If HUGETLB is configured in the host kernel, then we can know the system default hugetlb page size through *cat /proc/meminfo*. Otherwise, we will not see the information of hugetlb pages in file /proc/meminfo if it's not configured. So add a helper to determine whether HUGETLB is configured and then get the default page size by reading /proc/meminfo.
This helper can be useful when a program wants to use the default hugetlb pages of the system and doesn't know the default page size.
Signed-off-by: Yanan Wang wangyanan55@huawei.com Reviewed-by: Andrew Jones drjones@redhat.com --- .../testing/selftests/kvm/include/test_util.h | 1 + tools/testing/selftests/kvm/lib/test_util.c | 25 +++++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index ef24c76ba89a..e087174eefe5 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -80,6 +80,7 @@ struct vm_mem_backing_src_alias {
bool thp_configured(void); size_t get_trans_hugepagesz(void); +size_t get_def_hugetlb_pagesz(void); void backing_src_help(void); enum vm_mem_backing_src_type parse_backing_src_type(const char *type_name);
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index efc1a7782de0..665724ccab97 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -146,6 +146,31 @@ size_t get_trans_hugepagesz(void) return size; }
+size_t get_def_hugetlb_pagesz(void) +{ + char buf[64]; + const char *tag = "Hugepagesize:"; + FILE *f; + + f = fopen("/proc/meminfo", "r"); + TEST_ASSERT(f != NULL, "Error in opening /proc/meminfo"); + + while (fgets(buf, sizeof(buf), f) != NULL) { + if (strstr(buf, tag) == buf) { + fclose(f); + return strtoull(buf + strlen(tag), NULL, 10) << 10; + } + } + + if (feof(f)) + TEST_FAIL("HUGETLB is not configured in host kernel"); + else + TEST_FAIL("Error in reading /proc/meminfo"); + + fclose(f); + return 0; +} + void backing_src_help(void) { int i;