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powerpc/64s/hash: Use POWER9 SLBIA IH=3 variant in switch_slb

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POWER9 introduces SLBIA IH=3, which invalidates all SLB entries and
associated lookaside information that have a class value of 1, which
Linux assigns to user addresses. This matches what switch_slb wants,
and allows a simple fast implementation that avoids the slb_cache
complexity.

As a side-effect, the POWER5 < DD2.1 SLB invalidation workaround is
also avoided on POWER9.

Process context switching rate is improved about 2.2% for a small
process that hits the slb cache which is the best case for the current
code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin
2018-09-15 01:30:50 +10:00
committed by Michael Ellerman
parent 5141c182d7
commit 82d8f4c22f
2 changed files with 55 additions and 39 deletions
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11
arch/powerpc/xmon/xmon.c
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@@ -2393,10 +2393,13 @@ static void dump_one_paca(int cpu)
}
}
DUMP(p, vmalloc_sllp, "%#-*x");
DUMP(p, slb_cache_ptr, "%#-*x");
for (i = 0; i < SLB_CACHE_ENTRIES; i++)
printf(" %-*s[%d] = 0x%016x\n",
22, "slb_cache", i, p->slb_cache[i]);
if (!early_cpu_has_feature(CPU_FTR_ARCH_300)) {
DUMP(p, slb_cache_ptr, "%#-*x");
for (i = 0; i < SLB_CACHE_ENTRIES; i++)
printf(" %-*s[%d] = 0x%016x\n",
22, "slb_cache", i, p->slb_cache[i]);
}
DUMP(p, rfi_flush_fallback_area, "%-*px");
#endif