Re: [patch 6/12] hold atomic kmaps across generic_file_read

[Jamie Lokier]

Linus Torvalds wrote:
> For people like that, wouldn't it be nice to just be able to tell them: if 
> you do X, we guarantee that you'll get optimal zero-copy performance for 
> reading a file.

Don't forget to include the need for mmap(... MAP_ANON ...) prior to the
read.

Given the user will need to establish a new mapping anyway, why pussy
foot around with subtleties?  Just add a MAP_PREFAULT flag to mmap(),
which reads the whole file and maps it before returning.

-- Jamie