Re: [PATCH v2] mm/vmscan.c: wrap five parameters into shrink_result for reducing the stack consumption

From: Chen Yucong
Date: Fri Jun 13 2014 - 01:23:58 EST


On Thu, 2014-06-12 at 21:40 -0700, Andrew Morton wrote:
> On Fri, 13 Jun 2014 12:36:31 +0800 Chen Yucong <slaoub@xxxxxxxxx> 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

thx!
cyc

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