Re: [xfs-masters] [RESEND][PATCH 6/7] xfs: Remove code handling bio_alloc failure with __GFP_WAIT

Dave Chinner
2009-04-20T01:02:50Z

On Wed, Apr 15, 2009 at 04:09:30PM +0530, Nikanth Karthikesan wrote:
> Resending as I accidentally missed Jens earlier.
>
> Jens, can you merge this as well.
>
> Thanks
> Nikanth
>
> Remove code handling bio_alloc failure with __GFP_WAIT.
> GFP_NOIO implies __GFP_WAIT.

Not sure that is right. The intent of the code is that if we can't
get a large bio immediately, try a smaller one which is more likely
to succeed when we are under memory pressure. i.e. we will get IO
moving faster than if we waited for a maximally sized biovec to be
allocated.

IOWs, I don't think __GFP_WAIT is implied by this code, regardless
of what GFP_NOIO actually means now. The same code fragment can be
found in NILFS, and it uses GFP_NOWAIT, not GFP_NOIO. I suspect that
this is what this XFS code should be changed to use to retain the
original intent of the code....

Cheers,

Dave.
--
Dave Chinner
dgc@evostor.com