hildenbrand
2020-02-04 8:40 ` Michael S. Tsirkin
2020-02-04 8:40 ` Michael S. Tsirkin
2020-02-04 8:48 ` David Hildenbrand
2020-02-04 8:48 ` David Hildenbrand
2020-02-04 14:30 ` David Hildenbrand
2020-02-04 14:30 ` David Hildenbrand
2020-02-04 16:50 ` Michael S. Tsirkin
2020-02-04 16:50 ` Michael S. Tsirkin
2020-02-04 16:56 ` David Hildenbrand
2020-02-04 16:56 ` David Hildenbrand
2020-02-04 20:33 ` Michael S. Tsirkin
2020-02-04 20:33 ` [virtio-dev] " Michael S. Tsirkin
2020-02-04 20:33 ` Michael S. Tsirkin
2020-02-05 8:31 ` David Hildenbrand
2020-02-05 8:31 ` [virtio-dev] " David Hildenbrand
2020-02-05 6:52 ` Wang, Wei W
2020-02-05 6:52 ` Wang, Wei W
2020-02-05 7:05 ` Michael S. Tsirkin
2020-02-05 7:05 ` Michael S. Tsirkin
2020-02-05 8:50 ` Wang, Wei W
2020-02-05 8:50 ` Wang, Wei W
2020-02-05 6:49 ` Wang, Wei W
2020-02-05 6:49 ` Wang, Wei W
2020-02-05 8:19 ` David Hildenbrand
2020-02-05 8:19 ` David Hildenbrand
2020-02-05 8:54 ` Wang, Wei W
2020-02-05 8:54 ` Wang, Wei W
2020-02-05 8:56 ` David Hildenbrand
2020-02-05 8:56 ` David Hildenbrand
2020-02-05 9:00 ` Wang, Wei W
2020-02-05 9:00 ` Wang, Wei W
2020-02-05 9:05 ` David Hildenbrand
2020-02-05 9:05 ` David Hildenbrand
2020-02-05 9:19 ` Wang, Wei W
2020-02-05 9:19 ` Wang, Wei W
2020-02-05 9:22 ` David Hildenbrand
2020-02-05 9:22 ` David Hildenbrand
2020-02-05 9:35 ` Wang, Wei W
2020-02-05 9:35 ` Wang, Wei W
2020-02-05 9:37 ` David Hildenbrand
2020-02-05 9:37 ` David Hildenbrand
2020-02-05 9:49 ` Wang, Wei W
2020-02-05 9:49 ` Wang, Wei W
2020-02-05 9:58 ` David Hildenbrand [this message]
2020-02-05 9:58 ` David Hildenbrand
2020-02-05 10:25 ` Michael S. Tsirkin
2020-02-05 10:25 ` Michael S. Tsirkin
2020-02-05 10:42 ` David Hildenbrand
2020-02-05 10:42 ` David Hildenbrand
2020-02-05 9:35 ` Michael S. Tsirkin
2020-02-05 9:35 ` Michael S. Tsirkin
2020-02-05 18:43 ` Tyler Sanderson
2020-02-05 18:43 ` Tyler Sanderson via Virtualization
2020-02-06 9:30 ` Wang, Wei W
2020-02-06 9:30 ` Wang, Wei W
2020-02-05 7:35 ` Nadav Amit
2020-02-05 7:35 ` Nadav Amit via Virtualization
2020-02-05 8:19 ` David Hildenbrand
2020-02-05 8:19 ` David Hildenbrand
2020-02-05 10:27 ` Michael S. Tsirkin
2020-02-05 10:27 ` Michael S. Tsirkin
2020-02-05 10:43 ` David Hildenbrand
2020-02-05 10:43 ` David Hildenbrand
2020-01-30 22:46 ` Tyler Sanderson
2020-01-30 22:46 ` Tyler Sanderson via Virtualization
2020-02-02 0:21 ` David Rientjes via Virtualization
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