Re: [PATCH bpf-next 2/7] set_memory: introduce set_memory_[ro|x]_noalias

On Wed, Nov 17, 2021 at 11:57:12PM +0000, Song Liu wrote:

I would agree that __text_poke() is a safer option. But in this case, we 
will need the temporary hole to be 2MB in size. Also, we will probably 
hold the temporary mapping for longer time (the whole JITing process). 
Does this sound reasonable?

No :-)

Jit to a buffer, then copy the buffer into the 2M page using 4k aliases.
IIRC each program is still smaller than a single page, right? So at no
point do you need more than 2 pages mapped anyway.