From: "Wang, Wei W" <wei.w.wang@intel.com>
To: David Hildenbrand <david@redhat.com>, Peter Xu <peterx@redhat.com>
Cc: Hailiang Zhang <zhang.zhanghailiang@huawei.com>,
Juan Quintela <quintela@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Leonardo Bras Soares Passos <lsoaresp@redhat.com>
Subject: RE: [PATCH] migration: Move bitmap_mutex out of migration_bitmap_clear_dirty()
Date: Fri, 2 Jul 2021 02:48:13 +0000 [thread overview]
Message-ID: <604935aa45114d889800f6ccc23c6b13@intel.com> (raw)
In-Reply-To: <304fc749-03a0-b58d-05cc-f0d78350e015@redhat.com>
On Thursday, July 1, 2021 10:22 PM, David Hildenbrand wrote:
> On 01.07.21 14:51, Peter Xu wrote:
> Spoiler alert: the introduction of clean bitmaps partially broke free page hinting
> already (as clearing happens deferred -- and might never happen if we don't
> migrate *any* page within a clean bitmap chunk, so pages actually remain
> dirty ...). "broke" here means that pages still get migrated even though they
> were reported by the guest. We'd actually not want to use clean bmaps with free
> page hinting ... long story short, free page hinting is a very fragile beast already
> and some of the hints are basically ignored and pure overhead ...
Not really. Both clear_bmap and free page hint are to "clear" the bitmap.
No matter who comes first to clear it, it won’t cause more (unexpected) pages to be sent.
Best,
Wei
next prev parent reply other threads:[~2021-07-02 2:49 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-30 20:08 [PATCH] migration: Move bitmap_mutex out of migration_bitmap_clear_dirty() Peter Xu
2021-07-01 4:42 ` Wang, Wei W
2021-07-01 12:51 ` Peter Xu
2021-07-01 14:21 ` David Hildenbrand
2021-07-02 2:48 ` Wang, Wei W [this message]
2021-07-02 7:06 ` David Hildenbrand
2021-07-03 2:53 ` Wang, Wei W
2021-07-05 13:41 ` David Hildenbrand
2021-07-06 9:41 ` Wang, Wei W
2021-07-06 10:05 ` David Hildenbrand
2021-07-06 17:39 ` Peter Xu
2021-07-07 12:45 ` Wang, Wei W
2021-07-07 16:45 ` Peter Xu
2021-07-07 23:25 ` Wang, Wei W
2021-07-08 0:21 ` Peter Xu
2021-07-06 17:47 ` Peter Xu
2021-07-07 8:34 ` Wang, Wei W
2021-07-07 16:54 ` Peter Xu
2021-07-08 2:55 ` Wang, Wei W
2021-07-08 18:10 ` Peter Xu
2021-07-02 2:29 ` Wang, Wei W
2021-07-06 17:59 ` Peter Xu
2021-07-07 8:33 ` Wang, Wei W
2021-07-07 16:44 ` Peter Xu
2021-07-08 2:49 ` Wang, Wei W
2021-07-08 18:30 ` Peter Xu
2021-07-09 8:58 ` Wang, Wei W
2021-07-09 14:48 ` Peter Xu
2021-07-13 8:20 ` Wang, Wei W
2021-07-03 16:31 ` Lukas Straub
2021-07-04 14:14 ` Lukas Straub
2021-07-06 18:37 ` Peter Xu
2021-07-13 8:40 ` Wang, Wei W
2021-07-13 10:22 ` David Hildenbrand
2021-07-14 5:03 ` Wang, Wei W
2021-07-13 15:59 ` Peter Xu
2021-07-14 5:04 ` Wang, Wei W
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