Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Reclamation interactions with RCU

Dan Carpenter
2024-03-20T18:32:59Z

On Tue, Mar 12, 2024 at 03:46:32PM +0100, Vlastimil Babka wrote:
> But if we change it to effectively mean GFP_NOFAIL (for non-costly
> allocations), there should be a manageable number of places to change to a
> variant that allows failure.

What does that even mean if GFP_NOFAIL can fail for "costly" allocations?
I thought GFP_NOFAIL couldn't fail at all...

Unfortunately, it's common that when we can't decide on a sane limit for
something people just say "let the user decide based on how much memory
they have". I have added some integer overflow checks which allow the
user to allocate up to UINT_MAX bytes so I know this code is out
there. We can't just s/GFP_KERNEL/GFP_NOFAIL/.

From a static analysis perspective it would be nice if the callers
explicitly marked which allocations can fail and which can't.

regards,
dan carpenter