On Fri, 26 Nov 2021 11:48:46 +0100 Michal Hocko <mhocko@xxxxxxxx> wrote: > 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? Well. Like GFP_NOFAIL, every use is a sin. But I don't think I've ever seen a real-world report of anyone hitting GFP_NOFAIL's theoretical issues. I assume there will be a v3?
