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    SubjectRe: [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 <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()
    > 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 <ahmedsoliman@mena.vt.edu>
    > ---
    > 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 <drjones@redhat.com>

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