On Fri, 2014-06-13 at 12:28 -0400, Johannes Weiner wrote:
> On Fri, Jun 13, 2014 at 01:21:15PM +0800, Chen Yucong wrote:
> > On Thu, 2014-06-12 at 21:40 -0700, Andrew Morton wrote:
> > > On Fri, 13 Jun 2014 12:36:31 +0800 Chen Yucong <sla...@gmail.com> wrote:
> > >
> > > > @@ -1148,7 +1146,8 @@ unsigned long
> > > > reclaim_clean_pages_from_list(struct zone *zone,
> > > > .priority = DEF_PRIORITY,
> > > > .may_unmap = 1,
> > > > };
> > > > - unsigned long ret, dummy1, dummy2, dummy3, dummy4, dummy5;
> > > > + unsigned long ret;
> > > > + struct shrink_result dummy = { };
> > >
> > > You didn't like the idea of making this static?
> > Sorry! It's my negligence.
> > If we make dummy static, it can help us save more stack.
> >
> > without change:
> > 0xffffffff810aede8 reclaim_clean_pages_from_list []: 184
> > 0xffffffff810aeef8 reclaim_clean_pages_from_list []: 184
> >
> > with change: struct shrink_result dummy = {};
> > 0xffffffff810aed6c reclaim_clean_pages_from_list []: 152
> > 0xffffffff810aee68 reclaim_clean_pages_from_list []: 152
> >
> > with change: static struct shrink_result dummy ={};
> > 0xffffffff810aed69 reclaim_clean_pages_from_list []: 120
> > 0xffffffff810aee4d reclaim_clean_pages_from_list []: 120
>
> FWIW, I copied bloat-o-meter and hacked up a quick comparison tool
> that you can feed two outputs of checkstack.pl for a whole vmlinux and
> it shows you the delta.
>
> The output for your patch (with the static dummy) looks like this:
>
> +0/-240 -240
> shrink_inactive_list 136 112 -24
> shrink_page_list 208 160 -48
> reclaim_clean_pages_from_list 168 - -168
>
> (The stack footprint for reclaim_clean_pages_from_list is actually 96
> after your patch, but checkstack.pl skips frames under 100)
>
Thanks very much for your comparison tool. Its output is more concise.
thx!
cyc
gcc version 4.7.3 (Gentoo 4.7.3-r1 p1.4, pie-0.5.5)
kernel version 3.15(stable)
Intel(R) Core(TM)2 Duo CPU T5670 @ 1.80GHz
The output for this patch (with the static dummy) is:
+0/-144 -144
shrink_inactive_list 152 120 -32
shrink_page_list 232 184 -48
reclaim_clean_pages_from_list 184 120 -64
-------
gcc version 4.7.2 (Debian 4.7.2-5)
kernel version 3.15(stable)
Intel(R) Core(TM) i5-2320 CPU @ 3.00GHz
The output for this patch (with the static dummy) is:
shrink_inactive_list 136 120 -16
shrink_page_list 216 168 -48
reclaim_clean_pages_from_list 184 120 -64
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