From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49861) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1brj28-0006sS-FO for qemu-devel@nongnu.org; Wed, 05 Oct 2016 06:02:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1brj23-0007Dt-Fs for qemu-devel@nongnu.org; Wed, 05 Oct 2016 06:02:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37228) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1brj23-0007Dp-9Y for qemu-devel@nongnu.org; Wed, 05 Oct 2016 06:02:35 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (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 BBFD06365E for ; Wed, 5 Oct 2016 10:02:34 +0000 (UTC) From: Juan Quintela In-Reply-To: <20160930080944.GB17928@redhat.com> (Daniel P. Berrange's message of "Fri, 30 Sep 2016 09:09:44 +0100") References: <1475176178-4873-1-git-send-email-dgilbert@redhat.com> <1475176178-4873-3-git-send-email-dgilbert@redhat.com> <20160930080944.GB17928@redhat.com> Reply-To: quintela@redhat.com Date: Wed, 05 Oct 2016 12:02:30 +0200 Message-ID: <87shsbqfk9.fsf@emacs.mitica> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH 2/2] migration/postcopy: Explicitly disallow huge pages List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: "Dr. David Alan Gilbert (git)" , qemu-devel@nongnu.org, pbonzini@redhat.com, amit.shah@redhat.com "Daniel P. Berrange" wrote: > On Thu, Sep 29, 2016 at 08:09:38PM +0100, Dr. David Alan Gilbert (git) wrote: >> From: "Dr. David Alan Gilbert" >> >> At the moment postcopy will fail as soon as qemu tries to register >> userfault on the RAMBlock pages that are backed by hugepages. >> However, the kernel is going to get userfault support for hugepage >> at some point, and we've not got the rest of the QEMU code to support >> it yet, so fail neatly with an error like: >> >> Postcopy doesn't support hugetlbfs yet (/objects/mem1) >> >> Signed-off-by: Dr. David Alan Gilbert >> --- >> migration/postcopy-ram.c | 23 +++++++++++++++++++++++ >> 1 file changed, 23 insertions(+) >> >> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c >> index 9b04778..9723593 100644 >> --- a/migration/postcopy-ram.c >> +++ b/migration/postcopy-ram.c >> @@ -85,6 +85,23 @@ static bool ufd_version_check(int ufd) >> } >> >> /* >> + * Check for things that postcopy won't support; returns 0 if the block >> + * is fine. >> + */ >> +static int check_range(const char *block_name, void *host_addr, >> + ram_addr_t offset, ram_addr_t length, void *opaque) >> +{ >> + RAMBlock *rb = qemu_ram_block_by_name(block_name); >> + >> + if (qemu_ram_pagesize(rb) > getpagesize()) { >> + error_report("Postcopy doesn't support hugetlbfs yet (%s)", block_name); > > A small nitpick - I'd suggest s/hugetlbfs/large page sizes/ as this error > will ultimately bubble up to users, and 'large page sizes' is the conceptual > feature Reviewed-by: Juan Quintela I fixed the message my hand