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migration: move calling save_zero_page to the common place

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save_zero_page() is always our first approach to try, move it to
the common place before calling ram_save_compressed_page
and ram_save_page

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Message-Id: <20180330075128.26919-9-xiaoguangrong@tencent.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Xiao Guangrong 2018-03-30 15:51:26 +08:00 committed by Dr. David Alan Gilbert
parent a8ec91f941
commit d7400a3409
1 changed files with 59 additions and 46 deletions
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105
migration/ram.c
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@ -1038,15 +1038,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
trace_ram_save_page(block->idstr, (uint64_t)offset, p);
XBZRLE_cache_lock();
pages = save_zero_page(rs, block, offset);
if (pages > 0) {
/* Must let xbzrle know, otherwise a previous (now 0'd) cached
* page would be stale
*/
xbzrle_cache_zero_page(rs, current_addr);
ram_release_pages(block->idstr, offset, pages);
} else if (!rs->ram_bulk_stage &&
!migration_in_postcopy() && migrate_use_xbzrle()) {
if (!rs->ram_bulk_stage && !migration_in_postcopy() &&
migrate_use_xbzrle()) {
pages = save_xbzrle_page(rs, &p, current_addr, block,
offset, last_stage);
if (!last_stage) {
@ -1194,40 +1187,23 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,
p = block->host + offset;
/* When starting the process of a new block, the first page of
* the block should be sent out before other pages in the same
* block, and all the pages in last block should have been sent
* out, keeping this order is important, because the 'cont' flag
* is used to avoid resending the block name.
*/
if (block != rs->last_sent_block) {
flush_compressed_data(rs);
pages = save_zero_page(rs, block, offset);
if (pages > 0) {
ram_release_pages(block->idstr, offset, pages);
} else {
/*
* Make sure the first page is sent out before other pages.
*
* we post it as normal page as compression will take much
* CPU resource.
*/
ram_counters.transferred += save_page_header(rs, rs->f, block,
offset | RAM_SAVE_FLAG_PAGE);
qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,
migrate_release_ram() &
migration_in_postcopy());
ram_counters.transferred += TARGET_PAGE_SIZE;
ram_counters.normal++;
pages = 1;
}
/*
* Make sure the first page is sent out before other pages.
*
* we post it as normal page as compression will take much
* CPU resource.
*/
ram_counters.transferred += save_page_header(rs, rs->f, block,
offset | RAM_SAVE_FLAG_PAGE);
qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,
migrate_release_ram() &
migration_in_postcopy());
ram_counters.transferred += TARGET_PAGE_SIZE;
ram_counters.normal++;
pages = 1;
} else {
pages = save_zero_page(rs, block, offset);
if (pages == -1) {
pages = compress_page_with_multi_thread(rs, block, offset);
} else {
ram_release_pages(block->idstr, offset, pages);
}
pages = compress_page_with_multi_thread(rs, block, offset);
}
return pages;
@ -1469,6 +1445,24 @@ err:
return -1;
}
static bool save_page_use_compression(RAMState *rs)
{
if (!migrate_use_compression()) {
return false;
}
/*
* If xbzrle is on, stop using the data compression after first
* round of migration even if compression is enabled. In theory,
* xbzrle can do better than compression.
*/
if (rs->ram_bulk_stage || !migrate_use_xbzrle()) {
return true;
}
return false;
}
/**
* ram_save_target_page: save one target page
*
@ -1490,12 +1484,31 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
}
/*
* If xbzrle is on, stop using the data compression after first
* round of migration even if compression is enabled. In theory,
* xbzrle can do better than compression.
* When starting the process of a new block, the first page of
* the block should be sent out before other pages in the same
* block, and all the pages in last block should have been sent
* out, keeping this order is important, because the 'cont' flag
* is used to avoid resending the block name.
*/
if (migrate_use_compression() &&
(rs->ram_bulk_stage || !migrate_use_xbzrle())) {
if (block != rs->last_sent_block && save_page_use_compression(rs)) {
flush_compressed_data(rs);
}
res = save_zero_page(rs, block, offset);
if (res > 0) {
/* Must let xbzrle know, otherwise a previous (now 0'd) cached
* page would be stale
*/
if (!save_page_use_compression(rs)) {
XBZRLE_cache_lock();
xbzrle_cache_zero_page(rs, block->offset + offset);
XBZRLE_cache_unlock();
}
ram_release_pages(block->idstr, offset, res);
return res;
}
if (save_page_use_compression(rs)) {
return ram_save_compressed_page(rs, pss, last_stage);
}