On 10/16/13 8:57 PM, Prakash Surya wrote: > Well, we're just increasing the size of the hash. So, given enough RAM, > the problem of having enough buffers in the cache to cause large chains > still exists. Right? Although, "enough RAM" might not be practically > achievable.
It would only be a problem if our relative resource usage changed depending on the amount of the resource being present, i.e. if we used 0.1% of physmem at 1GB but 1% at 1TB and 10% at 1PB - that is a problem that's getting out of hand and doesn't scale. But in this case, the relative proportions *don't* change. It's still going to be 0.1%, regardless of the actual amount of physical memory present. > I'm no VM expert either, but speaking from Linux's perspective, I don't > think virtual address space fragmentation is much of an issue. AFAIK, > whether you're doing a 1M vmalloc or 1G vmalloc, VM fragmentation > doesn't play much of an issue. The kernel will allocate non-contiguous > pages and then present them as a contiguous region, so you just need > enough free pages on the system to satisfy the request. > > I should try and prod behlendorf about this, since he has much more > experience on the subject than I do. > Please do, I'd be very happy to simplify the code. Cheers, -- Saso _______________________________________________ developer mailing list [email protected] http://lists.open-zfs.org/mailman/listinfo/developer
