Re: [patch 13/14] fs: icache split IO and LRU lists

From: Nick Piggin
Date: Thu Oct 21 2010 - 21:05:41 EST


On Fri, Oct 22, 2010 at 11:00:28AM +1100, Nick Piggin wrote:
> On Thu, Oct 21, 2010 at 10:28:42AM -0500, Christoph Lameter wrote:
> > On Fri, 22 Oct 2010, npiggin@xxxxxxxxx wrote:
> >
> > > Split inode reclaim and writeback lists in preparation to scale them up
> > > (per-bdi locking for i_io and per-zone locking for i_lru)
> >
> > Why per zone and not per node? Is there any chance of having lru lists for
> > ZONE_NORMAL and ZONE_DMA?
>
> I guess I see that as coupling a bit too much with the MM. We know that
> zones are the unit of allocation and reclaim, but I don't think we need
> to care about which zones we need to care about, or the node:zone
> relationship.

But let's not worry about that in the context of this patch set.
This is just a minimal lock breaking, and the scalability steps can
go in any direction after this. I think zone based reclaim seems to
be the way to go, but we could discuss the point in a patch that
implements it, on top of this series.

Thanks,
Nick

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