[LU-905] keep BH reference on root node of IAM container

• Type: Improvement
• Resolution: Duplicate
• Priority: Minor
• Fix Version/s: Lustre 2.2.0
• Affects Version/s: Lustre 2.2.0
• Story Points: 3
• Assignee: Liang Zhen (Inactive)
• Reporter: Liang Zhen (Inactive)

Description

IAM in ldiskfs-osd will always consume some slots in BH LRU (see: fs/buffer.c), if we keep buffer_head reference on root node, we can save one slot in BH LRU and could be somehow helpful for overall performance, I did some tests, LRU hits rate increased 5%-10% while creating files if we always keep this reference.

Issue Links

• Trackbacks: Changelog 2.2 version 2.2.0 Support for networks: o2iblnd OFED 1.5.4 Server support for kernels: 2.6.32220.4.2.el6 (RHEL6) Client support for unpatched kernels: 2.6.18274.18.1.el5 (RHEL5) 2.6.32220.4.2.el6 (RHEL6) 2.6.32.360....