From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57517) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1chCjl-0004CA-8P for qemu-devel@nongnu.org; Fri, 24 Feb 2017 05:04:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1chCjg-0004yw-8K for qemu-devel@nongnu.org; Fri, 24 Feb 2017 05:04:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58638) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1chCjg-0004wO-2A for qemu-devel@nongnu.org; Fri, 24 Feb 2017 05:04:24 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 392ED4DB93 for ; Fri, 24 Feb 2017 10:04:24 +0000 (UTC) Date: Fri, 24 Feb 2017 10:04:19 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20170224100419.GB2435@work-vm> References: <20170206173306.20603-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170206173306.20603-1-dgilbert@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 00/16] Postcopy: Hugepage support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, quintela@redhat.com Cc: lvivier@redhat.com * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > From: "Dr. David Alan Gilbert" > > Hi, > The existing postcopy code, and the userfault kernel > code that supports it, only works for normal anonymous memory. > Kernel support for userfault on hugetlbfs is working > it's way upstream; it's in the linux-mm tree, > You can get a version at: > git://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git > on the origin/userfault branch. This has now merged into Linus's tree as of commit bc49a7831b1137ce1c2dda1c57e3631655f5d2ae on git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Dave > Note that while this code supports arbitrary sized hugepages, > it doesn't make sense with pages above the few-MB region, > so while 2MB is fine, 1GB is probably a bad idea; > this code waits for and transmits whole huge pages, and a > 1GB page would take about 1 second to transfer over a 10Gbps > link - which is way too long to pause the destination for. > > Dave > > Dr. David Alan Gilbert (16): > postcopy: Transmit ram size summary word > postcopy: Transmit and compare individual page sizes > postcopy: Chunk discards for hugepages > exec: ram_block_discard_range > postcopy: enhance ram_block_discard_range for hugepages > Fold postcopy_ram_discard_range into ram_discard_range > postcopy: Record largest page size > postcopy: Plumb pagesize down into place helpers > postcopy: Use temporary for placing zero huge pages > postcopy: Load huge pages in one go > postcopy: Mask fault addresses to huge page boundary > postcopy: Send whole huge pages > postcopy: Allow hugepages > postcopy: Update userfaultfd.h header > postcopy: Check for userfault+hugepage feature > postcopy: Add doc about hugepages and postcopy > > docs/migration.txt | 13 ++++ > exec.c | 83 +++++++++++++++++++++++ > include/exec/cpu-common.h | 2 + > include/exec/memory.h | 1 - > include/migration/migration.h | 3 + > include/migration/postcopy-ram.h | 13 ++-- > linux-headers/linux/userfaultfd.h | 81 +++++++++++++++++++--- > migration/migration.c | 1 + > migration/postcopy-ram.c | 138 +++++++++++++++++--------------------- > migration/ram.c | 109 ++++++++++++++++++------------ > migration/savevm.c | 32 ++++++--- > migration/trace-events | 2 +- > 12 files changed, 328 insertions(+), 150 deletions(-) > > -- > 2.9.3 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK