Heavy disk I/O while Waylaying

[xulai1001]

The "relocate.c" program causes extremely high disk I/O loads while working, because it needs to read the randomized "evict" file to get rid of all page caches.

In order to finally relocate a target binary to the desired physical address, it needs to be executed 10,000+ times, which costs several days according to the Flip-in-the-wall article. During the process, although the memory consumption does remain unchanged, the heavy disk I/O load slows the whole system down and can be easily detected.

So, Is there any more efficient way to relocate a binary to a certain phys-addr? (Outside enclaves, root privileges are also OK). I want to optimize the process so that I won't wait for days for this step.

I have tried (below):

• Waylaying: ~10-30s per run (depending on hdd speed, mine is slow), memory coverage is good.
• Chasing (with copy-on-write fork()): very fast, but my program always returns repeated addresses. I can only get ~8MB different pages (~2000 pages). Where did I do wrong?
• posix_fadvise(): can actually relocate, but only gets ~32MB different pages, coverage is poor.
• posix_fadvise() + some Waylaying: only gets ~100MB different pages.

I have not tried /proc/sys/vm/drop_caches but I feel it does not help much.