Re: [PATCH v2 2/4] mm/vmalloc: add support for __GFP_NOFAIL

[Michal Hocko]

On Mon 22-11-21 16:32:31, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
> 
> Dave Chinner has mentioned that some of the xfs code would benefit from
> kvmalloc support for __GFP_NOFAIL because they have allocations that
> cannot fail and they do not fit into a single page.
> 
> The large part of the vmalloc implementation already complies with the
> given gfp flags so there is no work for those to be done. The area
> and page table allocations are an exception to that. Implement a retry
> loop for those.
> 
> Add a short sleep before retrying. 1 jiffy is a completely random
> timeout. Ideally the retry would wait for an explicit event - e.g.
> a change to the vmalloc space change if the failure was caused by
> the space fragmentation or depletion. But there are multiple different
> reasons to retry and this could become much more complex. Keep the retry
> simple for now and just sleep to prevent from hogging CPUs.
> 
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>

Are there still any concerns around this patch or the approach in
general?
-- 
Michal Hocko
SUSE Labs