Re: all your slabs are belong to ram ?

["Johannes Truschnigg" <johannes.truschnigg@xxxxxxxxxxx>]

Am Di, 6.10.2015, 16:50 schrieb Darrick J. Wong:
> On Tue, Oct 06, 2015 at 04:24:43PM +0200, krautus@xxxxxxxxx wrote:
>> [...]
>> So I'm asking you:
>> 1. is there a way to force dentries and inodes to stay in ram ?
>> 2. can I perhaps move dentries and inodes to a dedicated SSD ?
>>
>> I'm open to all possibilities, perhaps increase RAM ?
>> Upgrade to Debian Jessie and 64 bit ?
>
> ISTR that kernel data such as slabs cannot live in highmem, which means
> that
> dentries and slab cannot live in highmem.  A 32bit kernel sets up ~900M of
> low
> memory and ~15G of highmem, which is probably why the kernel has to evict
> things and why you see such problems.
>
> A 64bit kernel sets up all the memory as lowmem, so the kernel can use all
> the
> memory for stuff like that.  I'd give that a try first.

A few years back, we solved pretty much that exact same problem by
switching the kernel to amd64, with all of userspace remaining i386. You
should definitely try this.

-- 
Mit freundlichen Grüßen
Johannes Truschnigg
Senior System Administrator
--
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