From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: ltp@lists.linux.it
Subject: [LTP] [PATCH v2 2/3] syscalls/msgstress03: fix fork failure on small memory systems
Date: Wed, 23 Jun 2021 15:55:20 +0200 [thread overview]
Message-ID: <20210623135524.80663-4-krzysztof.kozlowski@canonical.com> (raw)
In-Reply-To: <20210623135524.80663-1-krzysztof.kozlowski@canonical.com>
Running syscalls/msgstress03 on a system with less than ~4 GB of RAM fails:
msgstress03 1 TFAIL : msgstress03.c:155: Fork failed (may be OK if under stress)
In dmesg:
LTP: starting msgstress03
cgroup: fork rejected by pids controller in /user.slice/user-1000.slice/session-1.scope
The reason is cgroups pid limit set by systemd user.slice. The limit is
set for login session, also for root user. For example on 2 GB RAM
machine it is set as:
/sys/fs/cgroup/pids/user.slice/user-0.slice/pids.max:5207
Read the maximum number of pids and adjust the test limit. For 2 GB RAM
machine with systemd this will result in:
msgstress03 0 TINFO : Found limit of processes 5056 (from /sys/fs/cgroup/pids/user.slice/user-1000.slice/pids.max)
msgstress03 0 TINFO : Requested number of processes higher than user session limit (10000 > 4556), setting to 4556
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
---
.../kernel/syscalls/ipc/msgstress/msgstress03.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c b/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c
index 294b401b1b38..18e50e35ee07 100644
--- a/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c
+++ b/testcases/kernel/syscalls/ipc/msgstress/msgstress03.c
@@ -78,7 +78,7 @@ static void usage(void)
int main(int argc, char **argv)
{
- int i, j, ok, pid;
+ int i, j, ok, pid, free_pids;
int count, status;
struct sigaction act;
@@ -109,6 +109,19 @@ int main(int argc, char **argv)
}
}
+ free_pids = tst_get_free_pids(cleanup);
+ if (free_pids < 0) {
+ tst_brkm(TBROK, cleanup, "Can't obtain free_pid count");
+ } else if (!free_pids) {
+ tst_brkm(TBROK, cleanup, "No free pids");
+ }
+ if (nprocs >= free_pids) {
+ tst_resm(TINFO,
+ "Requested number of processes higher than limit (%d > %d), "
+ "setting to %d", nprocs, free_pids, free_pids);
+ nprocs = free_pids;
+ }
+
srand(getpid());
tid = -1;
--
2.27.0
next prev parent reply other threads:[~2021-06-23 13:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 13:55 [LTP] [PATCH v2 0/4] syscalls/msgstress: fixes for small systems Krzysztof Kozlowski
2021-06-23 13:55 ` [LTP] [PATCH v2 1/4] include/tst_pid.h: fix language typo (subtraction) Krzysztof Kozlowski
2021-06-23 13:55 ` [LTP] [PATCH v2 1/3] syscalls/msgstress04: fix fork failure on small memory systems Krzysztof Kozlowski
2021-06-23 13:55 ` Krzysztof Kozlowski [this message]
2021-06-23 13:55 ` [LTP] [PATCH v2 2/4] " Krzysztof Kozlowski
2021-06-23 13:55 ` [LTP] [PATCH v2 3/4] syscalls/msgstress03: " Krzysztof Kozlowski
2021-06-23 13:55 ` [LTP] [PATCH v2 3/3] syscalls/msgstress: tune limit of processes for small machines Krzysztof Kozlowski
2021-06-23 13:55 ` [LTP] [PATCH v2 4/4] " Krzysztof Kozlowski
2021-06-23 13:58 ` [LTP] [PATCH v2 0/4] syscalls/msgstress: fixes for small systems Krzysztof Kozlowski
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