Eric,
Please forgive me for this extremely late reply, but I believe that the
introduction and use of get_mapping_page_size() has introduced some regressions
in the libhugetlbfs test suite, particularly on SLES11.
The SLES11 release is based on kernel 2.6.27. In this version of the kernel,
/proc/self/smaps does not include a "KernelPageSize" field. In this case,
get_mapping_size() returns 0. This causes several tests to (incorrectly) fail,
as they believe that the pages are not mapped by hugepages.
I would like to offer some suggestions:
- If there is no "KernelPageSize" field, get_mapping_size() should return -1 to
indicate that no page size could be determined.
- Callers of get_mapping_size() should use PASS_INCONCLUSIVE() if no page size
can be determined.
- A few tests (e.g., heapshrink, malloc, malloc_manysmall) do not care what the
actual hugepage size is; they should use test_addr_huge() instead.
- test_addr_huge() should be generalized to use get_mapping_size() if
appropriate (based on the kernel version?).
Best regards,
-Andrew Hastings
Cray Inc.
On 11/23/2010 09:52 AM Eric B Munson wrote:
> When MAP_HUGETLB is used, the standard test for a mapping being backed by huge
> pages fails because the mapping will not be on hugetlbfs. Instead of testing
> the filesystem backing the mapping, this patch adds a check of reported MMU
> page size from /proc/self/smaps. get_mapping_page_size returns the page
> size that is being used for the specified mapping in bytes.
>
> Signed-off-by: Eric B Munson <emun...@mgebm.net>
> ---
> tests/hugetests.h | 1 +
> tests/testutils.c | 54
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+), 0 deletions(-)
>
> diff --git a/tests/hugetests.h b/tests/hugetests.h
> index 85f5b4f..a5a54d6 100644
> --- a/tests/hugetests.h
> +++ b/tests/hugetests.h
> @@ -45,6 +45,7 @@ void check_must_be_root(void);
> void check_hugetlb_shm_group(void);
> void test_init(int argc, char *argv[]);
> int test_addr_huge(void *p);
> +unsigned long long get_mapping_page_size(void *p);
> long read_meminfo(const char *tag);
> ino_t get_addr_inode(void *p);
>
> diff --git a/tests/testutils.c b/tests/testutils.c
> index b8a1bf2..68d8e62 100644
> --- a/tests/testutils.c
> +++ b/tests/testutils.c
> @@ -162,6 +162,60 @@ static int read_maps(unsigned long addr, char *buf)
> return 0;
> }
>
> +/*
> + * With the inclusion of MAP_HUGETLB it is now possible to have huge pages
> + * without using hugetlbfs, so not all huge page regions will show with the
> + * test that reads /proc/self/maps. Instead we ask /proc/self/smaps for
> + * the KernelPageSize. On success we return the page size (in bytes) for the
> + * mapping that contains addr, on failure we return 0
> + */
> +unsigned long long get_mapping_page_size(void *p)
> +{
> + FILE *f;
> + char line[MAPS_BUF_SZ];
> + char *tmp;
> + unsigned long addr = (unsigned long)p;
> +
> + f = fopen("/proc/self/smaps", "r");
> + if (!f) {
> + ERROR("Unable to open /proc/self/smaps\n");
> + return 0;
> + }
> +
> + while ((tmp = fgets(line, MAPS_BUF_SZ, f))) {
> + unsigned long start, end, dummy;
> + char map_name[256];
> + char buf[64];
> + int ret;
> +
> + ret = sscanf(line, "%lx-%lx %s %lx %s %ld %s", &start, &end,
> + buf, &dummy, buf, &dummy, map_name);
> + if (ret < 7 || start > addr || end <= addr)
> + continue;
> +
> + while ((tmp = fgets(line, MAPS_BUF_SZ, f))) {
> + unsigned long long page_size;
> +
> + ret = sscanf(line, "KernelPageSize: %lld kB",
> + &page_size);
> + if (ret == 0 )
> + continue;
> + if (ret < 1 || page_size <= 0) {
> + ERROR("Cannot parse /proc/self/smaps\n");
> + page_size = 0;
> + }
> +
> + fclose(f);
> + /* page_size is reported in kB, we return B */
> + return page_size * 1024;
> + }
> + }
> +
> + /* We couldn't find an entry for this addr in smaps */
> + fclose(f);
> + return 0;
> +}
> +
> /* We define this function standalone, rather than in terms of
> * hugetlbfs_test_path() so that we can use it without -lhugetlbfs for
> * testing PRELOAD */
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