2021-04-23 08:37:51

by zhouchuangao

Subject: [PATCH] mips/kvm: Use BUG_ON instead of if condition followed by BUG

BUG_ON uses unlikely in if(), it can be optimized at compile time.

Usually, the condition in if() is not satisfied. In my opinion,
this can improve the efficiency of the multi-stage pipeline.

Signed-off-by: zhouchuangao <[email protected]>
---
arch/mips/kvm/tlb.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c
index 1088114..a3b50d5 100644
--- a/arch/mips/kvm/tlb.c
+++ b/arch/mips/kvm/tlb.c
@@ -58,8 +58,7 @@ static int _kvm_mips_host_tlb_inv(unsigned long entryhi)
tlb_probe_hazard();
idx = read_c0_index();

- if (idx >= current_cpu_data.tlbsize)
- BUG();
+ BUG_ON(idx >= current_cpu_data.tlbsize);

if (idx >= 0) {
write_c0_entryhi(UNIQUE_ENTRYHI(idx));
--
2.7.4

2021-06-21 09:55:40

by Thomas Bogendoerfer

Subject: Re: [PATCH] mips/kvm: Use BUG_ON instead of if condition followed by BUG

On Fri, Apr 23, 2021 at 01:35:09AM -0700, zhouchuangao wrote:
> BUG_ON uses unlikely in if(), it can be optimized at compile time.
>
> Usually, the condition in if() is not satisfied. In my opinion,
> this can improve the efficiency of the multi-stage pipeline.
>
> Signed-off-by: zhouchuangao <[email protected]>
> ---
> arch/mips/kvm/tlb.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)

applied to mips-next.

Thomas.

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