Re: [patch 3/3] raid5: only wakeup necessary threads

[Tejun Heo]

Hello, Shaohua.

On Tue, Jul 30, 2013 at 09:24:14PM +0800, Shaohua Li wrote:
> In the raid5 case, it's very hard to keep the order the bios passed in, because
> we need read some disks, calculate parity, and write some disks, the timing
> could break any kind of order. Besides the workqueue handles 8 stripes one
> time, so I suppose this keeps some order if there is.

Of course, it can't be absolute but still keeping the relative
ordering and temporal locality (ie. issue IOs in order once the XOR
calculation of the whole source bio is done rather than issuing as
each block completes calculation) would help quite a bit.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/