KVM Archive on lore.kernel.org
 help / color / Atom feed
From: Juan Quintela <quintela@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Juan Quintela <quintela@redhat.com>,
	Laurent Vivier <lvivier@redhat.com>,
	kvm@vger.kernel.org, Thomas Huth <thuth@redhat.com>,
	Richard Henderson <rth@twiddle.net>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Wei Yang <richardw.yang@linux.intel.com>
Subject: [PULL 05/19] migration/xbzrle: update cache and current_data in one place
Date: Thu, 11 Jul 2019 12:43:58 +0200
Message-ID: <20190711104412.31233-6-quintela@redhat.com> (raw)
In-Reply-To: <20190711104412.31233-1-quintela@redhat.com>

From: Wei Yang <richardw.yang@linux.intel.com>

When we are not in the last_stage, we need to update the cache if page
is not the same.

Currently this procedure is scattered in two places and mixed with
encoding status check.

This patch extract this general step out to make the code a little bit
easy to read.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Message-Id: <20190610004159.20966-1-richardw.yang@linux.intel.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 74c9306c78..d3d72b6f4f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1585,25 +1585,30 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
     encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,
                                        TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
                                        TARGET_PAGE_SIZE);
+
+    /*
+     * Update the cache contents, so that it corresponds to the data
+     * sent, in all cases except where we skip the page.
+     */
+    if (!last_stage && encoded_len != 0) {
+        memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
+        /*
+         * In the case where we couldn't compress, ensure that the caller
+         * sends the data from the cache, since the guest might have
+         * changed the RAM since we copied it.
+         */
+        *current_data = prev_cached_page;
+    }
+
     if (encoded_len == 0) {
         trace_save_xbzrle_page_skipping();
         return 0;
     } else if (encoded_len == -1) {
         trace_save_xbzrle_page_overflow();
         xbzrle_counters.overflow++;
-        /* update data in the cache */
-        if (!last_stage) {
-            memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE);
-            *current_data = prev_cached_page;
-        }
         return -1;
     }
 
-    /* we need to update the data in the cache, in order to get the same data */
-    if (!last_stage) {
-        memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
-    }
-
     /* Send XBZRLE based compressed page */
     bytes_xbzrle = save_page_header(rs, rs->f, block,
                                     offset | RAM_SAVE_FLAG_XBZRLE);
-- 
2.21.0


  parent reply index

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-11 10:43 [PULL 00/19] Migration patches Juan Quintela
2019-07-11 10:43 ` [PULL 01/19] migration: fix multifd_recv event typo Juan Quintela
2019-07-11 10:43 ` [PULL 02/19] migration-test: rename parameter to parameter_int Juan Quintela
2019-07-11 10:43 ` [PULL 03/19] migration-test: Add migration multifd test Juan Quintela
2019-07-11 10:43 ` [PULL 04/19] migration/multifd: call multifd_send_sync_main when sending RAM_SAVE_FLAG_EOS Juan Quintela
2019-07-11 10:43 ` Juan Quintela [this message]
2019-07-11 10:43 ` [PULL 06/19] cutils: remove one unnecessary pointer operation Juan Quintela
2019-07-11 10:44 ` [PULL 07/19] migration/multifd: sync packet_num after all thread are done Juan Quintela
2019-07-11 10:44 ` [PULL 08/19] migratioin/ram.c: reset complete_round when we gets a queued page Juan Quintela
2019-07-11 10:44 ` [PULL 09/19] migration: No need to take rcu during sync_dirty_bitmap Juan Quintela
2019-07-11 10:44 ` [PULL 10/19] memory: Don't set migration bitmap when without migration Juan Quintela
2019-07-11 10:44 ` [PULL 11/19] bitmap: Add bitmap_copy_with_{src|dst}_offset() Juan Quintela
2019-07-11 10:44 ` [PULL 12/19] memory: Pass mr into snapshot_and_clear_dirty Juan Quintela
2019-07-11 10:44 ` [PULL 13/19] memory: Introduce memory listener hook log_clear() Juan Quintela
2019-07-11 10:44 ` [PULL 14/19] kvm: Update comments for sync_dirty_bitmap Juan Quintela
2019-07-11 10:44 ` [PULL 15/19] kvm: Persistent per kvmslot dirty bitmap Juan Quintela
2019-07-11 10:44 ` [PULL 16/19] kvm: Introduce slots lock for memory listener Juan Quintela
2019-07-11 10:44 ` [PULL 17/19] kvm: Support KVM_CLEAR_DIRTY_LOG Juan Quintela
2019-07-11 10:44 ` [PULL 19/19] migration: allow private destination ram with x-ignore-shared Juan Quintela
2019-07-11 11:19 ` [PULL 00/19] Migration patches Paolo Bonzini
2019-07-11 11:32   ` Juan Quintela
2019-07-11 11:34   ` Dr. David Alan Gilbert
2019-07-11 11:40     ` [Qemu-devel] " Peter Maydell
2019-07-11 12:39 ` Peter Maydell
2019-07-12 14:06   ` Juan Quintela
2019-07-11 12:55 ` Christian Borntraeger
2019-07-11 13:01   ` [Qemu-devel] " Peter Maydell
2019-07-11 13:00 ` no-reply
2019-07-12 14:33 ` no-reply
2019-07-12 14:31 Juan Quintela
2019-07-12 14:31 ` [PULL 05/19] migration/xbzrle: update cache and current_data in one place Juan Quintela

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190711104412.31233-6-quintela@redhat.com \
    --to=quintela@redhat.com \
    --cc=dgilbert@redhat.com \
    --cc=kvm@vger.kernel.org \
    --cc=lvivier@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-devel@nongnu.org \
    --cc=richardw.yang@linux.intel.com \
    --cc=rth@twiddle.net \
    --cc=thuth@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

KVM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvm/0 kvm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvm kvm/ https://lore.kernel.org/kvm \
		kvm@vger.kernel.org
	public-inbox-index kvm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.kvm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git