Bug 159184 - excessive ext3_inode_cache slab usage
excessive ext3_inode_cache slab usage
Status: CLOSED ERRATA
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
3
x86_64 Linux
medium Severity high
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Assigned To: Dave Jones
Brian Brock
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2005-05-31 01:35 EDT by Damian Menscher
Modified: 2015-01-04 17:19 EST (History)
2 users (show)

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Doc Type: Bug Fix
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Last Closed: 2005-09-29 04:16:44 EDT
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Description Damian Menscher 2005-05-31 01:35:46 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050514 Fedora/1.0.4-0.fdr.1.2 Firefox/1.0.4

Description of problem:
An excessive amount of memory is being allocated to the slab for the ext3_inode_cache.  On a machine with 8GB ram and no applications running, free reports 4.5GB of ram in use:

# free
             total       used       free     shared    buffers     cached
Mem:       8079404    6034904    2044500          0     853652     649828
-/+ buffers/cache:    4531424    3547980
Swap:      2096472          0    2096472

The interesting part is from slabtop, though:

 Active / Total Objects (% used)    : 7502225 / 7509918 (99.9%)
 Active / Total Slabs (% used)      : 1120402 / 1120404 (100.0%)
 Active / Total Caches (% used)     : 93 / 131 (71.0%)
 Active / Total Size (% used)       : -305009.98K / -304212.66K (100.3%)
 Minimum / Average / Maximum Object : 0.02K / -0.04K / 128.00K

  OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME                   
3554924 3554923  99%    0.84K 888731        4   3554924K ext3_inode_cache
3585946 3585941  99%    0.23K 210938       17    843752K dentry_cache

Note that it shows 3.5G of ram being used for the ext3_inode_cache.

I believe the memory got used when backups ran (a process that would walk the filesystem tree).  But it hasn't gone down since then (24 hours).  This might be related to Bug 150945, but there people were complaining about a couple hundred meg of slab usage, whereas here it's 3.5G.

Marking as "high" severity since 3.5G memory disappearing constitutes a "severe memory leak" IMHO.

Version-Release number of selected component (if applicable):
kernel-2.6.11-1.27_FC3

How reproducible:
Didn't try

Steps to Reproduce:
1. run a process that walks a large directory tree like du or updatedb

Additional info:
Comment 1 Dave Jones 2005-06-01 01:39:18 EDT
Does this memory get reclaimed if you run something that needs lots of memory ?
This could be perfectly normal, unless it doesn't get reclaimed.
Comment 2 Dave Jones 2005-07-15 14:26:45 EDT
An update has been released for Fedora Core 3 (kernel-2.6.12-1.1372_FC3) which
may contain a fix for your problem.   Please update to this new kernel, and
report whether or not it fixes your problem.

If you have updated to Fedora Core 4 since this bug was opened, and the problem
still occurs with the latest updates for that release, please change the version
field of this bug to 'fc4'.

Thank you.

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