Messages in this thread | | | Subject | Re: [PATCH] hugetlb_cgroup: fix reservation accounting | From | Michal Privoznik <> | Date | Thu, 22 Oct 2020 09:42:47 +0200 |
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On 10/21/20 10:44 PM, Mike Kravetz wrote: > Michal Privoznik was using "free page reporting" in QEMU/virtio-balloon > with hugetlbfs and hit the warning below. QEMU with free page hinting > uses fallocate(FALLOC_FL_PUNCH_HOLE) to discard pages that are reported > as free by a VM. The reporting granularity is in pageblock granularity. > So when the guest reports 2M chunks, we fallocate(FALLOC_FL_PUNCH_HOLE) > one huge page in QEMU. > > [ 315.251417] ------------[ cut here ]------------ > [ 315.251424] WARNING: CPU: 7 PID: 6636 at mm/page_counter.c:57 page_counter_uncharge+0x4b/0x50 > [ 315.251425] Modules linked in: ... > [ 315.251466] CPU: 7 PID: 6636 Comm: qemu-system-x86 Not tainted 5.9.0 #137 > [ 315.251467] Hardware name: Gigabyte Technology Co., Ltd. X570 AORUS PRO/X570 AORUS PRO, BIOS F21 07/31/2020 > [ 315.251469] RIP: 0010:page_counter_uncharge+0x4b/0x50 > ... > [ 315.251479] Call Trace: > [ 315.251485] hugetlb_cgroup_uncharge_file_region+0x4b/0x80 > [ 315.251487] region_del+0x1d3/0x300 > [ 315.251489] hugetlb_unreserve_pages+0x39/0xb0 > [ 315.251492] remove_inode_hugepages+0x1a8/0x3d0 > [ 315.251495] ? tlb_finish_mmu+0x7a/0x1d0 > [ 315.251497] hugetlbfs_fallocate+0x3c4/0x5c0 > [ 315.251519] ? kvm_arch_vcpu_ioctl_run+0x614/0x1700 [kvm] > [ 315.251522] ? file_has_perm+0xa2/0xb0 > [ 315.251524] ? inode_security+0xc/0x60 > [ 315.251525] ? selinux_file_permission+0x4e/0x120 > [ 315.251527] vfs_fallocate+0x146/0x290 > [ 315.251529] __x64_sys_fallocate+0x3e/0x70 > [ 315.251531] do_syscall_64+0x33/0x40 > [ 315.251533] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > ... > [ 315.251542] ---[ end trace 4c88c62ccb1349c9 ]--- > > Investigation of the issue uncovered bugs in hugetlb cgroup reservation > accounting. This patch addresses the found issues. > > Fixes: 075a61d07a8e ("hugetlb_cgroup: add accounting for shared mappings") > Cc: <stable@vger.kernel.org> > Reported-by: Michal Privoznik <mprivozn@redhat.com> > Co-developed-by: David Hildenbrand <david@redhat.com> > Signed-off-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> > --- > mm/hugetlb.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-)
I just tested this and can confirm it fixes the problem:
Tested-by: Michal Privoznik <mprivozn@redhat.com>
Thank you! Michal
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