Re: [LTP] [PATCH v3 1/4] Hugetlb: Add new tst_test options for hugeltb test support

Tarun Sahu
2022-10-31T19:25:53Z

On Oct 31 2022, Cyril Hrubis wrote:
> Hi!
> > extern unsigned int tst_variant;
> > -
> > +extern int tst_hugetlb_fd;
> > #define TST_NO_HUGEPAGES ((unsigned long)-1)
> >
> > #define TST_UNLIMITED_RUNTIME (-1)
> > @@ -176,6 +176,18 @@ struct tst_test {
> > int all_filesystems:1;
> > int skip_in_lockdown:1;
> > int skip_in_compat:1;
> > + /*
> > + * If set, the test function will create a hugetlbfs mount point
> > + * at /tmp/xxxxxx, where xxxxxx is a random string.
> > + */
> > + int needs_hugetlbfs:1;
> > + /*
> > + * If set, the test function will create and open a random file
> > + * under mounted hugetlbfs. To use this option, needs_hugetlbfs must
> > + * be set. The file descriptior will be set in tst_hugetlb_fd.
> > + * The close(tst_hugetlb_fd) will be called on test exit(cleanup).
> > + */
> > + int needs_unlinked_hugetlb_file:1;
> >
> > /*
> > * The skip_filesystems is a NULL terminated list of filesystems the
> > @@ -357,6 +369,12 @@ unsigned int tst_remaining_runtime(void);
> > */
> > void tst_set_max_runtime(int max_runtime);
> >
> > +/*
> > + * Create and open a random file inside the given dir path.
> > + * It unlinks the file after opening and return file descriptor.
> > + */
> > +int tst_create_unlinked_file(const char *path);
> > +
> > /*
> > * Returns path to the test temporary directory in a newly allocated buffer.
> > */
> > diff --git a/lib/tst_test.c b/lib/tst_test.c
> > index 8ccde1629..43cba1004 100644
> > --- a/lib/tst_test.c
> > +++ b/lib/tst_test.c
> > @@ -925,7 +925,8 @@ static int needs_tmpdir(void)
> > tst_test->needs_device ||
> > tst_test->mntpoint ||
> > tst_test->resource_files ||
> > - tst_test->needs_checkpoints;
> > + tst_test->needs_checkpoints ||
> > + tst_test->needs_hugetlbfs;
> > }
> >
> > static void copy_resources(void)
> > @@ -1021,6 +1022,30 @@ static void prepare_and_mount_dev_fs(const char *mntpoint)
> > }
> > }
> >
> > +static void prepare_and_mount_hugetlb_fs(void)
> > +{
> > + tst_test->mntpoint = tst_get_tmpdir();
> > + SAFE_MOUNT("none", tst_test->mntpoint, "hugetlbfs", 0, NULL);
> > + mntpoint_mounted = 1;
> > +}
> > +
> > +int tst_create_unlinked_file(const char *path)
> > +{
> > + char template[PATH_MAX];
> > + int fd;
> > +
> > + snprintf(template, PATH_MAX, "%s/ltp_%.3sXXXXXX",
> > + path, TCID);
> > +
> > + fd = mkstemp(template);
> > + if (fd < 0)
> > + tst_brk(TBROK | TERRNO,
> > + "%s: mkstemp(%s) failed", __func__, template);
> > +
> > + SAFE_UNLINK(template);
> > + return fd;
> > +}
> > +
> > static const char *limit_tmpfs_mount_size(const char *mnt_data,
> > char *buf, size_t buf_size, const char *fs_type)
> > {
> > @@ -1094,6 +1119,8 @@ static void do_cgroup_requires(void)
> > tst_cg_init();
> > }
> >
> > +int tst_hugetlb_fd = -1;
> > +
> > static void do_setup(int argc, char *argv[])
> > {
> > if (!tst_test)
> > @@ -1217,6 +1244,17 @@ static void do_setup(int argc, char *argv[])
> > }
> > }
> >
> > + if (tst_test->needs_hugetlbfs)
> > + prepare_and_mount_hugetlb_fs();
> > +
> > + if (tst_test->needs_unlinked_hugetlb_file) {
> > + if (!(tst_test->needs_hugetlbfs)) {
> > + tst_brk(TBROK, "Option needs_unlinked_hugetlb_file "
> > + "requires option needs_hugetlbfs");
> > + }
> > + tst_hugetlb_fd = tst_create_unlinked_file(tst_test->mntpoint);
> > + }
>
> The function tst_create_unlinked_file() looks useful, but I do not think
> that adding the needs_unlinked_hugetlb_file flag simplifies things that
> much. Also this will not scale well when we would need two
> filedescripors like that. Maybe we it would be cleaner to add only the
> mount/umount functionality to the test library and call the
> tst_create_unlinked_file() in the test setup in the testcases.
>
yes I agree, There is a test that requires two such unlinked file,
there is one that requires one hugetlb and one normal such unlinked file.

> > if (tst_test->needs_device && !mntpoint_mounted) {
> > tdev.dev = tst_acquire_device_(NULL, tst_test->dev_min_size);
> >
> > @@ -1299,8 +1337,15 @@ static void do_cleanup(void)
> > if (ovl_mounted)
> > SAFE_UMOUNT(OVL_MNT);
> >
> > - if (mntpoint_mounted)
> > - tst_umount(tst_test->mntpoint);
> > + if (tst_hugetlb_fd >= 0)
> > + SAFE_CLOSE(tst_hugetlb_fd);
> > +
> > + if (mntpoint_mounted) {
> > + if (tst_test->needs_hugetlbfs)
> > + SAFE_UMOUNT(tst_test->mntpoint);
> > + else
> > + tst_umount(tst_test->mntpoint);
> > + }
>
> Is there a good reason for this, why can't we call tst_umount() for
> hugetlbfs?
>

My reason behind this is,
tst_umount doesnt break the test, if umount fails. One of the cause
of failure can be that test left the mounted fs busy, which is not
expected.
> --
> Cyril Hrubis
> chrubis@suse.cz
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp