Bug 819922 - Dentry and innodes shows an alarming increase
Dentry and innodes shows an alarming increase
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel (Show other bugs)
x86_64 Linux
unspecified Severity urgent
: rc
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Assigned To: Red Hat Kernel Manager
Red Hat Kernel QE team
Depends On:
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Reported: 2012-05-08 11:57 EDT by coder43v3r
Modified: 2012-05-09 14:31 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2012-05-09 14:31:41 EDT
Type: Bug
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Description coder43v3r 2012-05-08 11:57:15 EDT
Description of problem:

I am running a CentOS 6.2 64 bit on top of VMWare ESXi 5, the dedicated server is a Dell dual Xeon with 32 giga of memory.
When the server is idle, load is 0, the dentry and innodes rises and rises and gets to a point of slowing down the server and OOM kicks in.
slabtop shows that dentry is rising and that the kernel never frees this memory for other applications.
When i do a free -m and look at the -/+ buffers/caches line, the line that tells how much applications are using real memory, the entry is rising and reflects the dentry leak.
When i try to do a:  sync & echo 2 > /proc/sys/vm/drop_caches  the echo gets stuck in an endless loop in the kernel, as a zombie, taking 100% cpu, and i can not kill it in any way, the only thing left to do is a restart.

Version-Release number of selected component (if applicable):
kernel version: 2.6.32-220.13.1.el6.x86_64
CentOS version: 6.2

How reproducible:
Install CentOS 6.2 on top of VMWare ESXi 5

Steps to Reproduce:
1. Just install
Actual results:
running free -m and examining the -/+ caches/buffers line shows a steady increase.
running slabtop shows a steady and alarming increase in dentry size.

Expected results:
There should be no reason for dentry cache to increase so alarmingly on an idle server, i know all the claims about Linux is taking as much RAM... and it will give it back... but that is not the case ! this leads to slow server and OOM.

Additional info:
I know that i am not using REHL, but CentOS kernel is using REHL kernel and they are the same.
Comment 2 Ric Wheeler 2012-05-09 14:31:41 EDT
Red Hat bugzilla is a support tool for customers - you should take the issue to the upstream kernel lists or community when you are self supporting.

For community support, it is best to reproduce on a recent upstream kernel (i.e., not on CentOS).

Good luck!

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