On Thu, 14 Dec 2017 16:17:18 +0100 Michal Hocko <[email protected]> wrote:
> > as fast as possible, SRCU instead of reference count is used to > > implement get/put_swap_device(). From get_swap_device() to > > put_swap_device(), the reader side of SRCU is locked, so > > synchronize_srcu() in swapoff() will wait until put_swap_device() is > > called. > > It is quite unfortunate to pull SRCU as a dependency to the core kernel. > Different attempts to do this have failed in the past. This one is > slightly different though because I would suspect that those tiny > systems do not configure swap. But who knows, maybe they do. > > Anyway, if you are worried about performance then I would expect some > numbers to back that worry. So why don't simply start with simpler > ref count based and then optimize it later based on some actual numbers. > Btw. have you considered pcp refcount framework. I would suspect that > this would give you close to SRCU performance. <squeaky-wheel>Or use stop_kernel() ;)</squeaky-wheel>
