Commit 5579fa68 authored by Yanan Wang's avatar Yanan Wang Committed by Paolo Bonzini
Browse files

KVM: selftests: Add a helper to get system default hugetlb page size 



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: default avatarYanan Wang <wangyanan55@huawei.com>
Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
Message-Id: <20210330080856.14940-8-wangyanan55@huawei.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3b70c4d1

tools/testing/selftests/kvm/include/test_util.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

tools/testing/selftests/kvm/lib/test_util.c

+25 −0
Original line number Diff line number Diff line
@@ -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;