2018-11-16 11:52:27

by Ahmed Abd El Mawgood

Subject: [PATCH V2] SelfTest: KVM: Drop Asserts for madvise MADV_NOHUGEPAGE failure

From: Ahmed Abd El Mawgood <[email protected]>

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()
MADV_NOHUGEPAGE failures implies that THP is not supported by host kernel.

Other options was 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 <[email protected]>
---
tools/testing/selftests/kvm/lib/kvm_util.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 1b41e71283d5..437c5bb48061 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -586,14 +586,23 @@ 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) {
+ if (src_type == VM_MEM_SRC_ANONYMOUS) {
+ /*
+ * Neglect madvise error because it is ok to not have THP
+ * support in this case.
+ */
+ madvise(region->host_mem, npages * vm->page_size,
+ MADV_NOHUGEPAGE);
+ } else if (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);
+ 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);
+ "Does the kernel have CONFIG_TRANSPARENT_HUGEPAGE=y\n"
+ " addr: %p\n"
+ " length: 0x%lx\n"
+ " src_type: %x\n",
+ region->host_mem, npages * vm->page_size,
+ src_type);
}

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

2018-11-16 13:00:01

by Andrew Jones

Subject: Re: [PATCH V2] SelfTest: KVM: Drop Asserts for madvise MADV_NOHUGEPAGE failure

On Fri, Nov 16, 2018 at 01:50:55PM +0200, Ahmed Abd El Mawgood wrote:
> From: Ahmed Abd El Mawgood <[email protected]>
>
> 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()
> MADV_NOHUGEPAGE failures implies that THP is not supported by host kernel.
>
> Other options was 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 <[email protected]>
> ---
> tools/testing/selftests/kvm/lib/kvm_util.c | 21 +++++++++++++++------
> 1 file changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 1b41e71283d5..437c5bb48061 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -586,14 +586,23 @@ 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) {
> + if (src_type == VM_MEM_SRC_ANONYMOUS) {
> + /*
> + * Neglect madvise error because it is ok to not have THP
> + * support in this case.
> + */
> + madvise(region->host_mem, npages * vm->page_size,
> + MADV_NOHUGEPAGE);
> + } else if (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);
> + 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);
> + "Does the kernel have CONFIG_TRANSPARENT_HUGEPAGE=y\n"
> + " addr: %p\n"
> + " length: 0x%lx\n"
> + " src_type: %x\n",
> + region->host_mem, npages * vm->page_size,
> + src_type);
> }
>
> region->unused_phy_pages = sparsebit_alloc();
> --
> 2.18.1
>

Reviewed-by: Andrew Jones <[email protected]>

2018-12-24 14:59:01

by Ahmed Abd El Mawgood

Subject: Re: [PATCH V2] SelfTest: KVM: Drop Asserts for madvise MADV_NOHUGEPAGE failure

Kind reminder to merge my patch into next

thanks.

On Fri, Nov 16, 2018 at 2:59 PM Andrew Jones <[email protected]> wrote:
>
> On Fri, Nov 16, 2018 at 01:50:55PM +0200, Ahmed Abd El Mawgood wrote:
> > From: Ahmed Abd El Mawgood <[email protected]>
> >
> > 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()
> > MADV_NOHUGEPAGE failures implies that THP is not supported by host kernel.
> >
> > Other options was 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 <[email protected]>
> > ---
> > tools/testing/selftests/kvm/lib/kvm_util.c | 21 +++++++++++++++------
> > 1 file changed, 15 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> > index 1b41e71283d5..437c5bb48061 100644
> > --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> > @@ -586,14 +586,23 @@ 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) {
> > + if (src_type == VM_MEM_SRC_ANONYMOUS) {
> > + /*
> > + * Neglect madvise error because it is ok to not have THP
> > + * support in this case.
> > + */
> > + madvise(region->host_mem, npages * vm->page_size,
> > + MADV_NOHUGEPAGE);
> > + } else if (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);
> > + 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);
> > + "Does the kernel have CONFIG_TRANSPARENT_HUGEPAGE=y\n"
> > + " addr: %p\n"
> > + " length: 0x%lx\n"
> > + " src_type: %x\n",
> > + region->host_mem, npages * vm->page_size,
> > + src_type);
> > }
> >
> > region->unused_phy_pages = sparsebit_alloc();
> > --
> > 2.18.1
> >
>
> Reviewed-by: Andrew Jones <[email protected]>



--
Junior Researcher, IoT and Cyber Security lab, SmartCI, Alexandria
University, & CIS @ VMI

2018-12-27 14:35:15

by Shuah Khan

Subject: Re: [PATCH V2] SelfTest: KVM: Drop Asserts for madvise MADV_NOHUGEPAGE failure

Hi Paolo,

On 12/24/18 7:56 AM, Ahmed Soliman wrote:
> Kind reminder to merge my patch into next
>
> thanks.
>

I am assuming you will be picking this patch up. Please let me know if
you want me to take it through kselftest tree.

thanks,
-- Shuah

2019-01-07 23:35:28

by Paolo Bonzini

Subject: Re: [PATCH V2] SelfTest: KVM: Drop Asserts for madvise MADV_NOHUGEPAGE failure

On 27/12/18 01:44, shuah wrote:
> Hi Paolo,
>
> On 12/24/18 7:56 AM, Ahmed Soliman wrote:
>> Kind reminder to merge my patch into next
>>
>> thanks.
>>
>
> I am assuming you will be picking this patch up. Please let me know if
> you want me to take it through kselftest tree.

Yes, I was on vacataion but I'm back now.

Paolo