Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH 4/5] powernv:idle: Move initialization of sibling pacas to pnv_alloc_idle_core_states | Date | Mon, 10 Jul 2017 14:34:08 +1000 |
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Nicholas Piggin <npiggin@gmail.com> writes: > On Fri, 7 Jul 2017 20:34:16 +0530 > Gautham R Shenoy <ego@linux.vnet.ibm.com> wrote: >> On Fri, Jul 07, 2017 at 01:16:09AM +1000, Nicholas Piggin wrote: >> > >> > Speaking of which... core_idle_state and thread_sibling_pacas are >> > allocated with kmalloc_node... What happens if we take an SLB miss >> > in the idle wakeup code on these guys? Nothing good I think. Perhaps >> > we should put them into the pacas or somewhere in bolted memory. >> >> Yes, though the SLB miss hasn't yet been encountered in practise so >> far! > > Considering it's a node-affine allocation, it may actually be possible > to hit in practice on very large memory systems in practice.
You can boot with disable_1tb_segments on the kernel command line to increase the change of hitting it.
cheers
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