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From: Peter Lieven <pl@kamp.de>
To: qemu-devel@nongnu.org
Cc: quintela@redhat.com, aik@ozlabs.ru, Peter Lieven <pl@kamp.de>,
	owasserm@redhat.com, pbonzini@redhat.com,
	xiawenc@linux.vnet.ibm.com, david@gibson.dropbear.id.au
Subject: [Qemu-devel] [PATCHv2 1/2] Revert "migration: do not sent zero pages in bulk stage"
Date: Mon, 10 Jun 2013 12:14:19 +0200	[thread overview]
Message-ID: <1370859260-8183-2-git-send-email-pl@kamp.de> (raw)
In-Reply-To: <1370859260-8183-1-git-send-email-pl@kamp.de>

Not sending zero pages breaks migration if a page is zero
at the source but not at the destination. This can e.g. happen
if different BIOS versions are used at source and destination.
It has also been reported that migration on pseries is completely
broken with this patch.

This effectively reverts commit f1c72795af573b24a7da5eb52375c9aba8a37972.

Conflicts:

	arch_init.c

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 arch_init.c |   13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 5d32ecf..08fccf6 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -457,15 +457,10 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
             bytes_sent = -1;
             if (is_zero_page(p)) {
                 acct_info.dup_pages++;
-                if (!ram_bulk_stage) {
-                    bytes_sent = save_block_hdr(f, block, offset, cont,
-                                                RAM_SAVE_FLAG_COMPRESS);
-                    qemu_put_byte(f, 0);
-                    bytes_sent++;
-                } else {
-                    acct_info.skipped_pages++;
-                    bytes_sent = 0;
-                }
+                bytes_sent = save_block_hdr(f, block, offset, cont,
+                                            RAM_SAVE_FLAG_COMPRESS);
+                qemu_put_byte(f, 0);
+                bytes_sent++;
             } else if (!ram_bulk_stage && migrate_use_xbzrle()) {
                 current_addr = block->offset + offset;
                 bytes_sent = save_xbzrle_page(f, p, current_addr, block,
-- 
1.7.9.5

  reply	other threads:[~2013-06-10 10:16 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-10 10:14 [Qemu-devel] [PATCHv2 0/2] fix migration of zero pages Peter Lieven
2013-06-10 10:14 ` Peter Lieven [this message]
2013-06-10 15:42   ` [Qemu-devel] [PATCHv2 1/2] Revert "migration: do not sent zero pages in bulk stage" mdroth
2013-06-10 17:08   ` Orit Wasserman
2013-06-13  2:45   ` Wenchao Xia
2013-06-10 10:14 ` [Qemu-devel] [PATCHv2 2/2] migration: do not overwrite zero pages Peter Lieven
2013-06-10 16:10   ` mdroth
2013-06-10 16:17     ` mdroth
2013-06-10 18:50     ` Peter Lieven
2013-06-10 17:13   ` Orit Wasserman
2013-06-13  3:30   ` Wenchao Xia
2013-06-13  6:21     ` Peter Lieven

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