On Wed 07-11-18 11:28:37, Michal Hocko wrote: > On Wed 07-11-18 09:50:10, Vlastimil Babka wrote: > > On 11/7/18 8:02 AM, Konstantin Khlebnikov wrote: > [...] > > > Could you point what exactly are you fixing with this set? > > > > > > from v2: > > > > > > > totalram_pages, zone->managed_pages and totalhigh_pages updates > > > > are protected by managed_page_count_lock, but readers never care > > > > about it. Convert these variables to atomic to avoid readers > > > > potentially seeing a store tear. > > > > > > This? > > > > > > > > > Aligned unsigned long almost always stored at once. > > > > The point is "almost always", so better not rely on it :) But the main > > motivation was that managed_page_count_lock handling was complicating > > Arun's "memory_hotplug: Free pages as higher order" patch and it seemed > > a better idea to just remove and convert this to atomics, with > > preventing potential store-to-read tearing as a bonus. > > And more importantly the lock itself seems bogus as mentioned here > http://lkml.kernel.org/r/20181106141732.GR27423@xxxxxxxxxxxxxx Should be http://lkml.kernel.org/r/20181107103630.GF2453@xxxxxxxxxxxxxx -- Michal Hocko SUSE Labs
