linux-kernel - Re: Unbounded growth of slab caches and how to shrink them

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Message-ID: <alpine.DEB.2.20.1606290933010.15414@east.gentwo.org>
Date:	Wed, 29 Jun 2016 09:34:38 -0500 (CDT)
From:	Christoph Lameter <cl@...ux.com>
To:	Nikolay Borisov <kernel@...p.com>
cc:	"Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>
Subject: Re: Unbounded growth of slab caches and how to shrink them

On Wed, 29 Jun 2016, Nikolay Borisov wrote:

> Right, so what debugging concretely do you have in mind. So far what I
> did was reboot the machine with SLUB merging disabled, since there are
> quite a lot of slabs being merged into that particular one:
>
> :t-0000192   <- cred_jar pid_3 inet_peer_cache request_sock_TCPv6
> kmalloc-192 file_lock_cache bio-0 ip_dst_cache key_jar
>
> I'm quite sure it's likely it's one of the either networking or bio-0
> slab cache, since the others seems generally not very used.

Reboot the box with "slub_debug" on the kernel command line. Then post
the output of /sys/kernel/slab/kmalloc-128/alloc_calls and free_call after
you have recreated the situation.