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Read KTR_CPU into a temporary variable so that we use a consistent value

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for both the cpumask check and the cpu entry field w/o needing to use
a critical section.
This commit is contained in:
John Baldwin 2002-03-08 18:55:59 +00:00
parent 552c7f1b18
commit c29824db05
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=91904
1 changed files with 4 additions and 7 deletions
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11
sys/kern/kern_ktr.c
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@ -120,8 +120,8 @@ ktr_tracepoint(u_int mask, const char *format, u_long arg1, u_long arg2,
{
struct ktr_entry *entry;
int newindex, saveindex;
critical_t savecrit;
struct thread *td;
int cpu;
#ifdef KTR_EXTEND
va_list ap;
#endif
@ -133,19 +133,16 @@ ktr_tracepoint(u_int mask, const char *format, u_long arg1, u_long arg2,
td = curthread;
if (td->td_inktr)
return;
savecrit = cpu_critical_enter();
if (((1 << KTR_CPU) & ktr_cpumask) == 0) {
cpu_critical_exit(savecrit);
cpu = KTR_CPU;
if (((1 << cpu) & ktr_cpumask) == 0)
return;
}
td->td_inktr++;
do {
saveindex = ktr_idx;
newindex = (saveindex + 1) & (KTR_ENTRIES - 1);
} while (atomic_cmpset_rel_int(&ktr_idx, saveindex, newindex) == 0);
entry = &ktr_buf[saveindex];
entry->ktr_cpu = KTR_CPU;
cpu_critical_exit(savecrit);
entry->ktr_cpu = cpu;
nanotime(&entry->ktr_tv);
#ifdef KTR_EXTEND
entry->ktr_filename = filename;