Re: [PATCH] mm/vmalloc: Keep a separate lazy-free list

[Andrew Morton]

On Fri, 15 Apr 2016 12:14:31 +0100 Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:

> > > purge_fragmented_blocks() manages per-cpu lists, so that looks safe
> > > under its own rcu_read_lock.
> > >
> > > Yes, it looks feasible to remove the purge_lock if we can relax sync.
> > 
> > what is still left is waiting on vmap_area_lock for !sync mode.
> > but probably is not that bad.
> 
> Ok, that's bit beyond my comfort zone with a patch to change the free
> list handling. I'll chicken out for the time being, atm I am more
> concerned that i915.ko may call set_page_wb() frequently on individual
> pages.

Nick Piggin's vmap rewrite.  20x (or more) faster. 
https://lwn.net/Articles/285341/

10 years ago, never finished.