Re: mm: remove vmalloc info from /proc/meminfo

From: Dave Jones
Date: Mon Nov 02 2015 - 15:10:42 EST


On Mon, Nov 02, 2015 at 11:29:15AM -0800, Linus Torvalds wrote:
> On Mon, Nov 2, 2015 at 10:36 AM, Dave Jones <dsj@xxxxxx> wrote:
> > Reading /proc/meminfo is really slow, as it requires recomputing the
> > vmalloc data every time, which is a lot of work, when most (all?)
> > consumers of meminfo don't even care about those statistics.
>
> Ahh. My version of this patch (which I actually committed yesterday,
> since I remembered - will wonders never cease?) leaves the fields
> around in the /proc/meminfo file, but just makes the values be zero.
> It also removes the actual function to compute the data that nobody
> uses any more.
>
> I agree that we can eventually look at even removing the fields
> entirely, but that's much more likely to break things. I can imagine
> system tools that just root around for values, and break and complain
> when they don't exist, even if all they do is report them (rather than
> actually *use* them for anythign).
>
> I guess I should just push out my tree. I didn't want to keep people
> from testing plain 4.3, so I didn't push out yesterday.
>
> Can you test what is now (where "now" means "it might take a minute or
> two to mirror out") in my git repo?

That looks like it'll do the job just as well yeah, and I suppose is
a touch more conservative than my "burn it all down" approach.

Dave

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