On Thu, Sep 05, 2024 at 10:05:15AM -0400, Kent Overstreet wrote: > > That may be the currrent state of affiars; but is it > > ****guaranteed**** forever and ever, amen, that GFP_KERNEL will never > > fail if the amount of memory allocated was lower than a particular > > multiple of the page size? If so, what is that size? I've checked, > > and this is not documented in the formal interface. > > Yeah, and I think we really need to make that happen, in order to head > off a lot more sillyness in the future. I don't think there's any "sillyness"; I hear that you believe that it's silly, but I think what we have is totally fine. I've done a quick check of ext4, and we do check the error returns in most if not all of the calls where we pass in __GFP_NOFAIL and/or are small allocations less than the block size. We won't crash if someone sends a patch which violates the documented guarantee of __GFP_NOFAIL. So what's the sillynesss? In any case, Michal has said ix-nay on making GFP_KERNEL == GFP_NOFAIL for small allocations as documented guarantee, as opposed to the way things work today, so as far as I'm concerned, the matter is closed. - Ted
