On Tue, Apr 05, 2022 at 12:13:33AM +0000, Oliver Upton wrote:
> Hi Ricardo,
>
> On Mon, Apr 04, 2022 at 02:46:40PM -0700, Ricardo Koller wrote:
> > Add is_cpu_eligible_to_run() utility function, which checks whether the current
> > process, or one of its threads, is eligible to run on a particular CPU.
> > This information is obtained using sched_getaffinity.
> >
> > Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx>
> > ---
> > .../testing/selftests/kvm/include/test_util.h | 2 ++
> > tools/testing/selftests/kvm/lib/test_util.c | 20 ++++++++++++++++++-
> > 2 files changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
> > index 99e0dcdc923f..a7653f369b6c 100644
> > --- a/tools/testing/selftests/kvm/include/test_util.h
> > +++ b/tools/testing/selftests/kvm/include/test_util.h
> > @@ -143,4 +143,6 @@ static inline void *align_ptr_up(void *x, size_t size)
> > return (void *)align_up((unsigned long)x, size);
> > }
> >
> > +bool is_cpu_eligible_to_run(int pcpu);
> > +
> > #endif /* SELFTEST_KVM_TEST_UTIL_H */
> > diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
> > index 6d23878bbfe1..7813a68333c0 100644
> > --- a/tools/testing/selftests/kvm/lib/test_util.c
> > +++ b/tools/testing/selftests/kvm/lib/test_util.c
> > @@ -4,6 +4,7 @@
> > *
> > * Copyright (C) 2020, Google LLC.
> > */
> > +#define _GNU_SOURCE
> >
> > #include <assert.h>
> > #include <ctype.h>
> > @@ -13,7 +14,9 @@
> > #include <sys/stat.h>
> > #include <sys/syscall.h>
> > #include <linux/mman.h>
> > -#include "linux/kernel.h"
> > +#include <linux/kernel.h>
> > +#include <sched.h>
> > +#include <sys/sysinfo.h>
> >
> > #include "test_util.h"
> >
> > @@ -334,3 +337,18 @@ long get_run_delay(void)
> >
> > return val[1];
> > }
> > +
> > +bool is_cpu_eligible_to_run(int pcpu)
> > +{
> > + cpu_set_t cpuset;
> > + long i, nprocs;
> > +
> > + nprocs = get_nprocs_conf();
> > + sched_getaffinity(0, sizeof(cpu_set_t), &cpuset);
> > + for (i = 0; i < nprocs; i++) {
> > + if (i == pcpu)
> > + return CPU_ISSET(i, &cpuset);
> > + }
>
> I don't think you need the loop and can just do CPU_ISSET(pcpu, &cpuset),
> right?
Oops, definitely not. Thanks for catching this.
>
> --
> Thanks,
> Oliver
