[LTP] [PATCH 1/1] tst_pids.c: fix fork failure on small memory systems

[Leo Liang]

Hi Cyril,

On Thu, Feb 09, 2023 at 02:05:46PM +0100, Cyril Hrubis wrote:
> Hi!
> >  lib/tst_pid.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/tst_pid.c b/lib/tst_pid.c
> > index 21cadef2a..3fb3f39ad 100644
> > --- a/lib/tst_pid.c
> > +++ b/lib/tst_pid.c
> > @@ -31,6 +31,7 @@
> >  #include "tst_safe_macros.h"
> >  
> >  #define PID_MAX_PATH "/proc/sys/kernel/pid_max"
> > +#define THREADS_MAX_PATH "/proc/sys/kernel/threads-max"
> >  #define CGROUPS_V1_SLICE_FMT "/sys/fs/cgroup/pids/user.slice/user-%d.slice/pids.max"
> >  #define CGROUPS_V2_SLICE_FMT "/sys/fs/cgroup/user.slice/user-%d.slice/pids.max"
> >  /* Leave some available processes for the OS */
> > @@ -113,7 +114,7 @@ static int get_session_pids_limit(void (*cleanup_fn) (void))
> >  int tst_get_free_pids_(void (*cleanup_fn) (void))
> >  {
> >  	FILE *f;
> > -	int rc, used_pids, max_pids, max_session_pids;
> > +	int rc, used_pids, max_pids, max_session_pids, max_threads;
> >  
> >  	f = popen("ps -eT | wc -l", "r");
> >  	if (!f) {
> > @@ -129,6 +130,8 @@ int tst_get_free_pids_(void (*cleanup_fn) (void))
> >  	}
> >  
> >  	SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids);
> > +	SAFE_FILE_SCANF(cleanup_fn, THREADS_MAX_PATH, "%d", &max_threads);
> > +	max_pids = (max_pids < max_threads) ? max_pids : max_threads;
> 
> BTW: We do have a MIN() macro definition in tst_minmax.h header so we
>      can just do max_pids = MIN(max_pids, max_threads);
> 

Thanks for the review!
Will send a v2 to fix this!

Best regards,
Leo

> >  	max_session_pids = get_session_pids_limit(cleanup_fn);
> >  	if ((max_session_pids > 0) && (max_session_pids < max_pids))
> 
> Otherwise:
> 
> Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz