Jörn Engel wrote:
On Mon, 9 July 2007 09:29:38 +1000, David Chinner wrote:
On Sat, Jul 07, 2007 at 12:45:35PM +0200, Jörn Engel wrote:
Oh certainly! I should dust off my dcache_static patch. Some dentries
are hands-off for the shrinker, basically mountpoints and tmpfs. The
patch moves those to a seperate slab cache.
I doubt there's enough of those to make any difference - putting all
the directories into another slab did little to reduce fragmentation
(~18 months ago we tried that), so I don't think that this would help
at all...
Interesting. I suspect that the de-facto random cache eviction has a
bigger effect and overshadows everything else. So the decisive step
would be to nuke all dentries in a given slab.
It wouldn't surprise me if your patch did make a difference afterwards.
With 32 dentries per slab, it doesn't take many pinned objects to pin
most slabs.
What happened to the patches floating around to stick the dentries for
directories into a different cache? IIRC, they were somewhat problematic
because you don't know what the dentry is used for at allocate time,
but did that ever get fixed / worked around?
M.
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