[Crash-utility] what is recommended dump level

Hi, all. what is recommended dump level when using makedumpfile (kdump)? I'm looking for explanation like this. ------------ from diskdump document -------------------- Note that the partial dump feature has some risks. There are memory management lists which are scanned for a page's memory attribute, so if the list has been corrupted, the scanning process may fail. For example, when specifying a dump_level from 4-7 or from 12-15, the kernel's free page linked lists are scanned; if the list is corrupt, diskdump may hang. Furthermore, it is possible that a page type that has been skipped may be necessary to fully investigate the cause of some issues. Therefore, a memory collection level should be selected to suit each situation. The recommended level is 19, because it is easiest to determine whether a page is zero-filled or if it is a page cache page, and because no page lists need to be traversed. ------------------------------------------------------- Does anyone know document describing these things when using makedumpfile ? Thanks, toku.