From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f199.google.com (mail-yw0-f199.google.com [209.85.161.199]) by kanga.kvack.org (Postfix) with ESMTP id C64336B025E for ; Mon, 18 Apr 2016 06:16:01 -0400 (EDT) Received: by mail-yw0-f199.google.com with SMTP id l137so54654177ywe.0 for ; Mon, 18 Apr 2016 03:16:01 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id q205si46579212qhq.67.2016.04.18.03.16.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Apr 2016 03:16:01 -0700 (PDT) Date: Mon, 18 Apr 2016 11:15:55 +0100 From: "Dr. David Alan Gilbert" Subject: Re: post-copy is broken? Message-ID: <20160418101555.GE2222@work-vm> References: <20160413205132.GG26364@redhat.com> <20160414123441.GF2252@work-vm> <20160414162230.GC9976@redhat.com> <20160415125236.GA3376@node.shutemov.name> <20160415134233.GG2229@work-vm> <20160415152330.GB3376@node.shutemov.name> <20160415163448.GJ2229@work-vm> <20160418095528.GD2222@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: "Li, Liang Z" Cc: "Kirill A. Shutemov" , Andrea Arcangeli , "kirill.shutemov@linux.intel.com" , Amit Shah , "qemu-devel@nongnu.org" , "quintela@redhat.com" , "linux-mm@kvack.org" * Li, Liang Z (liang.z.li@intel.com) wrote: > > * Li, Liang Z (liang.z.li@intel.com) wrote: > > > > > > > I've run it directly, setting relevant QTEST_QEMU_BINARY. > > > > > > > > > > > > Interesting; it's failing reliably for me - but only with a > > > > > > reasonably freshly booted machine (so that the pages get THPd). > > > > > > > > > > The same here. Freshly booted machine with 64GiB ram. I've checked > > > > > /proc/vmstat: huge pages were allocated > > > > > > > > Thanks for testing. > > > > > > > > Damn; this is confusing now. I've got a RHEL7 box with 4.6.0-rc3 on > > > > where it works, and a fedora24 VM where it fails (the f24 VM is > > > > where I did the bisect so it works fine with the older kernel on the f24 > > userspace in that VM). > > > > > > > > So lets see: > > > > works: Kirill's (64GB machine) > > > > Dave's RHEL7 host (24GB RAM, dual xeon, RHEL7 userspace > > > > and kernel > > > > config) > > > > fails: Dave's f24 VM (4GB RAM, 4 vcpus VM on my laptop24 > > > > userspace and kernel config) > > > > > > > > So it's any of userspace, kernel config, machine hardware or hmm. > > > > > > > > My f24 box has transparent_hugepage_madvise, where my rhel7 has > > > > transparent_hugepage_always (but still works if I flip it to madvise > > > > at run time). I'll try and get the configs closer together. > > > > > > > > Liang Li: Can you run my test on your setup which fails the migrate > > > > and tell me what your userspace is? > > > > > > > > (If you've not built my test yet, you might find you need to add a : > > > > tests/postcopy-test$(EXESUF): tests/postcopy-test.o > > > > > > > > to the tests/Makefile) > > > > > > > > > > Hi Dave, > > > > > > How to build and run you test? I didn't do that before. > > > > Apply the code in: > > http://lists.gnu.org/archive/html/qemu-devel/2016-04/msg02138.html > > > > fix the: > > + if ( ((b + 1) % 255) == last_byte && !hit_edge) { > > to: > > + if ( ((b + 1) % 256) == last_byte && !hit_edge) { > > > > to tests/Makefile > > tests/postcopy-test$(EXESUF): tests/postcopy-test.o > > > > and do a: > > make check > > > > in qemu. > > Then you can rerun the test with: > > QTEST_QEMU_BINARY=path/to/qemu-system-x86_64 ./tests/postcopy- > > test > > > > if it works, reboot and check it still works from a fresh boot. > > > > Can you describe the system which your full test failed on? What distro on > > the host? What type of host was it tested on? > > > > Dave > > > > > Thanks, Dave > > The host is CenOS7, its original kernel is 3.10.0-327.el7.x86_64 (CentOS 7.1?), > The hardware platform is HSW-EP with 64GB RAM. OK, so your test fails on real hardware; my guess is that my test will work on there. Can you try your test with THP disabled on the host: echo never > /sys/kernel/mm/transparent_hugepage/enabled Dave > > > > > > > > Thanks! > > > Liang > > > > > > > > > > > Dave > > > > > > > > > > -- > > > > > Kirill A. Shutemov > > > > -- > > > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > -- > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org