On Thu, Jul 18, 2013 at 3:47 PM, Akemi Yagi amyagi@gmail.com wrote:
On Thu, Jul 18, 2013 at 2:07 PM, Karanbir Singh mail-lists@karan.org wrote:
Which then has me thinking - what is the actual problem we are trying to solve here ? and how can I ratify that ?
All details are given in CentOS bug #6548 (links therein) but here's is a short summary of the events that were seen in the kernel development [list].
Someone reported "bad performance with SSD since kernel version 2.6.32". After bisection, he found the following commit to be the likely culprit:
commit fb1e75389bd06fd5987e9cda1b4e0305c782f854 Author: Jens Axboe jens.axboe@xxxxxxxxxx Date: Thu Jul 30 08:18:24 2009 +0200 (This was added to kernel 2.6.32)
Long story short, this commit was reverted in kernel 2.6.33:
commit 79da0644a8e0838522828f106e4049639eea6baf Author: Jens Axboe jens.axboe@oracle.com Date: Tue Feb 23 08:40:43 2010 +0100
(snip)
Just wanted to update the status of the issue.
(1) Current centosplus kernel 2.6.32-358.18.1.el6.centos.plus has the patch from the second commit quoted above that is supposed to rectify the issue.
(2) I've filed a bug report upstream:
https://bugzilla.redhat.com/show_bug.cgi?id=1003678 (It's marked private)
From the way it looks, the patch will be pulled in to the RHEL kernel
but no specific version is given.
Akemi