Re: drop_caches ...

Markus
2009-03-04T18:47:48Z

Am Mittwoch, 4. März 2009 schrieb Zdenek Kabelac:
> Markus napsal(a):
> >>>>>>> The memory mapped pages won't be dropped in this way.
> >>>>>>> "cat /proc/meminfo" will show you the number of mapped pages.
> >>>>>> # sync ; echo 3 > /proc/sys/vm/drop_caches ; free -m ;
> >>>> cat /proc/meminfo
> >>>>>> total used free shared buffers
> >>>>>> cached
> >>>>>> Mem: 3950 3262 688 0 0
> >>>>>> 359
> >>>>>> -/+ buffers/cache: 2902 1047
> >>>>>> Swap: 5890 1509 4381
> >>>>>> MemTotal: 4045500 kB
> >>>>>> MemFree: 705180 kB
> >>>>>> Buffers: 508 kB
> >>>>>> Cached: 367748 kB
> >>>>>> SwapCached: 880744 kB
> >>>>>> Active: 1555032 kB
> >>>>>> Inactive: 1634868 kB
> >>>>>> Active(anon): 1527100 kB
> >>>>>> Inactive(anon): 1607328 kB
> >>>>>> Active(file): 27932 kB
> >>>>>> Inactive(file): 27540 kB
> >>>>>> Unevictable: 816 kB
> >>>>>> Mlocked: 0 kB
> >>>>>> SwapTotal: 6032344 kB
> >>>>>> SwapFree: 4486496 kB
> >>>>>> Dirty: 0 kB
> >>>>>> Writeback: 0 kB
> >>>>>> AnonPages: 2378112 kB
> >>>>>> Mapped: 52196 kB
> >>>>>> Slab: 65640 kB
> >>>>>> SReclaimable: 46192 kB
> >>>>>> SUnreclaim: 19448 kB
> >>>>>> PageTables: 28200 kB
> >>>>>> NFS_Unstable: 0 kB
> >>>>>> Bounce: 0 kB
> >>>>>> WritebackTmp: 0 kB
> >>>>>> CommitLimit: 8055092 kB
> >>>>>> Committed_AS: 4915636 kB
> >>>>>> VmallocTotal: 34359738367 kB
> >>>>>> VmallocUsed: 44580 kB
> >>>>>> VmallocChunk: 34359677239 kB
> >>>>>> DirectMap4k: 3182528 kB
> >>>>>> DirectMap2M: 1011712 kB
> >>>>>>
> >>>>>> The cached reduced to 359 MB (after the dropping).
> >>>>>> I dont know where to read the "number of mapped pages".
> >>>>>> "Mapped" is about 51 MB.
> >>>>> Does your tmpfs store lots of files?
> >>>> Dont think so:
> >>>>
> >>>> # df -h
> >>>> Filesystem Size Used Avail Use% Mounted on
> >>>> /dev/md6 14G 8.2G 5.6G 60% /
> >>>> udev 10M 304K 9.8M 3% /dev
> >>>> cachedir 4.0M 100K 4.0M 3% /lib64/splash/cache
> >>>> /dev/md4 19G 15G 3.1G 83% /home
> >>>> /dev/md3 8.3G 4.5G 3.9G 55% /usr/portage
> >>>> shm 2.0G 0 2.0G 0% /dev/shm
> >>>> /dev/md1 99M 19M 76M 20% /boot
> >>>>
> >>>> I dont know what exactly all that memory is used for. It varies
> > from
> >>>> about 300 MB to up to one GB.
> >>>> Tell me where to look and I will!
> >>> So you don't have lots of mapped pages(Mapped=51M) or tmpfs files.
> > It's
> >>> strange to me that there are so many undroppable cached
> > pages(Cached=359M),
> >>> and most of them lie out of the LRU queue(Active+Inactive
> > file=53M)...
> >>> Anyone have better clues on these 'hidden' pages?
> >> Maybe try this:
> >>
> >> cat /proc/`pidof X`/smaps | grep drm | wc -l
> >>
> >> you will see some growing numbers.
> >>
> >> Also check cat /proc/dri/0/gem_objects
> >> there should be some number # object bytes - which should be close
to
> > your
> >> missing cached pages.
> >>
> >>
> >> If you are using Intel GEM driver - there is some unlimited caching
> > issue
> >> see: http://bugs.freedesktop.org/show_bug.cgi?id=20404
> >>
> > # cat /proc/`pidof X`/smaps | grep drm | wc -l
> > 0
> > # cat /proc/dri/0/gem_objects
> > cat: /proc/dri/0/gem_objects: No such file or directory
> >
> > I use Xorg 1.3 with an nvidia gpu. Dont know if I use a "Intel GEM
> > driver".
> >
>
>
> Are you using binary driver from NVidia ??
> Maybe you should ask authors of this binary blob ?
>
> Could you try to use for a while Vesa driver to see, if you are able
to get
> same strange results ?

I rebooted in console without the nvidia-module loaded and have the same
results (updated to 2.6.28.7 btw):
# sync ; echo 3 > /proc/sys/vm/drop_caches ; free -m ; cat /proc/meminfo
total used free shared buffers
cached
Mem: 3950 1647 2303 0 0
924
-/+ buffers/cache: 722 3228
Swap: 5890 0 5890
MemTotal: 4045444 kB
MemFree: 2358944 kB
Buffers: 544 kB
Cached: 946624 kB
SwapCached: 0 kB
Active: 1614756 kB
Inactive: 7632 kB
Active(anon): 1602476 kB
Inactive(anon): 0 kB
Active(file): 12280 kB
Inactive(file): 7632 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 6032344 kB
SwapFree: 6032344 kB
Dirty: 72 kB
Writeback: 32 kB
AnonPages: 675224 kB
Mapped: 17756 kB
Slab: 19936 kB
SReclaimable: 9652 kB
SUnreclaim: 10284 kB
PageTables: 8296 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 8055064 kB
Committed_AS: 3648088 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 10616 kB
VmallocChunk: 34359716459 kB
DirectMap4k: 6080 kB
DirectMap2M: 4188160 kB

Thanks!
Markus