Re: increased vmap_area_lock contentions on "n_tty: Move buffersinto n_tty_data"

[Peter Hurley]

On 09/25/2013 05:04 AM, Lin Ming wrote:
> On Wed, Sep 18, 2013 at 8:22 AM, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:
> [snip]
> > Looking over vmalloc.c, the critical section footprint of the vmap_area_lock
> > could definitely be reduced (even nearly eliminated), but that's a project
> > for
> > another day :)
>
> Hi Peter,
>
> I also looked over vmallo.c, but didn't find obvious way to reduce the
> critical section footprint.
> Could you share some hints how to do this?

vmap_area_list is an RCU list.
get_vmalloc_info() doesn't need to take the vmap_area_lock at all.
Look at __purge_vmap_area_lazy() for a howto.

Regards,
Peter Hurley

--
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/