Re: Re: [PATCH 1/2 V1] [PATCH] fs/block-dev.c:fix performance regression in O_DIRECT writes to md block devices

[majianpeng <majianpeng@gmail.com>]

On 2012-07-17 11:04 NeilBrown <neilb@suse.de> Wrote:
>On Mon, 16 Jul 2012 14:22:03 +0800 majianpeng <majianpeng@gmail.com> wrote:
>
>> For regular file, write operaion used blk_plug function.But for block
>> file,write operation did not use blk_plug.
>> This patch is also for write-cache mode for block-device.
>> 
>> Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
>
>Reviewed-by: NeilBrown <neilb@suse.de>
>
>Will you take this Jens?  Though mail to you seem to be bouncing:
>
><axboe@fusionio.com>: host mail.fusionio.com[10.101.1.19] said: 554 5.4.6 Hop
>    count exceeded - possible mail loop (in reply to end of DATA command)
>
>so I'm not sure you'll even see this :-(
>
>NeilBrown
>
>> ---
>>  fs/block_dev.c |    3 +++
>>  1 files changed, 3 insertions(+), 0 deletions(-)
>> 
>> diff --git a/fs/block_dev.c b/fs/block_dev.c
>> index c2bbe1f..cf10778 100644
>> --- a/fs/block_dev.c
>> +++ b/fs/block_dev.c
>> @@ -1579,9 +1579,11 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
>>  {
>>  	struct file *file = iocb->ki_filp;
>>  	ssize_t ret;
>> +	struct blk_plug plug;
>>  
>>  	BUG_ON(iocb->ki_pos != pos);
>>  
>> +	blk_start_plug(&plug);
>>  	ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
>>  	if (ret > 0 || ret == -EIOCBQUEUED) {
>>  		ssize_t err;
>> @@ -1590,6 +1592,7 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
>>  		if (err < 0 && ret > 0)
>>  			ret = err;
>>  	}
>> +	blk_finish_plug(&plug);
>>  	return ret;
>>  }
>>  EXPORT_SYMBOL_GPL(blkdev_aio_write);
>
>

How about this patch? apply or reject? Thanks!