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Subject[PATCH 04/20] riscv: optimize send_ipi_single
Date
Don't go through send_ipi_mask, but just set the op bit an then pass a
simple generate hartid mask directly to sbi_send_ipi.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
---
arch/riscv/kernel/smp.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 2e21669aa068..a3715d621f60 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -94,7 +94,13 @@ static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)

static void send_ipi_single(int cpu, enum ipi_message_type op)
{
- send_ipi_mask(cpumask_of(cpu), op);
+ int hartid = cpuid_to_hartid_map(cpu);
+
+ smp_mb__before_atomic();
+ set_bit(op, &ipi_data[cpu].bits);
+ smp_mb__after_atomic();
+
+ sbi_send_ipi(cpumask_bits(cpumask_of(hartid)));
}

static inline void clear_ipi(void)
--
2.20.1
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