Re: [PATCH] struct page shrinkage

[Andrew Morton <akpm@zip.com.au>]

Bulent Abali wrote:
> 
> extern struct page_state {
>              unsigned long nr_dirty;
>              unsigned long nr_locked;
> } ____cacheline_aligned page_states[NR_CPUS];
> 
> This is perfect.   Looks like, if a run summation over all the CPUs I will
> get the total locked and dirty pages, provided mm.h macros are respected.

That's correct.  And the mm.h macros *are* respected.  That patch
ensures that they are.

It goes as far as to rename PG_locked and PG_dirty to PG_locked_dontuse
and PG_dirty_dontuse.

I'll be adding page_cache_size to the above struct, at least.

The "run summation" function is already there, btw: get_page_state().

> What is the outlook for inclusion of this patch in the main kernel?  Do you
> plan to submit or have been included yet?

Well it's all a part of a work to aggressively improve the efficiency
of regular file I/O.  I don't know if the big grand plan will be successful
yet.  At this time, it's thumbs up - way up.

Nor do I know if this is a direction in which Linus wishes to take
his kernel.

But this change, the readahead changes, the pdflush pool and a few other
pieces I have planned are probably appropriate for the base kernel
irrespective of the end outcome.

We'll see...

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