[LU-8492] ptlrpc: Correctly calculate hrp->hrp_nthrs

• Status: Resolved
• Project: Lustre
• Fix Version/s: Lustre 2.9.0
• Type: Bug
• Priority: Minor
• Reporter: Joseph Gmitter (Inactive)
• Assignee: Amir Shehata (Inactive)
• Resolution: Fixed
• Severity: 3

Description

This ticket separates out patch http://review.whamcloud.com/#/c/19106/ from LU-6285 was already resolved when the new issue was identified (as noted in LU-6285)

It addresses the following:

There is still an issue which could cause the assert.

cpu_pattern can sepcify exactly 1 cpu in a partition:
"0[0]". That means CPT0 will have CPU 0. CPU 0 can have
hyperthreading enabled. This combination would result in

weight = cfs_cpu_ht_nsiblings(0);
hrp->hrp_nthrs = cfs_cpt_weight(ptlrpc_hr.hr_cpt_table, i);
hrp->hrp_nthrs /= weight;

evaluating to 0. Where

cfs_cpt_weight(ptlrpc_hr.hr_cpt_table, i) == 1
weight == 2

Therefore only divide out with weight if

hrp->hrp_nthrs >= weight

This will avoid the assert:

LASSERT(hrp->hrp_nthrs > 0);

Issue Links

• is related to: LU-6285 Assert fails in staging client module...
• is related to: LU-8451 assert if cpu_pattern specifies exact...

Comments

[Joseph Gmitter (Inactive)]

Patch is http://review.whamcloud.com/#/c/19106/

[Gerrit Updater]

remove incorrect comment

[Doug Oucharek (Inactive)]

Dmitry: does your new patch replace http://review.whamcloud.com/#/c/19106/?

[Dmitry Eremin (Inactive)]

My patch http://review.whamcloud.com/23222 contain this http://review.whamcloud.com/19106 patch.

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch http://review.whamcloud.com/19106/
Subject: LU-8492 ptlrpc: Correctly calculate hrp->hrp_nthrs
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 402825050f95fff80a021e6eb04aa49a210648c9

[Peter Jones]

Landed for 2.9