lkml.org 
[lkml]   [2012]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: vmevent: question?
Hello Pekka,

On Mon, Apr 30, 2012 at 10:35:02AM +0300, Pekka Enberg wrote:
> > vmevent_smaple gathers all registered values to report to user if vmevent match.
> > But the time gap between vmevent match check and vmevent_sample_attr could make error
> > so user could confuse.
> >
> > Q 1. Why do we report _all_ registered vmstat value?
> >     In my opinion, it's okay just to report _a_ value vmevent_match happens.
>
> It makes the userspace side simpler for "lowmem notification" use
> case. I'm open to changing the ABI if it doesn't make the userspace
> side too complex.

Yep. Actually, I'd like to add something like 'file_pages - shmem'
attribute, and reporting both (i.e. this new attr and free_pages)
values at the same time (even if just one crossed the threshold).

Reporting all the values would help userspace logic (so it won't
need to read /proc again).

> > Q 4. Do you have any plan for this patchset to merge into mainline?
>
> Yes, I'm interested in pushing it forward if we can show that the ABI
> makes sense, is stable and generic enough, and fixes real world
> problems.

It seems to be a pretty nice driver. Speaking of ABI, the only thing
I personally dislike is VMEVENT_CONFIG_MAX_ATTRS (i.e. fixed-size
array in vmevent_config)... but I guess it's pretty easy to make
it variable-sized array... was there any particular reason to make
the _MAX thing?

Thanks!

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

\
 
 \ /
  Last update: 2012-04-30 10:01    [W:2.648 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site