linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] SelfTest: KVM: Drop Asserts for madvise failures
@ 2018-11-15 18:09 Ahmed Abd El Mawgood
  2018-11-16  9:11 ` Andrew Jones
  0 siblings, 1 reply; 2+ messages in thread
From: Ahmed Abd El Mawgood @ 2018-11-15 18:09 UTC (permalink / raw)
  To: Shuah Khan, Paolo Bonzini, Andrew Jones, Peter Xu,
	Colin Ian King, linux-kselftest, linux-kernel, Hossam Hassan,
	Ahmed Lotfy, Vitaly Kuznetsov, Anders Roxell
  Cc: Ahmed Abd El Mawgood

From: Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>

madvise() returns -1 without CONFIG_TRANSPARENT_HUGEPAGE=y. That would
trigger asserts when checking for return value of madvice. Following
similar decision to [1]. I thought it is ok to assume that madvise()
failures implies that THP is not supported by host kernel.

Other options were to check for Transparent Huge Page support in
/sys/kernel/mm/transparent_hugepage/enabled.

-- links --
[1] https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg04514.html

Signed-off-by: Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 1b41e71283d5..7725cfdf1b79 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -586,14 +586,12 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 				 src_type == VM_MEM_SRC_ANONYMOUS_THP ?  huge_page_size : 1);
 
 	/* As needed perform madvise */
-	if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {
-		ret = madvise(region->host_mem, npages * vm->page_size,
-			     src_type == VM_MEM_SRC_ANONYMOUS ? MADV_NOHUGEPAGE : MADV_HUGEPAGE);
-		TEST_ASSERT(ret == 0, "madvise failed,\n"
-			    "  addr: %p\n"
-			    "  length: 0x%lx\n"
-			    "  src_type: %x",
-			    region->host_mem, npages * vm->page_size, src_type);
+	if (src_type == VM_MEM_SRC_ANONYMOUS) {
+		madvise(region->host_mem, npages * vm->page_size,
+				MADV_NOHUGEPAGE);
+	} else if (src_type == VM_MEM_SRC_ANONYMOUS_THP) {
+		madvise(region->host_mem, npages * vm->page_size,
+				MADV_HUGEPAGE);
 	}
 
 	region->unused_phy_pages = sparsebit_alloc();
-- 
2.18.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] SelfTest: KVM: Drop Asserts for madvise failures
  2018-11-15 18:09 [PATCH] SelfTest: KVM: Drop Asserts for madvise failures Ahmed Abd El Mawgood
@ 2018-11-16  9:11 ` Andrew Jones
  0 siblings, 0 replies; 2+ messages in thread
From: Andrew Jones @ 2018-11-16  9:11 UTC (permalink / raw)
  To: Ahmed Abd El Mawgood
  Cc: Shuah Khan, Paolo Bonzini, Peter Xu, Colin Ian King,
	linux-kselftest, linux-kernel, Hossam Hassan, Ahmed Lotfy,
	Vitaly Kuznetsov, Anders Roxell

On Thu, Nov 15, 2018 at 08:09:07PM +0200, Ahmed Abd El Mawgood wrote:
> From: Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>
> 
> madvise() returns -1 without CONFIG_TRANSPARENT_HUGEPAGE=y. That would
> trigger asserts when checking for return value of madvice. Following
> similar decision to [1]. I thought it is ok to assume that madvise()
> failures implies that THP is not supported by host kernel.
> 
> Other options were to check for Transparent Huge Page support in
> /sys/kernel/mm/transparent_hugepage/enabled.
> 
> -- links --
> [1] https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg04514.html
> 
> Signed-off-by: Ahmed Abd El Mawgood <ahmedsoliman@mena.vt.edu>
> ---
>  tools/testing/selftests/kvm/lib/kvm_util.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 1b41e71283d5..7725cfdf1b79 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -586,14 +586,12 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
>  				 src_type == VM_MEM_SRC_ANONYMOUS_THP ?  huge_page_size : 1);
>  
>  	/* As needed perform madvise */
> -	if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {
> -		ret = madvise(region->host_mem, npages * vm->page_size,
> -			     src_type == VM_MEM_SRC_ANONYMOUS ? MADV_NOHUGEPAGE : MADV_HUGEPAGE);
> -		TEST_ASSERT(ret == 0, "madvise failed,\n"
> -			    "  addr: %p\n"
> -			    "  length: 0x%lx\n"
> -			    "  src_type: %x",
> -			    region->host_mem, npages * vm->page_size, src_type);
> +	if (src_type == VM_MEM_SRC_ANONYMOUS) {
> +		madvise(region->host_mem, npages * vm->page_size,
> +				MADV_NOHUGEPAGE);

This is fine.

> +	} else if (src_type == VM_MEM_SRC_ANONYMOUS_THP) {
> +		madvise(region->host_mem, npages * vm->page_size,
> +				MADV_HUGEPAGE);

I would still assert here, but with a more informative message like
"madvise(MADV_HUGEPAGE) failed. Does the kernel have
CONFIG_TRANSPARENT_HUGEPAGE=y?"

>  	}
>  
>  	region->unused_phy_pages = sparsebit_alloc();
> -- 
> 2.18.1
> 

Thanks,
drew

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2018-11-16  9:11 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-15 18:09 [PATCH] SelfTest: KVM: Drop Asserts for madvise failures Ahmed Abd El Mawgood
2018-11-16  9:11 ` Andrew Jones

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).