Re: Large slab cache in 2.6.1

Nick Piggin
2004-02-22T02:39:26Z

Mike Fedyk wrote:

> William Lee Irwin III wrote:
>
>> Mike Fedyk wrote:
>>
>>>> I have 1.5 GB of ram in this system that will be a Linux Terminal
>>>> Server (but using Debian & VNC). There's 600MB+ anonymous memory,
>>>> 600MB+ slab cache, and 100MB page cache. That's after turning off
>>>> swap (it was 400MB into swap at the time).
>>>
>>
>>
>> On Sat, Feb 21, 2004 at 05:09:34PM -0800, Mike Fedyk wrote:
>>
>>> Here's my top slab users:
>>> dentry_cache 585455 763395 256 15 1 : tunables 120
>>> 60 8 : slabdata 50893 50893 3
>>> ext3_inode_cache 686837 688135 512 7 1 : tunables 54
>>> 27 8 : slabdata 98305 98305 0
>>> buffer_head 34095 78078 48 77 1 : tunables 120
>>> 60 8 : slabdata 1014 1014 0
>>> vm_area_struct 42103 44602 64 58 1 : tunables 120
>>> 60 8 : slabdata 769 769 0
>>> pte_chain 20964 43740 128 30 1 : tunables 120
>>> 60 8 : slabdata 1458 1458 0
>>
>>
>>
>> Similar issue here; I ran out of filp's/whatever shortly after booting.
>
>
> So Nick Piggin's VM patches won't help with this?
>

Probably not.

The main thing they do is to try to be smarter about which active
mapped pages to evict. The slab shrinking balance is pretty well
unchanged.

However there is one path in try_to_free_pages that I've changed
to shrink the slab where it otherwise wouldn't. It is pretty
unlikely that would would be continually running into this path,
but testing is welcome, as always.

Stupid question: you didn't actually say what the problem is...
having 600MB slab cache and 400MB swap may not actually be a
problem provided the swap is not being used and the cache is.

I have an idea it might be worthwhile to try using inactive list
scanning as an input to slab pressure...

Nick