Re: [PATCH] sparc64: Handle extremely large kernel TSB range flushes sanely.

[David Miller <davem@davemloft.net>]

From: James Clarke <jrtc27@jrtc27.com>
Date: Thu, 27 Oct 2016 09:25:36 +0100

> Iʼve run it on the T5 and it seems to work without lockups:
> 
> [5948090.988821] vln_init: *vmap_lazy_nr is 32754
> [5948090.989943] vln_init: lazy_max_pages() is 32768
> [5948091.157381] TSB[insmod:261876]: DEBUG flush_tsb_kernel_range start=0000000010006000 end=00000000f0000000 PAGE_SIZE=2000
> [5948091.157530] TSB[insmod:261876]: DEBUG flush_tsb_kernel_range start=0000000100000000 end=0005ffff8c000000 PAGE_SIZE=2000
> [5948091.158240] vln_init: vmap_lazy_nr is caeb1c
> [5948091.158252] vln_init: *vmap_lazy_nr is 0
> [5948091.159311] vln_init: lazy_max_pages() is 32768
> ... continues on as normal ...
> 
> (again, thatʼs my debugging module to see how close the system is to a flush)
> 
> I can't (yet) vouch for the IIIi, but when it comes back up Iʼll give it a go[1].
> I'll also put it on the T1 at some point today, but it *should* also work since
> it's using the same sun4v/hypervisor implementation as the T5.

I'm about to test it on my IIIi and will commit this if it seems to work properly.

I guess you have no opinion about the cut-off choosen? :-)

Anyways, we can fine tune it later.