Re: [Bug #12210] 2.6.28-rc8 big regression in VM

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

Hi,

> Hello,
> 
> you may remember that I reported regression in VM. I used you filecache module
> and discovered that the leaks are caused by these items:
> # filecache 1.0
> #      ino       size   cached cached% refcnt state dev          file
>     167302         16       16     100      1    d- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167301         16       16     100      1    d- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167300         16       16     100      1    d- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167299          4        4     100      1    -- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167290          8        8     100      1    -- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167289          8        8     100      1    -- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167288         16       16     100      1    -- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
>     167287         16       16     100      1    d- 00:08(tmpfs) /drm\040mm\040object\040(deleted)
> 
> there are tons of those items:
> cat /proc/filecache  | grep drm | wc -l
> 14224
> 
> Do you have any clues what happens here? Is it a bug in kernel VM system or it
> is more likely a bug in Intel's GEM drm driver? Right now it results in 500MB
> of undropable cache.
> 
> Also lsof reports many leaked file descriptors:
> lsof | grep drm | wc -l
> 7326

lsof output indicate any process don't close this files.
I would like to hear drm driver developer's opinion.
if many mapped file is unclosed, it seems misdesigned memory wasting.