| Message ID | 20230213134104.229241-1-ycliang@andestech.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/1] lib/tst_pid.c: Count used pid by traversing /proc | expand |
Hi Leo, > Use "ps -eT | wc -l" to calculate the number of used pid > could have an incorrectly larger result because "ps -eT" > may list the same pid multiple times (with different SPID). > Instead, we could count used pid by traversing /proc > directory and count the subdirectories that have name > composed of digits. > Increase PIDS_RESERVED to avoid fork failure. Thank you! Waiting little longer before merging to give others change to have look. Suggested-by: Petr Vorel <pvorel@suse.cz> Reviewed-by: Petr Vorel <pvorel@suse.cz> Kind regards, Petr
Hi! > Use "ps -eT | wc -l" to calculate the number of used pid > could have an incorrectly larger result because "ps -eT" > may list the same pid multiple times (with different SPID). > > Instead, we could count used pid by traversing /proc > directory and count the subdirectories that have name > composed of digits. > > Increase PIDS_RESERVED to avoid fork failure. The changes looks good, but can we please split the patch into two? We should keep the change to the PIDS_RESERVED separate from the code changes. > Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com> > --- > lib/tst_pid.c | 26 +++++++++++--------------- > 1 file changed, 11 insertions(+), 15 deletions(-) > > diff --git a/lib/tst_pid.c b/lib/tst_pid.c > index 5595e79bd..7582e4828 100644 > --- a/lib/tst_pid.c > +++ b/lib/tst_pid.c > @@ -18,6 +18,7 @@ > * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA > */ > > +#include <ctype.h> > #include <errno.h> > #include <fcntl.h> > #include <limits.h> > @@ -35,7 +36,7 @@ > #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 */ > -#define PIDS_RESERVE 50 > +#define PIDS_RESERVE 200 > > pid_t tst_get_unused_pid_(void (*cleanup_fn) (void)) > { > @@ -113,21 +114,16 @@ 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, max_threads; > - > - f = popen("ps -eT | wc -l", "r"); > - if (!f) { > - tst_brkm(TBROK, cleanup_fn, "Could not run 'ps' to calculate used pids"); > - return -1; > - } > - rc = fscanf(f, "%i", &used_pids); > - pclose(f); > - > - if (rc != 1 || used_pids < 0) { > - tst_brkm(TBROK, cleanup_fn, "Could not read output of 'ps' to calculate used pids"); > - return -1; > + DIR *f; > + struct dirent *ent; > + int max_pids, max_session_pids, max_threads, used_pids = 0; > + > + f = SAFE_OPENDIR("/proc"); > + while ((ent = SAFE_READDIR(f))) { > + if (isdigit(ent->d_name[0])) > + ++used_pids; > } > + SAFE_CLOSEDIR(f); > > SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids); > SAFE_FILE_SCANF(cleanup_fn, THREADS_MAX_PATH, "%d", &max_threads); > -- > 2.34.1 > > > -- > Mailing list info: https://lists.linux.it/listinfo/ltp
Hi Cyril, On Tue, Feb 14, 2023 at 11:58:21AM +0100, Cyril Hrubis wrote: > Hi! > > Use "ps -eT | wc -l" to calculate the number of used pid > > could have an incorrectly larger result because "ps -eT" > > may list the same pid multiple times (with different SPID). > > > > Instead, we could count used pid by traversing /proc > > directory and count the subdirectories that have name > > composed of digits. > > > > Increase PIDS_RESERVED to avoid fork failure. > > The changes looks good, but can we please split the patch into two? > > We should keep the change to the PIDS_RESERVED separate from the code > changes. > Got it! Will send a v3 ASAP! Best regards, Leo > > Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com> > > --- > > lib/tst_pid.c | 26 +++++++++++--------------- > > 1 file changed, 11 insertions(+), 15 deletions(-) > > > > diff --git a/lib/tst_pid.c b/lib/tst_pid.c > > index 5595e79bd..7582e4828 100644 > > --- a/lib/tst_pid.c > > +++ b/lib/tst_pid.c > > @@ -18,6 +18,7 @@ > > * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA > > */ > > > > +#include <ctype.h> > > #include <errno.h> > > #include <fcntl.h> > > #include <limits.h> > > @@ -35,7 +36,7 @@ > > #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 */ > > -#define PIDS_RESERVE 50 > > +#define PIDS_RESERVE 200 > > > > pid_t tst_get_unused_pid_(void (*cleanup_fn) (void)) > > { > > @@ -113,21 +114,16 @@ 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, max_threads; > > - > > - f = popen("ps -eT | wc -l", "r"); > > - if (!f) { > > - tst_brkm(TBROK, cleanup_fn, "Could not run 'ps' to calculate used pids"); > > - return -1; > > - } > > - rc = fscanf(f, "%i", &used_pids); > > - pclose(f); > > - > > - if (rc != 1 || used_pids < 0) { > > - tst_brkm(TBROK, cleanup_fn, "Could not read output of 'ps' to calculate used pids"); > > - return -1; > > + DIR *f; > > + struct dirent *ent; > > + int max_pids, max_session_pids, max_threads, used_pids = 0; > > + > > + f = SAFE_OPENDIR("/proc"); > > + while ((ent = SAFE_READDIR(f))) { > > + if (isdigit(ent->d_name[0])) > > + ++used_pids; > > } > > + SAFE_CLOSEDIR(f); > > > > SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids); > > SAFE_FILE_SCANF(cleanup_fn, THREADS_MAX_PATH, "%d", &max_threads); > > -- > > 2.34.1 > > > > > > -- > > Mailing list info: https://lists.linux.it/listinfo/ltp > > -- > Cyril Hrubis > chrubis@suse.cz
diff --git a/lib/tst_pid.c b/lib/tst_pid.c index 5595e79bd..7582e4828 100644 --- a/lib/tst_pid.c +++ b/lib/tst_pid.c @@ -18,6 +18,7 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#include <ctype.h> #include <errno.h> #include <fcntl.h> #include <limits.h> @@ -35,7 +36,7 @@ #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 */ -#define PIDS_RESERVE 50 +#define PIDS_RESERVE 200 pid_t tst_get_unused_pid_(void (*cleanup_fn) (void)) { @@ -113,21 +114,16 @@ 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, max_threads; - - f = popen("ps -eT | wc -l", "r"); - if (!f) { - tst_brkm(TBROK, cleanup_fn, "Could not run 'ps' to calculate used pids"); - return -1; - } - rc = fscanf(f, "%i", &used_pids); - pclose(f); - - if (rc != 1 || used_pids < 0) { - tst_brkm(TBROK, cleanup_fn, "Could not read output of 'ps' to calculate used pids"); - return -1; + DIR *f; + struct dirent *ent; + int max_pids, max_session_pids, max_threads, used_pids = 0; + + f = SAFE_OPENDIR("/proc"); + while ((ent = SAFE_READDIR(f))) { + if (isdigit(ent->d_name[0])) + ++used_pids; } + SAFE_CLOSEDIR(f); SAFE_FILE_SCANF(cleanup_fn, PID_MAX_PATH, "%d", &max_pids); SAFE_FILE_SCANF(cleanup_fn, THREADS_MAX_PATH, "%d", &max_threads);
Use "ps -eT | wc -l" to calculate the number of used pid could have an incorrectly larger result because "ps -eT" may list the same pid multiple times (with different SPID). Instead, we could count used pid by traversing /proc directory and count the subdirectories that have name composed of digits. Increase PIDS_RESERVED to avoid fork failure. Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com> --- lib/tst_pid.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-)