Re: [PATCH 1/2] bcachefs: do not use PF_MEMALLOC_NORECLAIM

[Kent Overstreet]

On Mon, Aug 26, 2024 at 08:41:42PM GMT, Matthew Wilcox wrote:
> On Mon, Aug 26, 2024 at 03:39:47PM -0400, Kent Overstreet wrote:
> > Given the amount of plumbing required here, it's clear that passing gfp
> > flags is the less safe way of doing it, and this really does belong in
> > the allocation context.
> > 
> > Failure to pass gfp flags correctly (which we know is something that
> > happens today, e.g. vmalloc -> pte allocation) means you're introducing
> > a deadlock.
> 
> The problem with vmalloc is that the page table allocation _doesn't_
> take a GFP parameter.

and given the increasing usage of kvmalloc() this is something we really
should be thinking about