From d2158ada297628242fb87863c11bf25e1031193e Mon Sep 17 00:00:00 2001 From: Tim Deegan Date: Tue, 24 Apr 2007 11:39:13 +0100 Subject: [PATCH] [XEN] Truncate arithmetic for PERFSTATUS counters to the width of perfc_t. Since these are all calculated per-cpu now, a status counter that is incremented on one cpu and decremented on another will underflow on the decrement. When we add the per-cpu values to get the total, if we don't truncate the sum it will be max-perfc + 1 instead of zero. Signed-off-by: Tim Deegan --- xen/common/perfc.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/xen/common/perfc.c b/xen/common/perfc.c index 11e445a0fc..535a1c7092 100644 --- a/xen/common/perfc.c +++ b/xen/common/perfc.c @@ -48,6 +48,8 @@ void perfc_printall(unsigned char key) case TYPE_S_SINGLE: for_each_online_cpu ( cpu ) sum += per_cpu(perfcounters, cpu)[j]; + if ( perfc_info[i].type == TYPE_S_SINGLE ) + sum = (perfc_t) sum; printk("TOTAL[%12Lu]", sum); if ( sum ) { @@ -71,6 +73,8 @@ void perfc_printall(unsigned char key) for ( k = 0; k < perfc_info[i].nr_elements; k++ ) sum += counters[k]; } + if ( perfc_info[i].type == TYPE_S_ARRAY ) + sum = (perfc_t) sum; printk("TOTAL[%12Lu]", sum); if (sum) { @@ -80,6 +84,8 @@ void perfc_printall(unsigned char key) sum = 0; for_each_online_cpu ( cpu ) sum += per_cpu(perfcounters, cpu)[j + k]; + if ( perfc_info[i].type == TYPE_S_ARRAY ) + sum = (perfc_t) sum; if ( (k % 4) == 0 ) printk("\n%16s", ""); printk(" ARR%02u[%10Lu]", k, sum); @@ -94,6 +100,8 @@ void perfc_printall(unsigned char key) sum = 0; for ( n = 0; n < perfc_info[i].nr_elements; n++ ) sum += counters[n]; + if ( perfc_info[i].type == TYPE_S_ARRAY ) + sum = (perfc_t) sum; if ( k > 0 && (k % 4) == 0 ) printk("\n%46s", ""); printk(" CPU%02u[%10Lu]", cpu, sum); -- 2.30.2