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

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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>
Message-Id: <20210330080856.14940-8-wangyanan55@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Yanan Wang 2021-03-30 16:08:53 +08:00 committed by Paolo Bonzini
parent 3b70c4d128
commit 5579fa682a
2 changed files with 26 additions and 0 deletions
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1
tools/testing/selftests/kvm/include/test_util.h
View File

@ -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);

25
tools/testing/selftests/kvm/lib/test_util.c
View File

@ -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;