Re: [rfc] lockless pagecache

[Andrew Morton]

Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:
>
> Also, the memory usage regression cases that fault ahead brings makes it
>  a bit contentious.

faultahead consumes no more memory: if the page is present then point a pte
at it.  It'll make reclaim work a bit harder in some situations.

>  I like that the lockless patch completely removes the problem at its
>  source and even makes the serial path lighter. The other things is, the
>  speculative get_page may be useful for more code than just pagecache
>  lookups. But it is fairly tricky I'll give you that.

Yes, it's scary-looking stuff.

>  Anyway it is obviously not something that can go in tomorrow. At the
>  very least the PageReserved patches need to go in first, and even they
>  will need a lot of testing out of tree.
> 
>  Perhaps it can be discussed at KS and we can think about what to do with
>  it after that - that kind of time frame. No rush.
> 
>  Oh yeah, and obviously it would be nice if it provided real improvements
>  on real workloads too ;)

umm, yes.
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