Messages in this thread | | | Date | Mon, 30 Apr 2012 00:54:18 -0700 | From | Anton Vorontsov <> | Subject | Re: vmevent: question? |
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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/
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