Commit d7400a34 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Dr. David Alan Gilbert
Browse files

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: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@tencent.com>
Message-Id: <20180330075128.26919-9-xiaoguangrong@tencent.com>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
parent a8ec91f9

migration/ram.c

+59 −46
Original line number Diff line number Diff line
@@ -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) {
@@ -1194,18 +1187,7 @@ 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.

         *
@@ -1220,14 +1202,8 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss, 
        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);

        }

    }



    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 (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 (migrate_use_compression() &&

        (rs->ram_bulk_stage || !migrate_use_xbzrle())) {

        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);

    }