Re: [PATCH] Add __GFP_MOVABLE for callers to flag allocations that may be migrated

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Peter Zijlstra wrote:
On Mon, 2006-12-04 at 11:30 -0800, Andrew Morton wrote:

I'd also like to pin down the situation with lumpy-reclaim versus
anti-fragmentation.  No offence, but I would of course prefer to avoid
merging the anti-frag patches simply based on their stupendous size.  It
seems to me that lumpy-reclaim is suitable for the e1000 problem, but
perhaps not for the hugetlbpage problem.  Whereas anti-fragmentation adds
vastly more code, but can address both problems?  Or something.

From my understanding they complement each other nicely. Without some
form of anti fragmentation there is no guarantee lumpy reclaim will ever
free really high order pages. Although it might succeed nicely for the
network sized allocations we now have problems with.

- Andy, do you have any number on non largepage order allocations?

Currently no, we have focused on the worst case huge pages and assumed lower orders would be easier and more successful. Though it is (now) on my todo list to see if we can do the same tests at some lower order; with the aim of trying that on base+lumpy.

But anti fragmentation as per Mel's patches is not good enough to
provide largepage allocations since we would need to shoot down most of
the LRU to obtain such a large contiguous area. Lumpy reclaim however
can quickly achieve these sizes.

-apw
-
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/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux