[DOCS-5108] Comment on: "manual/reference/transparent-huge-pages.txt" Created: 25/Mar/15  Updated: 11/Jan/17  Resolved: 07/Aug/15

Status: Closed
Project: Documentation
Component/s: None
Affects Version/s: None
Fix Version/s: 01112017-cleanup

Type: Bug Priority: Major - P3
Reporter: Docs Collector User (Inactive) Assignee: Unassigned
Resolution: Duplicate Votes: 0
Labels: collector-298ba4e7
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified
Environment:

Linux mint debian edition
uname -a :
3.11-2-amd64 #1 SMP Debian 3.11.8-1 (2013-11-13) x86_64 GNU/Linux

Location: http://docs.mongodb.org/manual/reference/transparent-huge-pages/
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.50 Safari/537.36
Referrer: http://docs.mongodb.org/manual/administration/production-notes/
Screen Resolution: 1920 x 1080
repo: docs
source: reference/transparent-huge-pages


Issue Links:
Duplicate
duplicates DOCS-5330 Using /etc/rc.local to disable THP re... Closed
Participants:
Days since reply: 7 years, 29 weeks ago

 Description   

Hi,

As we can see here, there is now a double check on Transparent Huge Page:
https://jira.mongodb.org/browse/SERVER-16643?focusedCommentId=805628&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-805628

But When I use the 'In boot Time Configuration' suggestion, only transparent_hugepage/enable is set to never

From Transparent Huge Page documentation :

== Boot parameter ==

You can change the sysfs boot time defaults of Transparent Hugepage
Support by passing the parameter "transparent_hugepage=always" or
"transparent_hugepage=madvise" or "transparent_hugepage=never"
(without "") to the kernel command line.
https://www.kernel.org/doc/Documentation/vm/transhuge.txt

Because of that I still got a warning when running mongo on transparent_hugepage/defrag. Because of that, I think either the first solution is incomplete, or not adequate.

Thank's for reading !



 Comments   
Comment by Emily Hall [ 27/Jul/16 ]

Closed for housekeeping on 7/27/2016 by Emily Hall.
If you require additional support, please open a new ticket for prioritization.
Thanks,
Emily

Comment by Kay Kim (Inactive) [ 07/Aug/15 ]

Duplicate of DOCS-5330

Comment by Max Polk [ 05/May/15 ]

Verified that the defrag is examined without regard to the enabled:

$ cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]
$ cat /sys/kernel/mm/transparent_hugepage/defrag
[always] madvise never
$ service mongod start
... (in log) WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'
$ echo 'never' > /sys/kernel/mm/transparent_hugepage/defrag
$ cat /sys/kernel/mm/transparent_hugepage/defrag
always madvise [never]
$ service mongod stop
$ service mongod start
... (no warning in log)

Therefore, the fix to this bug is to first look at transparent_hugepage/enabled, and if it is never, don't bother looking at the irrelevant transparent_hugepage/defrag setting.

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