[RFC PATCH v4 6/9] KVM: selftests: Add a helper to get system default hugetlb page size
From: Yanan Wang <hidden>
Date: 2021-03-02 15:47:27
Also in:
linux-kselftest, lkml
Subsystem:
kernel selftest framework, kernel virtual machine (kvm), the rest · Maintainers:
Shuah Khan, Paolo Bonzini, Linus Torvalds
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 <redacted> --- .../testing/selftests/kvm/include/test_util.h | 1 + tools/testing/selftests/kvm/lib/test_util.c | 27 +++++++++++++++++++ 2 files changed, 28 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 f2d133f76c67..80d68dbd72d2 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c@@ -153,6 +153,33 @@ 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: %d", errno); + + 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)) { + fclose(f); + TEST_FAIL("HUGETLB is not configured in host kernel"); + } else { + fclose(f); + TEST_FAIL("Error in reading /proc/meminfo: %d", errno); + } + + return 0; +} + void backing_src_help(void) { int i;
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2.23.0