Re: [Qemu-devel] [PATCH] migrate.c: migrate_fd_put_buffer: Do not busyloop: stop writing if EWOULDBLOCK

[Anthony Liguori <aliguori@us.ibm.com>]

Dor Laor wrote:
> Uri Lublin wrote:
>> The migration code is non-blocking, designed for live migration.
>>
>> Practically migrate_fd_put_buffer busy-loops trying to write, as
>> on many machines EWOULDBLOCK==EAGAIN (look in 
>> include/asm-generic/errno.h).
>>
>> Signed-off-by: Uri Lublin <uril@redhat.com>
>> ---
>>  migration.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/migration.c b/migration.c
>> index 859d945..ca397fa 100644
>> --- a/migration.c
>> +++ b/migration.c
>> @@ -176,7 +176,7 @@ ssize_t migrate_fd_put_buffer(void *opaque, const 
>> void *data, size_t size)
>>  
>>      do {
>>          ret = s->write(s, data, size);
>> -    } while (ret == -1 && ((s->get_error(s)) == EINTR || 
>> (s->get_error(s)) == EWOULDBLOCK));
>> +    } while (ret == -1 && ((s->get_error(s)) == EINTR));
>>  
>>      if (ret == -1)
>>          ret = -(s->get_error(s));
>>   
> There is additional stuff that needs to test EWOULDBLOCK in further 
> locations in the code.
> Otherwise migration will fail.
>
> commit 2d875410cb168fa728dcde96885a3e4ddfd0bb58
> Author: Dor Laor <dor@redhat.com>
> Date:   Thu May 21 12:29:39 2009 +0300
>
>    The migration code is non-blocking, designed for live migration.
>      Practically migrate_fd_put_buffer busy-loops trying to write, as
>    on many machines EWOULDBLOCK==EAGAIN (look in 
> include/asm-generic/errno.h).
>      Based on Uri Lublin's patch.
>    Signed-off-by: Dor Laor <dor@redhat.com>

This is whitespace damaged, presumably from copy/paste, can you resend?

-- 
Regards,

Anthony Liguori