In the last episode (Apr 07), Peter Wemm said: > On Friday 07 April 2006 04:01 pm, Paul Marciano wrote: > > Do you compress the data stream at all (e.g. gzip)? > > No, but it could be done in theory.. if you were willing to set aside > some memory for the compression algorithm to use. Or just do some > sort of simple compression (run length encoding?) The problem is that > the dump code cannot allocate memory after the machine has crashed. > It has to be able to run as isolated from the rest of the kernel as > possible in order to give a true snapshot of the undisturbed state.
This is pretty easy since zlib lets you pass in your own malloc/free functions. It's sufficient to pre-malloc (or simply statically declare) a 128k block of memory, then dole it out with a simple function that returns high_water+=asked_for_size until you get a request that would push highwater over 128k. A patch that does this for 5.* on x86 only is at http://www.allantgroup.com/FreeBSD/crashdump_compress.diff . -- Dan Nelson [EMAIL PROTECTED] _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"