On Fri 30-06-17 12:15:21, Thomas Gleixner wrote: [...] > Sure. Just to make you to mull over more stuff, find below the patch which > moves all of this to use the cpuhotplug lock. > > Thanks, > > tglx > > 8<-------------------- > Subject: mm/memory-hotplug: Use cpu hotplug lock > From: Thomas Gleixner <t...@linutronix.de> > Date: Thu, 29 Jun 2017 16:30:00 +0200 > > Most place which take the memory hotplug lock take the cpu hotplug lock as > well. Avoid the double locking and use the cpu hotplug lock for both.
Hmm, I am usually not a fan of locks conflating because it is then less clear what the lock actually protects. Memory and cpu hotplugs should be largely independent so I am not sure this patch simplify things a lot. It is nice to see few lines go away but I am little bit worried that we will enventually develop a separate locking again in future for some weird memory hotplug usecases. > Not-Yet-Signed-off-by: Thomas Gleixner <t...@linutronix.de> [...] > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c [...] > @@ -2138,7 +2114,7 @@ void __ref remove_memory(int nid, u64 st > > try_offline_node(nid); > > - mem_hotplug_done(); > + cpus_write_lock(); unlock you meant here, right? -- Michal Hocko SUSE Labs
