From: Wei Wang <wei.w.wang@intel.com>
To: Peter Xu <peterx@redhat.com>
Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org,
mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com,
pbonzini@redhat.com, liliang.opensource@gmail.com,
nilal@redhat.com, riel@redhat.com
Subject: Re: [virtio-dev] Re: [PATCH v9 3/8] migration: use bitmap_mutex in migration_bitmap_clear_dirty
Date: Tue, 27 Nov 2018 18:17:13 +0800 [thread overview]
Message-ID: <5BFD19A9.2010000@intel.com> (raw)
In-Reply-To: <20181127074127.GD3205@xz-x1>
On 11/27/2018 03:41 PM, Peter Xu wrote:
>
> Ok then I'm fine with it. Though you could update the comments too if
> you like:
>
> /* protects modification of the bitmap and migration_dirty_pages */
> QemuMutex bitmap_mutex;
>
> And it's tricky that sometimes we don't take the lock when reading
> this variable "migration_dirty_pages". I don't see obvious issue so
> far, hope it's true (at least I skipped the colo ones...).
The caller reads the value just to estimate the remaining_size, and
it seems fine without a lock, because whether it reads a
value before the update or after the update seem not causing
an issue.
Best,
Wei
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WARNING: multiple messages have this Message-ID (diff)
From: Wei Wang <wei.w.wang@intel.com>
To: Peter Xu <peterx@redhat.com>
Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org,
mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com,
pbonzini@redhat.com, liliang.opensource@gmail.com,
nilal@redhat.com, riel@redhat.com
Subject: Re: [Qemu-devel] [virtio-dev] Re: [PATCH v9 3/8] migration: use bitmap_mutex in migration_bitmap_clear_dirty
Date: Tue, 27 Nov 2018 18:17:13 +0800 [thread overview]
Message-ID: <5BFD19A9.2010000@intel.com> (raw)
In-Reply-To: <20181127074127.GD3205@xz-x1>
On 11/27/2018 03:41 PM, Peter Xu wrote:
>
> Ok then I'm fine with it. Though you could update the comments too if
> you like:
>
> /* protects modification of the bitmap and migration_dirty_pages */
> QemuMutex bitmap_mutex;
>
> And it's tricky that sometimes we don't take the lock when reading
> this variable "migration_dirty_pages". I don't see obvious issue so
> far, hope it's true (at least I skipped the colo ones...).
The caller reads the value just to estimate the remaining_size, and
it seems fine without a lock, because whether it reads a
value before the update or after the update seem not causing
an issue.
Best,
Wei
next prev parent reply other threads:[~2018-11-27 10:12 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-15 10:07 [virtio-dev] [PATCH v9 0/8] virtio-balloon: free page hint support Wei Wang
2018-11-15 10:07 ` [Qemu-devel] " Wei Wang
2018-11-15 10:07 ` [virtio-dev] [PATCH v9 1/8] bitmap: fix bitmap_count_one Wei Wang
2018-11-15 10:07 ` [Qemu-devel] " Wei Wang
2018-11-15 10:07 ` [virtio-dev] [PATCH v9 2/8] bitmap: bitmap_count_one_with_offset Wei Wang
2018-11-15 10:07 ` [Qemu-devel] " Wei Wang
2018-11-15 10:07 ` [virtio-dev] [PATCH v9 3/8] migration: use bitmap_mutex in migration_bitmap_clear_dirty Wei Wang
2018-11-15 10:07 ` [Qemu-devel] " Wei Wang
2018-11-27 5:40 ` Peter Xu
2018-11-27 6:02 ` [virtio-dev] " Wei Wang
2018-11-27 6:02 ` [Qemu-devel] " Wei Wang
2018-11-27 6:12 ` [virtio-dev] " Wei Wang
2018-11-27 6:12 ` [Qemu-devel] " Wei Wang
2018-11-27 7:41 ` Peter Xu
2018-11-27 10:17 ` Wei Wang [this message]
2018-11-27 10:17 ` Wei Wang
2018-11-15 10:08 ` [virtio-dev] [PATCH v9 4/8] migration: API to clear bits of guest free pages from the dirty bitmap Wei Wang
2018-11-15 10:08 ` [Qemu-devel] " Wei Wang
2018-11-27 6:06 ` Peter Xu
2018-11-27 6:52 ` [virtio-dev] " Wei Wang
2018-11-27 6:52 ` [Qemu-devel] " Wei Wang
2018-11-27 7:43 ` Peter Xu
2018-11-15 10:08 ` [virtio-dev] [PATCH v9 5/8] migration/ram.c: add a notifier chain for precopy Wei Wang
2018-11-15 10:08 ` [Qemu-devel] " Wei Wang
2018-11-27 7:38 ` Peter Xu
2018-11-27 10:25 ` [virtio-dev] " Wei Wang
2018-11-27 10:25 ` [Qemu-devel] " Wei Wang
2018-11-28 5:26 ` Peter Xu
2018-11-28 9:01 ` [virtio-dev] " Wei Wang
2018-11-28 9:01 ` [Qemu-devel] " Wei Wang
2018-11-28 9:32 ` Peter Xu
2018-11-29 3:40 ` [virtio-dev] " Wei Wang
2018-11-29 3:40 ` [Qemu-devel] " Wei Wang
2018-11-29 5:10 ` Peter Xu
2018-11-29 5:47 ` Peter Xu
2018-11-29 6:30 ` [virtio-dev] " Wei Wang
2018-11-29 6:30 ` [Qemu-devel] " Wei Wang
2018-11-30 5:05 ` [virtio-dev] " Wei Wang
2018-11-30 5:05 ` [Qemu-devel] " Wei Wang
2018-11-30 5:57 ` Peter Xu
2018-11-30 7:09 ` [virtio-dev] " Wei Wang
2018-11-30 7:09 ` [Qemu-devel] " Wei Wang
2018-11-15 10:08 ` [virtio-dev] [PATCH v9 6/8] migration/ram.c: add a function to disable the bulk stage Wei Wang
2018-11-15 10:08 ` [Qemu-devel] " Wei Wang
2018-11-15 10:08 ` [virtio-dev] [PATCH v9 7/8] migration: move migrate_postcopy() to include/migration/misc.h Wei Wang
2018-11-15 10:08 ` [Qemu-devel] " Wei Wang
2018-11-15 10:08 ` [virtio-dev] [PATCH v9 8/8] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Wei Wang
2018-11-15 10:08 ` [Qemu-devel] " Wei Wang
2018-11-15 18:50 ` [Qemu-devel] [PATCH v9 0/8] virtio-balloon: free page hint support no-reply
2018-11-16 1:38 ` [virtio-dev] " Wei Wang
2018-11-16 1:38 ` Wei Wang
2018-11-27 3:11 ` [virtio-dev] " Wei Wang
2018-11-27 3:11 ` [Qemu-devel] " Wei Wang
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