Re: [PATCH v2 0/5] Allocate memmap from hotadded memory

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, 2019-07-29 at 10:06 +0200, David Hildenbrand wrote:
> > > Of course, other interfaces might make sense.
> > > 
> > > You can then start using these memory blocks and hinder them from
> > > getting onlined (as a safety net) via memory notifiers.
> > > 
> > > That would at least avoid you having to call
> > > add_memory/remove_memory/offline_pages/device_online/modifying
> > > memblock
> > > states manually.
> > 
> > I see what you're saying and that definitely sounds safer.
> > 
> > We would still need to call remove_memory and add_memory from
> > memtrace
> > as
> > just offlining memory doesn't remove it from the linear page tables
> > (if 
> > it's still in the page tables then hardware can prefetch it and if
> > hardware tracing is using it then the box checkstops).
> 
> That prefetching part is interesting (and nasty as well). If we could
> at
> least get rid of the manual onlining/offlining, I would be able to
> sleep
> better at night ;) One step at a time.
> 

What are your thoughts on adding remove to state_store in
drivers/base/memory.c? And an accompanying add? So then userspace could
do "echo remove > memory34/state"? 

Then most of the memtrace code could be moved to a userspace tool. The
only bit that we would need to keep in the kernel is setting up debugfs
files in memtrace_init_debugfs.






[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux