[Intel-gfx] [PATCH] mm: Throttle shrinkers harder

[Dave Hansen]

On 04/22/2014 12:30 PM, Daniel Vetter wrote:
>> > > During testing of i915.ko with working texture sets larger than RAM, we
>> > > encounter OOM with plenty of memory still trapped within writeback, e.g:
>> > > 
>> > > [   42.386039] active_anon:10134 inactive_anon:1900781 isolated_anon:32
>> > >  active_file:33 inactive_file:39 isolated_file:0
>> > >  unevictable:0 dirty:0 writeback:337627 unstable:0
>> > >  free:11985 slab_reclaimable:9458 slab_unreclaimable:23614
>> > >  mapped:41 shmem:1560769 pagetables:1276 bounce:0
>> > > 
>> > > If we throttle for writeback following shrink_slab, this gives us time
>> > > to wait upon the writeback generated by the i915.ko shinker:
>> > > 
>> > > [ 4756.750808] active_anon:24386 inactive_anon:900793 isolated_anon:0
>> > >  active_file:23 inactive_file:20 isolated_file:0
>> > >  unevictable:0 dirty:0 writeback:0 unstable:0
>> > >  free:5550 slab_reclaimable:5184 slab_unreclaimable:4888
>> > >  mapped:3 shmem:472393 pagetables:1249 bounce:0

Could you get some dumps of the entire set of OOM information?  These
are only tiny snippets.

Also, the vmstat output from the bug:

> https://bugs.freedesktop.org/show_bug.cgi?id=72742

shows there being an *AWFUL* lot of swap I/O going on here.  From the
looks of it, we stuck ~2GB in swap and evicted another 1.5GB of page
cache (although I guess that could be double-counting tmpfs getting
swapped out too).  Hmmm, was this one of the cases where you actually
ran _out_ of swap?

>  2  0  19472  33952    296 3610324    0 19472     0 19472 1474  151  3 27 71  0
>  4  0 484964  66468    296 3175864    0 465492     0 465516 2597 1395  0 32 66  2
>  0  2 751940  23692    980 3022884    0 266976   688 266976 3681  636  0 27 66  6
> procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
>  2  1 1244580 295336    988 2606984    0 492896     0 492908 1237  311  1  9 50 41
>  0  2 2047996  28760    988 2037144    0 803160     0 803160 1221 1291  1 15 69 14