Messages in this thread | | | Date | Tue, 9 Jul 2019 15:09:14 -0500 | From | Russ Anderson <> | Subject | Re: [PATCH v2 8/9] x86/mm/tlb: Remove UV special case |
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On Tue, Jul 09, 2019 at 09:50:27PM +0200, Thomas Gleixner wrote: > On Tue, 2 Jul 2019, Nadav Amit wrote: > > > SGI UV support is outdated and not maintained, and it is not clear how > > it performs relatively to non-UV. Remove the code to simplify the code. > > You should at least Cc the SGI/HP folks on that. They are still > around. Done so.
Thanks Thomas. The SGI UV is now HPE Superdome Flex and is very much still supported.
Thanks.
> > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Dave Hansen <dave.hansen@intel.com> > > Suggested-by: Andy Lutomirski <luto@kernel.org> > > Signed-off-by: Nadav Amit <namit@vmware.com> > > --- > > arch/x86/mm/tlb.c | 25 ------------------------- > > 1 file changed, 25 deletions(-) > > > > diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c > > index b47a71820f35..64afe1215495 100644 > > --- a/arch/x86/mm/tlb.c > > +++ b/arch/x86/mm/tlb.c > > @@ -689,31 +689,6 @@ void native_flush_tlb_multi(const struct cpumask *cpumask, > > trace_tlb_flush(TLB_REMOTE_SEND_IPI, > > (info->end - info->start) >> PAGE_SHIFT); > > > > - if (is_uv_system()) { > > - /* > > - * This whole special case is confused. UV has a "Broadcast > > - * Assist Unit", which seems to be a fancy way to send IPIs. > > - * Back when x86 used an explicit TLB flush IPI, UV was > > - * optimized to use its own mechanism. These days, x86 uses > > - * smp_call_function_many(), but UV still uses a manual IPI, > > - * and that IPI's action is out of date -- it does a manual > > - * flush instead of calling flush_tlb_func_remote(). This > > - * means that the percpu tlb_gen variables won't be updated > > - * and we'll do pointless flushes on future context switches. > > - * > > - * Rather than hooking native_flush_tlb_multi() here, I think > > - * that UV should be updated so that smp_call_function_many(), > > - * etc, are optimal on UV. > > - */ > > - flush_tlb_func_local(info); > > - > > - cpumask = uv_flush_tlb_others(cpumask, info); > > - if (cpumask) > > - smp_call_function_many(cpumask, flush_tlb_func_remote, > > - (void *)info, 1); > > - return; > > - } > > - > > /* > > * If no page tables were freed, we can skip sending IPIs to > > * CPUs in lazy TLB mode. They will flush the CPU themselves > > -- > > 2.17.1 > > > >
-- Russ Anderson, SuperDome Flex Linux Kernel Group Manager HPE - Hewlett Packard Enterprise (formerly SGI) rja@hpe.com
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