Hi, > Oh. I was assuming that we'd want to unmap these pages from pagetables and > mark then super-easily-reclaimable. So a later touch would incur a minor > fault. > > But you think that we should leave them mapped into pagetables so no such > fault occurs.
That would be very nice. The issues are not limited to threaded apps, we have seen performance problems with single threaded HPC applications that do a lot of large malloc/frees. It turns out the continual set up and tear down of pagetables when malloc uses mmap/free is a problem. At the moment the workaround is: export MALLOC_MMAP_MAX_=0 MALLOC_TRIM_THRESHOLD_=-1 which forces glibc malloc to use brk instead of mmap/free. Of course brk is good for keeping pagetables around but bad for keeping memory usage down. 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/
