From 8b8b5f4749f65221dd88579638971b68b8e880e9 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Wed, 19 Oct 2016 20:43:48 +0200 Subject: [PATCH 5/6] Postcopy vs xbzrle: Don't send xbzrle pages once in postcopy [for 2.8] RH-Author: Dr. David Alan Gilbert Message-id: <20161019144348.14520-2-dgilbert@redhat.com> Patchwork-id: 72613 O-Subject: [RHEL-7.4/7.3.z qemu-kvm-rhev PATCH 1/1] Postcopy vs xbzrle: Don't send xbzrle pages once in postcopy [for 2.8] Bugzilla: 1395360 RH-Acked-by: John Snow RH-Acked-by: Juan Quintela RH-Acked-by: Laurent Vivier 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. Symptom is: Unknown combination of migration flags: 0x60 (postcopy mode) (either 0x60 or 0x40) Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela (cherry picked from commit 2ebeaec012b4e5695612774c44f14c61ab46c72c) Signed-off-by: Miroslav Rezanina --- migration/ram.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index 96faa74..7b98266 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -774,7 +774,9 @@ 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) { -- 1.8.3.1