Re: [PATCH] proc: faster /proc/*/status

From	Andrew Morton <akpm@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] proc: faster /proc/*/status
Date	2016-08-10 01:30 +0200
Message-ID	<s4oD7-5EB-1@gated-at.bofh.it> (permalink)
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On Sun, 07 Aug 2016 14:22:31 -0700 Joe Perches <joe@perches.com> wrote:

> On Sun, 2016-08-07 at 10:44 -0700, Andi Kleen wrote:
> > > > > It is so bloated that gcc needs to be asked to not screw up with stack
> > > > > size.
> > > > What happens when you drop all the noinlines for this? I assume
> > > > this would alread make it faster. And now that we have bigger
> > > > stacks we can likely tolerate it.
> > > %pV recurses through these code paths.
> > > I believe the maximum current recursion depth is 3.
> > I assume 2 max would sufficient for all users in kernel.
> > 
> > And perhaps it would be better to get rid of "features" like this,
> > and instead focus on more common cases.
> 
> It'd be a dubious trade-off in my opinion.
> 
> Overall code size has been reduced by hundreds of KB
> by using %pV.

I kinda like Alexey's patch just for aesthetic reasons.  Those huge
straggly printk-style statements are a real pain to maintain, trying to
keep the control string and the args in sync.  Especially when there are
ifdefs everywhere - take a look at meminfo_proc_show() and weep.  Geeze
the number of times I've had to maintain (and screw up) conflicts in
that thing...

Thread

[PATCH] proc: faster /proc/*/status Alexey Dobriyan <adobriyan@gmail.com> - 2016-08-06 23:50 +0200
  Re: [PATCH] proc: faster /proc/*/status Joe Perches <joe@perches.com> - 2016-08-07 00:50 +0200
    [PATCH] seq/proc: Modify seq_put_decimal_[u]ll to take a const char *, not char Joe Perches <joe@perches.com> - 2016-08-09 05:10 +0200
  Re: [PATCH] proc: faster /proc/*/status Andi Kleen <andi@firstfloor.org> - 2016-08-07 05:20 +0200
    Re: [PATCH] proc: faster /proc/*/status Alexey Dobriyan <adobriyan@gmail.com> - 2016-08-07 11:00 +0200
      Re: [PATCH] proc: faster /proc/*/status Andi Kleen <andi@firstfloor.org> - 2016-08-07 19:00 +0200
        Re: [PATCH] proc: faster /proc/*/status Joe Perches <joe@perches.com> - 2016-08-07 19:40 +0200
          Re: [PATCH] proc: faster /proc/*/status Andi Kleen <andi@firstfloor.org> - 2016-08-07 19:50 +0200
            Re: [PATCH] proc: faster /proc/*/status Joe Perches <joe@perches.com> - 2016-08-07 23:30 +0200
              Re: [PATCH] proc: faster /proc/*/status Andrew Morton <akpm@linux-foundation.org> - 2016-08-10 01:30 +0200
                [RFC PATCH] meminfo: Break apart a very long seq_printf with #ifdefs Joe Perches <joe@perches.com> - 2016-08-10 20:30 +0200

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