Re: [PATCH 1/2 v2] bcachefs: do not use PF_MEMALLOC_NORECLAIM
From: Dave Chinner <david@fromorbit.com>
Date: 2024-08-28 04:10:01
Also in:
linux-bcachefs, linux-fsdevel, linux-mm, lkml
On Tue, Aug 27, 2024 at 08:15:43AM +0200, Michal Hocko wrote:
From: Michal Hocko <mhocko@suse.com> bch2_new_inode relies on PF_MEMALLOC_NORECLAIM to try to allocate a new inode to achieve GFP_NOWAIT semantic while holding locks. If this allocation fails it will drop locks and use GFP_NOFS allocation context. We would like to drop PF_MEMALLOC_NORECLAIM because it is really dangerous to use if the caller doesn't control the full call chain with this flag set. E.g. if any of the function down the chain needed GFP_NOFAIL request the PF_MEMALLOC_NORECLAIM would override this and cause unexpected failure. While this is not the case in this particular case using the scoped gfp semantic is not really needed bacause we can easily pus the allocation context down the chain without too much clutter. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Michal Hocko <mhocko@suse.com>
Looks good to me. Reviewed-by: Dave Chinner <redacted> -- Dave Chinner david@fromorbit.com