From: Anton Vorontsov <cbouatmailru@gmail.com>
To: Pekka Enberg <penberg@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>,
Leonid Moiseichuk <leonid.moiseichuk@nokia.com>
Subject: Re: vmevent: question?
Date: Mon, 30 Apr 2012 00:54:18 -0700 [thread overview]
Message-ID: <20120430075417.GA8438@lizard> (raw)
In-Reply-To: <CAOJsxLE3A3b5HSrRm0NVCBmzv7AAs-RWEiZC1BL=se309+=WTA@mail.gmail.com>
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?
> > A A 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
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next prev parent reply other threads:[~2012-04-30 7:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-30 7:06 vmevent: question? Minchan Kim
2012-04-30 7:35 ` Pekka Enberg
2012-04-30 7:52 ` Minchan Kim
2012-04-30 8:01 ` Pekka Enberg
2012-04-30 8:36 ` Minchan Kim
2012-05-03 7:24 ` Pekka Enberg
2012-05-03 7:57 ` Minchan Kim
2012-05-03 8:07 ` Pekka Enberg
2012-05-03 8:13 ` Minchan Kim
2012-04-30 7:54 ` Anton Vorontsov [this message]
2012-04-30 8:03 ` Pekka Enberg
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