Messages in this thread Patch in this message | | | Date | Fri, 22 Jun 2012 08:12:12 -0500 | From | Cliff Wickman <> | Subject | [PATCH 1/3] x86: UV BAU destination timeout period |
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Correct the calculation of a destination timeout period, which is used to distinguish between a destination timeout and the situation where all the target software ack resources are full and a request is returned immediately.
The problem is that integer arithmetic was overflowing, yielding a very large result.
Without this fix destination timeouts are identified as resource 'plugged' events and an ipi method of resource releasing is unnecessarily employed.
Signed-off-by: Cliff Wickman <cpw@sgi.com> --- arch/x86/platform/uv/tlb_uv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux/arch/x86/platform/uv/tlb_uv.c =================================================================== --- linux.orig/arch/x86/platform/uv/tlb_uv.c +++ linux/arch/x86/platform/uv/tlb_uv.c @@ -1811,8 +1811,8 @@ static int calculate_destination_timeout index = (mmr_image >> BAU_URGENCY_7_SHIFT) & BAU_URGENCY_7_MASK; mmr_image = uv_read_local_mmr(UVH_TRANSACTION_TIMEOUT); mult2 = (mmr_image >> BAU_TRANS_SHIFT) & BAU_TRANS_MASK; - base = timeout_base_ns[index]; - ts_ns = base * mult1 * mult2; + ts_ns = timeout_base_ns[index]; + ts_ns *= (mult1 * mult2); ret = ts_ns / 1000; } else { /* 4 bits 0/1 for 10/80us base, 3 bits of multiplier */
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