Hi Jakub, > That would mean an additional syscall. Furthermore, if you allocate a big > chunk of memory, dirty it, then free (with madvise (MADV_FREE)) it and soon > allocate the same size of memory again, it is better to start that with > non-dirty memory, it might be that this time you e.g. don't modify a big > part of the chunk. If all that memory was kept dirty all the time and > just marked/unmarked for lazy reuse with MADV_FREE/MADV_UNDO_FREE, all that > memory would need to be saved to disk when paging out as it was marked > dirty, while with current Rik's MADV_FREE that will happen only for pages > that were actually dirtied after the last malloc.
Yep this all makes sense. I was looking at it from the other angle where on some workloads we have to force malloc to use brk for best performance. Im sure the MADV_FREE changes will close that gap but it would be interesting to see if there is still a gap on the problem workloads. Maybe Im worrying about nothing. Anton - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
