Since glibc commit 321e1fc73f (“malloc: Enable 2MB THP by default on AArch64”),
glibc may call madvise(MADV_HUGEPAGE) for sufficiently large allocations
made by memalign().
The underlying VMA may start at a different address from the aligned
address returned by memalign(). Furthermore, a subsequent
madvise(MADV_HUGEPAGE) call does not split the VMA because the flag is
already set.
This causes split_huge_page_test to fail because the check_pmd_huge()
helpers incorrectly require the address returned by memalign() to
match the VMA start address reported in /proc/self/smaps.
Instead of relying on /proc/self/smaps, use /proc/self/pagemap and
/proc/kpageflags to detect huge-page mappings checking PAGE_IS_HUGE
and PAGE_IS_FILE accroding to type of huge page.
Since shmem pages are also file-backed, simply check whether the page
is file-backed.
Fixes: 642bc52aed9 ("selftests: vm: bring common functions to a new file")
Suggested-by: David Hildenbrand (Arm) <[email protected]>
Signed-off-by: Yeoreum Yun <[email protected]>
---
tools/testing/selftests/mm/vm_util.c | 78 ++++++++++++++++++++++--------------
1 file changed, 49 insertions(+), 29 deletions(-)
diff --git a/tools/testing/selftests/mm/vm_util.c
b/tools/testing/selftests/mm/vm_util.c
index a0ab78ceedb1..969d7202500c 100644
--- a/tools/testing/selftests/mm/vm_util.c
+++ b/tools/testing/selftests/mm/vm_util.c
@@ -351,24 +351,6 @@ char *__get_smap_entry(void *addr, const char *pattern,
char *buf, size_t len)
return entry;
}
-static bool __check_pmd_huge(void *addr, char *pattern, int nr_hpages,
- uint64_t hpage_size)
-{
- char buffer[MAX_LINE_LENGTH];
- uint64_t thp = -1;
- char *entry;
-
- entry = __get_smap_entry(addr, pattern, buffer, sizeof(buffer));
- if (!entry)
- goto err_out;
-
- if (sscanf(entry, "%9" SCNu64 " kB", &thp) != 1)
- ksft_exit_fail_msg("Reading smap error\n");
-
-err_out:
- return thp == (nr_hpages * (hpage_size >> 10));
-}
-
static bool check_large_folios(void *addr, size_t len, int nr_hpages,
uint64_t hpage_size)
{
@@ -410,20 +392,51 @@ static bool check_large_folios(void *addr, size_t len,
int nr_hpages,
return ret;
}
-bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t
hpage_size)
+enum check_huge_type {
+ CHECK_HUGE_ANON,
+ CHECK_HUGE_FILE,
+};
+
+static bool check_huge_type(uint64_t categories, enum check_huge_type type)
{
- uint64_t pmd_pagesize = read_pmd_pagesize();
+ const bool file = categories & PAGE_IS_FILE;
- if (!pmd_pagesize)
- ksft_exit_fail_msg("reading PMD pagesize failed\n");
+ switch (type) {
+ case CHECK_HUGE_ANON:
+ return !file;
+ case CHECK_HUGE_FILE:
+ return file;
+ }
- if (hpage_size == pmd_pagesize)
- return __check_pmd_huge(addr, "AnonHugePages: ", nr_hpages,
hpage_size);
+ return false;
+}
- return check_large_folios(addr, len, nr_hpages, hpage_size);
+static bool __check_pmd_huge(void *addr, size_t len, int nr_hpages,
+ uint64_t hpage_size, enum check_huge_type type)
+{
+ int pagemap_fd;
+ int nr_pmd_mappings = 0;
+ uint64_t categories;
+ char *start = addr;
+ char *end = start + len;
+
+ pagemap_fd = open(PAGEMAP_PATH, O_RDONLY);
+ if (pagemap_fd < 0)
+ ksft_exit_fail_msg("open pagemap fail\n");
+
+ for (; start < end; start += hpage_size) {
+ categories = pagemap_scan_get_categories(pagemap_fd, start);
+ if (!(categories & PAGE_IS_HUGE))
+ continue;
+ if (check_huge_type(categories, type))
+ nr_pmd_mappings++;
+ }
+ close(pagemap_fd);
+
+ return nr_hpages == nr_pmd_mappings;
}
-bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t
hpage_size)
+bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t
hpage_size)
{
uint64_t pmd_pagesize = read_pmd_pagesize();
@@ -431,12 +444,13 @@ bool check_huge_file(void *addr, size_t len, int
nr_hpages, uint64_t hpage_size)
ksft_exit_fail_msg("reading PMD pagesize failed\n");
if (hpage_size == pmd_pagesize)
- return __check_pmd_huge(addr, "FilePmdMapped:", nr_hpages,
hpage_size);
+ return __check_pmd_huge(addr, len, nr_hpages, hpage_size,
+ CHECK_HUGE_ANON);
return check_large_folios(addr, len, nr_hpages, hpage_size);
}
-bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t
hpage_size)
+bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t
hpage_size)
{
uint64_t pmd_pagesize = read_pmd_pagesize();
@@ -444,11 +458,17 @@ bool check_huge_shmem(void *addr, size_t len, int
nr_hpages, uint64_t hpage_size
ksft_exit_fail_msg("reading PMD pagesize failed\n");
if (hpage_size == pmd_pagesize)
- return __check_pmd_huge(addr, "ShmemPmdMapped:", nr_hpages,
hpage_size);
+ return __check_pmd_huge(addr, len, nr_hpages, hpage_size,
+ CHECK_HUGE_FILE);
return check_large_folios(addr, len, nr_hpages, hpage_size);
}
+bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t
hpage_size)
+{
+ return check_huge_file(addr, len, nr_hpages, hpage_size);
+}
+
int64_t allocate_transhuge(void *ptr, int pagemap_fd)
{
uint64_t ent[2];
--
2.43.0
