diff mbox series

[V2,5/6] KVM: selftests: Add get_free_huge_2m_pages

Message ID 20221205232341.4131240-6-vannapurve@google.com
State New
Headers
Series KVM: selftests: selftests for fd-based private memory |

Commit Message

Vishal Annapurve Dec. 5, 2022, 11:23 p.m. UTC 
  Add an API to query free 2MB hugepages in the system.

Signed-off-by: Vishal Annapurve <vannapurve@google.com>
---
 .../testing/selftests/kvm/include/test_util.h  |  1 +
 tools/testing/selftests/kvm/lib/test_util.c    | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

Comments

Sean Christopherson Jan. 17, 2023, 10:12 p.m. UTC | #1 
On Mon, Dec 05, 2022, Vishal Annapurve wrote:
> Add an API to query free 2MB hugepages in the system.
> 
> Signed-off-by: Vishal Annapurve <vannapurve@google.com>
> ---
>  .../testing/selftests/kvm/include/test_util.h  |  1 +
>  tools/testing/selftests/kvm/lib/test_util.c    | 18 ++++++++++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
> index aea80071f2b8..3d1cc215940a 100644
> --- a/tools/testing/selftests/kvm/include/test_util.h
> +++ b/tools/testing/selftests/kvm/include/test_util.h
> @@ -122,6 +122,7 @@ struct vm_mem_backing_src_alias {
>  bool thp_configured(void);
>  size_t get_trans_hugepagesz(void);
>  size_t get_def_hugetlb_pagesz(void);
> +size_t get_free_huge_2mb_pages(void);
>  const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i);
>  size_t get_backing_src_pagesz(uint32_t i);
>  bool is_backing_src_hugetlb(uint32_t i);
> diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
> index d33b98bfe8a3..745573023b57 100644
> --- a/tools/testing/selftests/kvm/lib/test_util.c
> +++ b/tools/testing/selftests/kvm/lib/test_util.c
> @@ -162,6 +162,24 @@ size_t get_trans_hugepagesz(void)
>  	return size;
>  }
>  
> +size_t get_free_huge_2mb_pages(void)

I strongly prefer to follow the precedence set by other tests, which at this
point means defaulting to non-huge pages.  I do think we need to make it easier
and/or automatic to test hugepages, but I would like to tackle that problem
separately.  E.g. a kernel built without hugepage support will fail the fopen()
below.

> +{
> +	size_t free_pages;
> +	FILE *f;
> +	int ret;
> +
> +	f = fopen("/sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages", "r");
> +	TEST_ASSERT(f != NULL, "Error in opening hugepages-2048kB/free_hugepages");
> +
> +	do {
> +		ret = fscanf(f, "%ld", &free_pages);
> +	} while (errno == EINTR);
> +	TEST_ASSERT(ret < 1, "Error reading hugepages-2048kB/free_hugepages");
> +	fclose(f);
> +
> +	return free_pages;
> +}
> +
>  size_t get_def_hugetlb_pagesz(void)
>  {
>  	char buf[64];
> -- 
> 2.39.0.rc0.267.gcb52ba06e7-goog
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index aea80071f2b8..3d1cc215940a 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -122,6 +122,7 @@  struct vm_mem_backing_src_alias {
 bool thp_configured(void);
 size_t get_trans_hugepagesz(void);
 size_t get_def_hugetlb_pagesz(void);
+size_t get_free_huge_2mb_pages(void);
 const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i);
 size_t get_backing_src_pagesz(uint32_t i);
 bool is_backing_src_hugetlb(uint32_t i);
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index d33b98bfe8a3..745573023b57 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -162,6 +162,24 @@  size_t get_trans_hugepagesz(void)
 	return size;
 }
 
+size_t get_free_huge_2mb_pages(void)
+{
+	size_t free_pages;
+	FILE *f;
+	int ret;
+
+	f = fopen("/sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages", "r");
+	TEST_ASSERT(f != NULL, "Error in opening hugepages-2048kB/free_hugepages");
+
+	do {
+		ret = fscanf(f, "%ld", &free_pages);
+	} while (errno == EINTR);
+	TEST_ASSERT(ret < 1, "Error reading hugepages-2048kB/free_hugepages");
+	fclose(f);
+
+	return free_pages;
+}
+
 size_t get_def_hugetlb_pagesz(void)
 {
 	char buf[64];