Re: [patch]blk-mq: blk_mq_tag_to_rq should handle flush request

From: Jens Axboe
Date: Wed Jun 04 2014 - 11:20:06 EST

On 2014-06-04 09:16, Christoph Hellwig wrote:
On Wed, Jun 04, 2014 at 09:11:47AM -0600, Jens Axboe wrote:
On 2014-06-04 09:10, Christoph Hellwig wrote:
On Wed, Jun 04, 2014 at 09:08:12AM -0600, Jens Axboe wrote:
The performance regression is caused by "blk-mq: avoid code
duplication", but I don't really understand why yet.

Gah, looks like this one dropped the tag idling. I bet that is why.

Ah, thanks. It's indeed exactly the same sort of slow down I bisected
back then, this should have rung a bell instead of keeping me occupied
for hours..

Patch is committed :-)

Oh well, I had just prepared the same one for you, but I want to at
least do basic sanity checking of my rebased tree with the fixes applied
now that I'm done bisecting.

Please do. If there's anything else I need, let me know. It wasn't clear to me if the cdb patch was in blk-mq or scsi-mq. I'll flush my queue out this afternoon, so that -rc1 will hopefully have everything in a sane state.

Jens Axboe

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at