Re: [RESEND][PATCH V1] mm/vsmcan: check shrink_active_list() sc->isolate_pages() return value.

[Vincent Li <root@brc.ubc.ca>]

On Wed, 9 Sep 2009, Minchan Kim wrote:

>
> You're right. the experiment said so.
> But hackbench performs fork-bomb test
> so that it makes corner case, I think.
> Such a case shows the your patch is good.
> But that case is rare.
>
> The thing remained is to test your patch
> in normal case. so you need to test hackbench with
> smaller parameters to make for the number of task
> to fit your memory size but does happen reclaim.
>

Hi Kim,

I finally got some time to rerun the perf test and press Alt + SysRq 
+ M the same time  on a freshly start computer.

I run the perf with repeat only 1 instead of 5, so run hackbench 
with number 100 does not cause my system stall, the system  is still quite 
responsive during the test, I assume that is normal situation, not fork 
bomb case?

In general, it seems nr_taken_zero does happen in normal page reclaim 
situation, but it is also true that nr_taken_zero does not happen from 
time to time.


###1 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 80
Running with 80*40 (== 3200) tasks.
Time: 4.912

  Performance counter stats for 'hackbench 80':

               0  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
               0  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

     5.286915156  seconds time elapsed


[   45.290044] SysRq : Show Memory
[   45.291132] active_anon:3283 inactive_anon:0 isolated_anon:0
[   45.291133]  active_file:2538 inactive_file:7964 isolated_file:0

###2 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 90
Running with 90*40 (== 3600) tasks.
Time: 12.548

  Performance counter stats for 'hackbench 90':

              76  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
             361  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

    12.980680642  seconds time elapsed

[  324.098169] SysRq : Show Memory
[  324.099261] active_anon:3793 inactive_anon:1635 isolated_anon:590
[  324.099262]  active_file:1334 inactive_file:4262 isolated_file:0

###3 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 100
Running with 100*40 (== 4000) tasks.
Time: 47.296

  Performance counter stats for 'hackbench 100':

               0  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
            1064  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

    47.765099490  seconds time elapsed

[  454.130625] SysRq : Show Memory
[  454.131718] active_anon:8375 inactive_anon:10350 isolated_anon:10285
[  454.131720]  active_file:1675 inactive_file:7148 isolated_file:30

###4 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 80
Running with 80*40 (== 3200) tasks.
Time: 4.790

  Performance counter stats for 'hackbench 80':

               0  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
               0  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

     5.210933885  seconds time elapsed

[  599.514166] SysRq : Show Memory
[  599.515263] active_anon:27830 inactive_anon:114 isolated_anon:0
[  599.515264]  active_file:1195 inactive_file:3284 isolated_file:0

###5 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 90
Running with 90*40 (== 3600) tasks.
Time: 5.836

  Performance counter stats for 'hackbench 90':

               0  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
               0  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

     6.258902896  seconds time elapsed

[  753.201247] SysRq : Show Memory
[  753.202346] active_anon:37091 inactive_anon:114 isolated_anon:0
[  753.202348]  active_file:1211 inactive_file:3314 isolated_file:0

###6 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 100
Running with 100*40 (== 4000) tasks.
Time: 6.445

  Performance counter stats for 'hackbench 100':

               0  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
               0  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

     6.920834955  seconds time elapsed

[  836.228395] SysRq : Show Memory
[  836.229487] active_anon:30157 inactive_anon:114 isolated_anon:0
[  836.229488]  active_file:1217 inactive_file:3338 isolated_file:0

###7 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 120
Running with 120*40 (== 4800) tasks.
Time: 66.182

  Performance counter stats for 'hackbench 120':

            3307  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
            1218  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

    66.767057051  seconds time elapsed

[  927.855061] SysRq : Show Memory
[  927.856156] active_anon:11320 inactive_anon:11962 isolated_anon:11879
[  927.856157]  active_file:1220 inactive_file:3253 isolated_file:0

###8 run
root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 110
Running with 110*40 (== 4400) tasks.
Time: 47.128

  Performance counter stats for 'hackbench 110':

               6  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
             934  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

    47.657109224  seconds time elapsed

[ 1058.031490] SysRq : Show Memory
[ 1058.032573] active_anon:15351 inactive_anon:245 isolated_anon:23350
[ 1058.032574]  active_file:2112 inactive_file:5036 isolated_file:0

###9 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 100
Running with 100*40 (== 4000) tasks.
Time: 14.223

  Performance counter stats for 'hackbench 100':

               9  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
             382  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

    14.773145947  seconds time elapsed

[ 1242.620748] SysRq : Show Memory
[ 1242.621843] active_anon:5926 inactive_anon:3066 isolated_anon:788
[ 1242.621844]  active_file:1297 inactive_file:3145 isolated_file:0

###10 run

root@kernalhack:~# perf stat --repeat 1 -e kmem:mm_vmscan_nr_taken_zero -e 
kmem:mm_vmscan_nr_taken_nonzero hackbench 110
Running with 110*40 (== 4400) tasks.
Time: 39.346

  Performance counter stats for 'hackbench 110':

             367  kmem:mm_vmscan_nr_taken_zero #      0.000 M/sec
             810  kmem:mm_vmscan_nr_taken_nonzero #      0.000 M/sec

    39.880113992  seconds time elapsed

[ 1346.694702] SysRq : Show Memory
[ 1346.695797] active_anon:12729 inactive_anon:6726 isolated_anon:3804
[ 1346.695798]  active_file:1311 inactive_file:3141 isolated_file:0

Thanks,

Vincent

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