migration: move calling save_zero_page to the common place
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>
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105
migration/ram.c
105
migration/ram.c
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@ -1038,15 +1038,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
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trace_ram_save_page(block->idstr, (uint64_t)offset, p);
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XBZRLE_cache_lock();
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pages = save_zero_page(rs, block, offset);
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if (pages > 0) {
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/* Must let xbzrle know, otherwise a previous (now 0'd) cached
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* page would be stale
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*/
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xbzrle_cache_zero_page(rs, current_addr);
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ram_release_pages(block->idstr, offset, pages);
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} else if (!rs->ram_bulk_stage &&
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!migration_in_postcopy() && migrate_use_xbzrle()) {
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if (!rs->ram_bulk_stage && !migration_in_postcopy() &&
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migrate_use_xbzrle()) {
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pages = save_xbzrle_page(rs, &p, current_addr, block,
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offset, last_stage);
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if (!last_stage) {
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@ -1194,40 +1187,23 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,
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p = block->host + offset;
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/* When starting the process of a new block, the first page of
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* the block should be sent out before other pages in the same
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* block, and all the pages in last block should have been sent
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* out, keeping this order is important, because the 'cont' flag
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* is used to avoid resending the block name.
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*/
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if (block != rs->last_sent_block) {
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flush_compressed_data(rs);
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pages = save_zero_page(rs, block, offset);
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if (pages > 0) {
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ram_release_pages(block->idstr, offset, pages);
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} else {
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/*
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* Make sure the first page is sent out before other pages.
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*
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* we post it as normal page as compression will take much
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* CPU resource.
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*/
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ram_counters.transferred += save_page_header(rs, rs->f, block,
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offset | RAM_SAVE_FLAG_PAGE);
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qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,
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migrate_release_ram() &
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migration_in_postcopy());
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ram_counters.transferred += TARGET_PAGE_SIZE;
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ram_counters.normal++;
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pages = 1;
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}
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/*
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* Make sure the first page is sent out before other pages.
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*
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* we post it as normal page as compression will take much
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* CPU resource.
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*/
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ram_counters.transferred += save_page_header(rs, rs->f, block,
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offset | RAM_SAVE_FLAG_PAGE);
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qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,
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migrate_release_ram() &
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migration_in_postcopy());
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ram_counters.transferred += TARGET_PAGE_SIZE;
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ram_counters.normal++;
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pages = 1;
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} else {
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pages = save_zero_page(rs, block, offset);
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if (pages == -1) {
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pages = compress_page_with_multi_thread(rs, block, offset);
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} else {
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ram_release_pages(block->idstr, offset, pages);
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}
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pages = compress_page_with_multi_thread(rs, block, offset);
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}
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return pages;
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@ -1469,6 +1445,24 @@ err:
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return -1;
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}
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static bool save_page_use_compression(RAMState *rs)
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{
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if (!migrate_use_compression()) {
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return false;
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}
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/*
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* If xbzrle is on, stop using the data compression after first
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* round of migration even if compression is enabled. In theory,
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* xbzrle can do better than compression.
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*/
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if (rs->ram_bulk_stage || !migrate_use_xbzrle()) {
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return true;
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}
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return false;
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}
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/**
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* ram_save_target_page: save one target page
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*
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@ -1490,12 +1484,31 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
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}
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/*
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* If xbzrle is on, stop using the data compression after first
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* round of migration even if compression is enabled. In theory,
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* xbzrle can do better than compression.
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* When starting the process of a new block, the first page of
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* the block should be sent out before other pages in the same
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* block, and all the pages in last block should have been sent
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* out, keeping this order is important, because the 'cont' flag
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* is used to avoid resending the block name.
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*/
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if (migrate_use_compression() &&
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(rs->ram_bulk_stage || !migrate_use_xbzrle())) {
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if (block != rs->last_sent_block && save_page_use_compression(rs)) {
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flush_compressed_data(rs);
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}
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res = save_zero_page(rs, block, offset);
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if (res > 0) {
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/* Must let xbzrle know, otherwise a previous (now 0'd) cached
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* page would be stale
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*/
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if (!save_page_use_compression(rs)) {
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XBZRLE_cache_lock();
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xbzrle_cache_zero_page(rs, block->offset + offset);
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XBZRLE_cache_unlock();
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}
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ram_release_pages(block->idstr, offset, res);
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return res;
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}
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if (save_page_use_compression(rs)) {
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return ram_save_compressed_page(rs, pss, last_stage);
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}
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