link each active block to it's page url I want to link availaible block bids with active url. Then i want to clear page cache by block. How to do that best way? I wanted to use

block_list($region)


But it's overhead.
Knowing where any block is displayed can be tricky; you would need to keep a nontrivial database table in order to do that (Boost 6.x does this with nodes that are in panels and views). A better option would be to output the block via AJAX or ESI.

http://drupal.org/project/esi/ (has ajax output option)
http://drupal.org/project/ajaxblocks/
http://drupal.org/project/ajaxify_regions/