Re: [Qemu-devel] [PATCH] migration: Fix multi-thread compression bug

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, May 03, 2016 at 02:38:41PM +0800, Liang Li wrote:
> Recently, a bug related to multiple thread compression feature for
> live migration is reported. The destination side will be blocked
> during live migration if there are heavy workload in host and
> memory intensive workload in guest, this is most likely to happen
> when there is one decompression thread.
> 
> Some parts of the decompression code are incorrect:
> 1. The main thread receives data from source side will enter a busy
> loop to wait for a free decompression thread.
> 2. A lock is needed to protect the decomp_param[idx]->start, because
> it is checked in the main thread and is updated in the decompression
> thread.
> 
> Fix these two issues by following the code pattern for compression.
> 
> Reported-by: Daniel P. Berrange <berrange@redhat.com>
> Signed-off-by: Liang Li <liang.z.li@intel.com>
> ---
>  migration/ram.c | 38 +++++++++++++++++++++++++++-----------
>  1 file changed, 27 insertions(+), 11 deletions(-)

Tested-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>


Regards,
Daniel
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