From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45262) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bcbmN-0001CC-Gs for qemu-devel@nongnu.org; Wed, 24 Aug 2016 13:15:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bcbmH-0000Nz-Cr for qemu-devel@nongnu.org; Wed, 24 Aug 2016 13:15:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12660) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bcbmH-0000Nk-6s for qemu-devel@nongnu.org; Wed, 24 Aug 2016 13:15:49 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (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 ADD954E4D1 for ; Wed, 24 Aug 2016 17:15:48 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" Date: Wed, 24 Aug 2016 18:15:46 +0100 Message-Id: <1472058946-22176-1-git-send-email-dgilbert@redhat.com> Subject: [Qemu-devel] [PATCH] Postcopy vs xbzrle: Don't send xbzrle pages once in postcopy [for 2.8] List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, amit.shah@redhat.com, quintela@redhat.com Cc: mzamazal@redhat.com From: "Dr. David Alan Gilbert" xbzrle relies on reading pages that have already been sent to the destination and then applying the modifications; we can't do that in postcopy because the destination may well have modified the page already or the page has been discarded. I already didn't allow reception of xbzrle pages, but I forgot to add the test to stop them being sent. Enabling both xbzrle and postcopy can make some sense; if you think that your migration might finish if you have xbzrle, then when it doesn't complete you flick over to postcopy and stop xbzrle'ing. This corresponds to RH bug: https://bugzilla.redhat.com/show_bug.cgi?id=1368422 Symptom is: Unknown combination of migration flags: 0x60 (postcopy mode) (either 0x60 or 0x40) Signed-off-by: Dr. David Alan Gilbert --- migration/ram.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index a3d70c4..79fdc94 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -771,7 +771,9 @@ static int ram_save_page(QEMUFile *f, PageSearchStatus *pss, * page would be stale */ xbzrle_cache_zero_page(current_addr); - } else if (!ram_bulk_stage && migrate_use_xbzrle()) { + } else if (!ram_bulk_stage && + !migration_in_postcopy(migrate_get_current()) && + migrate_use_xbzrle()) { pages = save_xbzrle_page(f, &p, current_addr, block, offset, last_stage, bytes_transferred); if (!last_stage) { -- 2.7.4