Hi Gerald, On Tue, Nov 08, 2016 at 03:08:52PM +0800, Huang Shijie wrote: > On Tue, Nov 08, 2016 at 10:19:30AM +0800, Huang Shijie wrote: > > On Mon, Nov 07, 2016 at 04:25:04PM +0100, Gerald Schaefer wrote: > > > On Thu, 3 Nov 2016 10:51:38 +0800 > > > Huang Shijie <shijie.huang@xxxxxxx> wrote: > > > > > > > When testing the gigantic page whose order is too large for the buddy > > > > allocator, the libhugetlbfs test case "counter.sh" will fail. > > > > > > > > The failure is caused by: > > > > 1) kernel fails to allocate a gigantic page for the surplus case. > > > > And the gather_surplus_pages() will return NULL in the end. > > > > > > > > 2) The condition checks for "over-commit" is wrong. > > > > > > > > This patch adds code to allocate the gigantic page in the > > > > __alloc_huge_page(). After this patch, gather_surplus_pages() > > > > can return a gigantic page for the surplus case. > > > > > > > > This patch also changes the condition checks for: > > > > return_unused_surplus_pages() > > > > nr_overcommit_hugepages_store() > > > > > > > > After this patch, the counter.sh can pass for the gigantic page. > > > > > > > > Acked-by: Steve Capper <steve.capper@xxxxxxx> > > > > Signed-off-by: Huang Shijie <shijie.huang@xxxxxxx> > > > > --- > > > > mm/hugetlb.c | 15 ++++++++++----- > > > > 1 file changed, 10 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > > > index 0bf4444..2b67aff 100644 > > > > --- a/mm/hugetlb.c > > > > +++ b/mm/hugetlb.c > > > > @@ -1574,7 +1574,7 @@ static struct page *__alloc_huge_page(struct hstate *h, > > > > struct page *page; > > > > unsigned int r_nid; > > > > > > > > - if (hstate_is_gigantic(h)) > > > > + if (hstate_is_gigantic(h) && !gigantic_page_supported()) > > > > return NULL; > > > > > > Is it really possible to stumble over gigantic pages w/o having > > > gigantic_page_supported()? > > > > > > Also, I've just tried this on s390 and counter.sh still fails after these > > > patches, and it should fail on all archs as long as you use the gigantic > > I guess the failure you met is caused by the libhugetlbfs itself, there are > > several bugs in the libhugetlbfs. I have a patch set for the > > libhugetlbfs too. I will send it as soon as possible. > > > > > hugepage size as default hugepage size. This is because you only changed > > > nr_overcommit_hugepages_store(), which handles nr_overcommit_hugepages > > > in sysfs, and missed hugetlb_overcommit_handler() which handles > > > /proc/sys/vm/nr_overcommit_hugepages for the default sized hugepages. > > This is wrong. :) > Sorry, I was wrong :). The counters test does call the /proc/sys/vm/nr_overcommit_hugepages. > But in the arm64, it does not trigger a fail for the counters test. > In an other word, I did not change the hugetlb_overcommit_handler(), > the counters.sh also can pass in arm64. After I add the "default_hugepagesz=32M" to the kernel cmdlin, I can reproduce this issue. Thanks for point this. > > I will look at the lockdep issue. I tested the new patch (will be sent out later) on the arm64 platform, and I did not meet the lockdep issue when I enabled the lockdep. The following is my config: CONFIG_LOCKD=y CONFIG_LOCKD_V4=y CONFIG_LOCKUP_DETECTOR=y # CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE=0 CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_LOCKDEP=y CONFIG_LOCK_STAT=y CONFIG_DEBUG_LOCKDEP=y CONFIG_DEBUG_LOCKING_API_SELFTESTS=y So do I miss something? Thanks Huang Shijie -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>