Re: [PATCH] mm: page_alloc: document kmemleak's non-blockable __GFP_NOFAIL case

[Yang Shi]

On 7/13/19 2:25 PM, Matthew Wilcox wrote:
> On Sat, Jul 13, 2019 at 04:49:04AM +0800, Yang Shi wrote:
> > When running ltp's oom test with kmemleak enabled, the below warning was
> > triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
> > passed in:
> There are lots of places where kmemleak will call kmalloc with
> __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM (including the XArray code, which
> is how I know about it).  It needs to be fixed to allow its internal
> allocations to fail and return failure of the original allocation as
> a consequence.

Do you mean kmemleak internal allocation? It would fail even though 
__GFP_NOFAIL is passed in if GFP_NOWAIT is specified. Currently buddy 
allocator will not retry if the allocation is non-blockable.