On Tue, 26 Aug 2014, Joonsoo Kim wrote: > > What case? SLUB uses a linked list and therefore does not have these > > storage requirements. > > I misunderstand that you mentioned just memory usage. My *any case* > means memory usage of previous SLAB and SLAB with this percpu alloc > change. Sorry for confusion. Ok. True the total amount of memory used does not increase. > > > I know that percpu allocator occupy vmalloc space, so maybe we could > > > exhaust vmalloc space on 32 bit. 64 bit has no problem on it. > > > How many cores does largest 32 bit system have? Is it possible > > > to exhaust vmalloc space if we use percpu allocator? > > > > There were NUMA systems on x86 a while back (not sure if they still > > exists) with 128 or so processors. > > > > Some people boot 32 bit kernels on contemporary servers. The Intel ones > > max out at 18 cores (36 hyperthreaded). I think they support up to 8 > > scokets. So 8 * 36? > > > > > > Its different on other platforms with much higher numbers. Power can > > easily go up to hundreds of hardware threads and SGI Altixes 7 yearsago > > where at 8000 or so. > > Okay... These large systems with 32 bit kernel could be break with this > change. I will do more investigation. Possibly, I will drop this patch. :) Wait the last system mentioned are 64 bit. SGI definitely. Power probably too. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>