Re: [PATCH 2/2] Futex non-page-pinning fix

[Andrew Morton]

Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:
>
> > I think a better place to rehash the futex would be at the point where the
>  > page is added to and removed from swapcache.
> 
>  This is simplest: the current code actually moves the futex queue out
>  of the hash.  If we make the rule: "call futex_rehash" every time
>  page->mapping (or page->index) changes, we avoid races and make the
>  code simpler.
> 
>  But this means it could be called quite often.

Moving pages to and from swapcache really is not a fastpath at all,
so I wouldn't be worrying about that.

And even if the code is sucky, it will only be sucky when there is a lot of
swapcache activity AND a lot of futexes are in use.



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/