[LTP] [PATCH v2] lib/mem.c: handle the case oom0{3, 5} exit with 'EAGAIN' situation

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> From: "Li Wang" <liwang@redhat.com>
> To: "Jan Stancek" <jstancek@redhat.com>
> Cc: ltp@lists.linux.it
> Sent: Tuesday, 22 September, 2015 9:50:39 AM
> Subject: Re: [LTP] [PATCH v2] lib/mem.c: handle the case oom0{3, 5} exit with 'EAGAIN' situation
> 
> Hi,
> 
> 
> On Thu, Sep 17, 2015 at 11:10 AM, Li Wang <liwang@redhat.com> wrote:
> 
> > Hi,
> >
> > On Wed, Sep 16, 2015 at 8:12 PM, Jan Stancek <jstancek@redhat.com> wrote:
> >
> >>
> >>
> >>
> >>
> >> ----- Original Message -----
> >> > From: "Li Wang" <liwang@redhat.com>
> >> > To: ltp@lists.linux.it
> >> > Sent: Wednesday, 16 September, 2015 11:55:32 AM
> >> > Subject: [LTP] [PATCH v2] lib/mem.c: handle the case oom0{3,  5} exit
> >> with 'EAGAIN' situation
> >> >
> >> > v1 --> v2
> >> >       1. limited the number of loops
> >> >       2. added the usleep(300) to wait resource freed
> >> >
> >> > Sometimes oom0{3,5} failed as the following results:
> >> >
> >> > oom05       0  TINFO  :  start OOM testing for mlocked pages.
> >> > oom05       0  TINFO  :  expected victim is 3371.
> >> > oom05       0  TINFO  :  thread (3fff788ff1c0), allocating 3221225472
> >> bytes.
> >> > ...
> >> > oom05       5  TFAIL  :  mem.c:153: victim unexpectedly ended with
> >> retcode:
> >> > 11, expected: 12
> >> >
> >> > In the OOM test, that tries to consume all memory. But the test doesn't
> >> retry
> >> > to mlock, it simply
> >> > exits with errno returned by mlock. At the moment testcase is expecting
> >> > either ENOMEM or getting
> >> > killed by kernel.
> >> >
> >> > Here do retry the function if mlock() fail with 'EAGAIN' errno.
> >> >
> >> > Signed-off-by: Li Wang <liwang@redhat.com>
> >> > ---
> >> >  testcases/kernel/mem/lib/mem.c | 12 ++++++++++--
> >> >  1 file changed, 10 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git a/testcases/kernel/mem/lib/mem.c
> >> b/testcases/kernel/mem/lib/mem.c
> >> > index 8fe4bf0..b8a55e2 100644
> >> > --- a/testcases/kernel/mem/lib/mem.c
> >> > +++ b/testcases/kernel/mem/lib/mem.c
> >> > @@ -30,6 +30,7 @@ static int alloc_mem(long int length, int testcase)
> >> >  {
> >> >       char *s;
> >> >       long i, pagesz = getpagesize();
> >> > +     int loop = 10;
> >> >
> >> >       tst_resm(TINFO, "thread (%lx), allocating %ld bytes.",
> >> >               (unsigned long) pthread_self(), length);
> >> > @@ -39,8 +40,15 @@ static int alloc_mem(long int length, int testcase)
> >> >       if (s == MAP_FAILED)
> >> >               return errno;
> >> >
> >> > -     if (testcase == MLOCK && mlock(s, length) == -1)
> >> > -             return errno;
> >> > +     if (testcase == MLOCK) {
> >> > +             while (mlock(s, length) == -1 && loop > 0) {
> >> > +                     if (EAGAIN != errno)
> >> > +                             return errno;
> >> > +                     usleep(300);
> >>
> >> usleep is in microseconds, so this wouldn't give system much time.
> >>
> >
> Sorry, Ping.
> 
> Would you mind if I sent V3 with usleep(300000)? or any other advice?

No need. I changed it (along with small changes to description) and pushed.

Regards,
Jan

> 
> 
> --
> Regards,
> Li Wang
> Email: liwang@redhat.com
>