Re: [dm-devel] [PATCH 2/2] block: Avoid deadlocks with bio allocation by stacking drivers

[Alasdair G Kergon <agk redhat com>]

On Mon, Sep 10, 2012 at 04:35:02PM -0700, Tejun Heo wrote:
> debug.  Would it be difficult to convert dm drivers to collect size
> requirements and use front-pad for all per-bio data?
 
I can't give a quick answer because a single bio may require a variable
number (depending on the bio content) of (sequential) mempool_allocs from the
same mempool to complete its processing, so we do have to audit all this very
carefully to see what can/can't be pulled out.

Alasdair