[dm-devel] Re: [PATCH] raid1: use __GFP_NOFAIL

[Mikulas Patocka]

On Fri, 1 May 2009, Alasdair G Kergon wrote:

> On Mon, Apr 27, 2009 at 07:01:22AM -0400, Mikulas Patocka wrote:
> > This is a bug I found when implementing the barriers. There should be 
> > __GFP_NOFAIL if the code can't handle an allocation failure.
>  
> See also this one:
>   dm-raid1-mempool-bug-workaround-reversion.patch
> 
> Has the original reason for that workaround gone away now or is that
> mempool still being used incorrectly?
> 
> Alasdair

As I said on chat, don't remove that GFP_IO allocation. The code is 
deadlocky anyway and allocation from a mempool with GFP_ATOMIC and, in 
case of failure, allocation from memory with GFP_IO is the best that can 
be done to reduce the probability of the deadlock.

Mikulas