Re: [Qemu-devel] [PULL 07/11] save_block_hdr: we can recalculate the cont parameter here

[Juan Quintela]

"Li, Liang Z" <address@hidden> wrote:
> Hi Juan
>
>     This patch will make my work more difficult, as we discussed
> before, after modification,
> I have to use a lock before I can reuse the function save_block_hdr in
> my compression threads,
> this will lead to low efficiency. Could help to revert this patch?
>
> Liang

Sorry, my intention was to just revert the bits that you neded, what
does this patch works for you?

I just moved back the uses of last_sent_block() where there were before.

Thanks, Juan.

>From 76bdb0c98e345dcc4777d4b034efd4ccd71489ba Mon Sep 17 00:00:00 2001
From: Juan Quintela <address@hidden>
Date: Tue, 17 Mar 2015 12:56:13 +0100
Subject: [PATCH] migration:  remove last_sent_block from save_page_header

Compression code (still not on tree) want to call this funtion from
outside the migration thread, so we can't write to last_sent_block.

Instead of reverting full patch:

[PULL 07/11] save_block_hdr: we can recalculate

Just revert the parts that touch last_sent_block.

Signed-off-by: Juan Quintela <address@hidden>
---
 arch_init.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index c3f7d3f..c779957 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -332,19 +332,14 @@ static size_t save_page_header(QEMUFile *f, RAMBlock 
*block, ram_addr_t offset)
 {
     size_t size;

-    if (block == last_sent_block) {
-        offset |= RAM_SAVE_FLAG_CONTINUE;
-    }
-
     qemu_put_be64(f, offset);
     size = 8;

-    if (block != last_sent_block) {
+    if (!(offset & RAM_SAVE_FLAG_CONTINUE)) {
         qemu_put_byte(f, strlen(block->idstr));
         qemu_put_buffer(f, (uint8_t *)block->idstr,
                         strlen(block->idstr));
         size += 1 + strlen(block->idstr);
-        last_sent_block = block;
     }
     return size;
 }
@@ -644,6 +639,10 @@ static int ram_save_page(QEMUFile *f, RAMBlock* block, 
ram_addr_t offset,
     XBZRLE_cache_lock();

     current_addr = block->offset + offset;
+
+    if (block == last_sent_block) {
+        offset |= RAM_SAVE_FLAG_CONTINUE;
+    }
     if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
         if (ret != RAM_SAVE_CONTROL_DELAYED) {
             if (bytes_xmit > 0) {
@@ -739,6 +738,7 @@ static int ram_find_and_save_block(QEMUFile *f, bool 
last_stage,

             /* if page is unmodified, continue to the next */
             if (pages > 0) {
+                last_sent_block = block;
                 break;
             }
         }
-- 
2.1.0