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 <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
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)
---
#!/usr/bin/python
#
# Based on bloat-o-meter
import sys
import re
if len(sys.argv) != 3:
print("usage: %s file1 file2" % sys.argv[0])
sys.exit(1)
def getsizes(filename):
sym = {}
for line in open(filename):
x = re.split('(0x.*) (.*) (.*):[ \t]*(.*)', line)
try:
foo, addr, name, src, size, bar = x
except:
print(x)
raise Exception
try:
sym[name] = int(size)
except:
continue
return sym
old = getsizes(sys.argv[1])
new = getsizes(sys.argv[2])
inc = 0
dec = 0
delta = []
common = {}
for a in old:
if a in new:
common[a] = 1
for name in old:
if name not in common:
dec += old[name]
delta.append((-old[name], name))
for name in new:
if name not in common:
inc += new[name]
delta.append((new[name], name))
for name in common:
d = new.get(name, 0) - old.get(name, 0)
if d > 0: inc += d
if d < 0: dec -= d
delta.append((d, name))
delta.sort()
delta.reverse()
print("+%d/-%d %+d" % (inc, dec, inc - dec))
for d, name in delta:
if d:
print("%-40s %7s %7s %+7d" % (name, old.get(name, "-"), new.get(name, "-"), d))
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