On 20/12/2022 10:45, Teo Couprie Diaz wrote:
In our debian-based distribution, the two files used in lib/tst_pid are not available, but systemd still imposes a task limit far lesser than the kernel pid_max. Add another file that seems to be always available to read the maximum number of PIDs.
This fixed msgstress04, but it appeared that msgstress03 didn't account for all of its PIDs, so it still hit the limit. Reduce the number of free PIDs by 10% in msgstress03 to account for it.
Signed-off-by: Teo Couprie Diaz teo.coupriediaz@arm.com
lib/tst_pid.c | 4 ++++ testcases/kernel/syscalls/ipc/msgstress/msgstress03.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/lib/tst_pid.c b/lib/tst_pid.c index 21cadef2a..3c10e0298 100644 --- a/lib/tst_pid.c +++ b/lib/tst_pid.c @@ -33,6 +33,7 @@ #define PID_MAX_PATH "/proc/sys/kernel/pid_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" +#define CGROUPS_V2_INIT_SCOPE "/sys/fs/cgroup/pids/init.scope/pids.max"
On Arch I don't get pids/ under cgroup/, what I have is init.scope/ directly underneath, that is:
/sys/fs/cgroup/init.scope/pids.max
Not sure if that's a configuration difference? In any case the idea sounds sensible.
/* Leave some available processes for the OS */ #define PIDS_RESERVE 50 @@ -103,6 +104,9 @@ static int get_session_pids_limit(void (*cleanup_fn) (void)) if (max_pids < 0) max_pids = read_session_pids_limit(CGROUPS_V1_SLICE_FMT, uid, cleanup_fn);
- if (max_pids < 0)
max_pids = read_session_pids_limit(CGROUPS_V2_INIT_SCOPE, uid,cleanup_fn);if (max_pids < 0) return -1; diff --git a/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c b/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c index 3cb70ab18..f0a631479 100644 --- a/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c +++ b/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c @@ -109,7 +109,7 @@ int main(int argc, char **argv) } }
- free_pids = tst_get_free_pids(cleanup);
- free_pids = tst_get_free_pids(cleanup) * 0.9;
Floating point calculations on integers are typically avoided if possible, you could simply use * 9 / 10 here. Otherwise that idea sounds sensible to me too, I found it quite strange that the test attempts to use literally all the remaining PIDs in fact.
Kevin
if (nprocs >= free_pids) { tst_resm(TINFO, "Requested number of processes higher than limit (%d > %d), "