From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 8D89A6B007E for ; Mon, 18 Apr 2016 06:33:18 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id e190so320910158pfe.3 for ; Mon, 18 Apr 2016 03:33:18 -0700 (PDT) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTP id n8si7231823pac.162.2016.04.18.03.33.17 for ; Mon, 18 Apr 2016 03:33:17 -0700 (PDT) From: "Li, Liang Z" Subject: RE: post-copy is broken? Date: Mon, 18 Apr 2016 10:33:14 +0000 Message-ID: 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> <20160418101555.GE2222@work-vm> In-Reply-To: <20160418101555.GE2222@work-vm> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "Dr. David Alan Gilbert" Cc: "Kirill A. Shutemov" , Andrea Arcangeli , "kirill.shutemov@linux.intel.com" , Amit Shah , "qemu-devel@nongnu.org" , "quintela@redhat.com" , "linux-mm@kvack.org" > > > > > > > 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 togeth= er. > > > > > > > > > > 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$(EXESUF): tests/postcopy-test.o > > > > > > > > > > to the tests/Makefile) > > > > > > > > > > > > > Hi Dave, > > > > > > > > How to build and run you test? I didn't do that before. > > > > > > Apply the code in: > > > http://lists.gnu.org/archive/html/qemu-devel/2016-04/msg02138.html > > > > > > fix the: > > > + if ( ((b + 1) % 255) =3D=3D last_byte && !hit_edge) { > > > to: > > > + if ( ((b + 1) % 256) =3D=3D last_byte && !hit_edge) { > > > > > > to tests/Makefile > > > tests/postcopy-test$(EXESUF): tests/postcopy-test.o > > > > > > and do a: > > > make check > > > > > > in qemu. > > > Then you can rerun the test with: > > > QTEST_QEMU_BINARY=3Dpath/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. >=20 > OK, so your test fails on real hardware; my guess is that my test will wo= rk on > there. > Can you try your test with THP disabled on the host: >=20 > echo never > /sys/kernel/mm/transparent_hugepage/enabled >=20 If the THP is disabled, no fails. And your test was always passed, even when real post-copy was failed.=20 In my env, the output of=20 'cat /sys/kernel/mm/transparent_hugepage/enabled' is: [always] ... Liang > Dave >=20 > > > > > > > > > > > > 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