Re: [patch 00/14] Page cache cleanup in anticipation of Large Blocksize support

Andrew Morton
2007-06-14T21:33:10Z

> On Thu, 14 Jun 2007 14:20:04 -0700 (PDT) Christoph Lameter <clameter@sgi.com> wrote:
> > I think the best way to proceed would be to investigate that _general_
> > optimisation and then, based upon the results of that work, decide whether
> > further _specialised_ changes such as variable PAGE_CACHE_SIZE are needed,
> > and if so, what they should be.
>
> As has been pointed out performance is only one beneficial issue of
> having a higher page cache. It is doubtful in principle that the proposed
> alternative can work given that locking overhead and management overhead
> by the VM are not minimized but made more complex by your envisioned
> solution.

Why do we have to replay all of this?

You: conceptully-new add-on which benefits 0.25% of the user base, provided
they select the right config options and filesystem.

Me: simpler enhancement which benefits 100% of the user base (ie: includes
4k blocksize, 4k pagesize) and which also fixes your performance problem
with that HBA.

We want the 100% case.