Avoid SMP calls for flushing small icache ranges. On non-CM platforms,
and CM platforms too after we make r4k_on_each_cpu() take the cache op
type into account, it will be called on multiple CPUs due to the
possibility that local_r4k_flush_icache_range_ipi() could do
non-globalized indexed cache ops. This rougly copies the range size
check out into r4k_flush_icache_range(), which can disallow indexed
cache ops and allow r4k_on_each_cpu() to skip the SMP call.
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Leonid Yegoshin <leonid.yegoshin@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/mm/c-r4k.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index cfcb336f57a0..8016babe5c84 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -784,12 +784,33 @@ static inline void local_r4k_flush_icache_range_ipi(void *args)
static void r4k_flush_icache_range(unsigned long start, unsigned long end)
{
struct flush_icache_range_args args;
+ unsigned long size, cache_size;
args.start = start;
args.end = end;
args.type = R4K_HIT | R4K_INDEX;
+ /*
+ * Indexed cache ops require an SMP call.
+ * Consider if that can or should be avoided.
+ */
+ preempt_disable();
+ if (r4k_op_needs_ipi(R4K_INDEX) && !r4k_op_needs_ipi(R4K_HIT)) {
+ /*
+ * If address-based cache ops don't require an SMP call, then
+ * use them exclusively for small flushes.
+ */
+ size = start - end;
+ cache_size = icache_size;
+ if (!cpu_has_ic_fills_f_dc) {
+ size *= 2;
+ cache_size += dcache_size;
+ }
+ if (size <= cache_size)
+ args.type &= ~R4K_INDEX;
+ }
r4k_on_each_cpu(args.type, local_r4k_flush_icache_range_ipi, &args);
+ preempt_enable();
instruction_hazard();
}
--
2.4.10
