[LU-12394] lctl get_param llite.lfs*.extents_stats only displays first two buckets

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.13.0, Lustre 2.12.3
• Severity: 3
• Assignee: Patrick Farrell (Inactive)
• Reporter: Patrick Farrell (Inactive)

Description

ll_extent_stats is broken on recent versions, displaying on the 0-4K and 4K - 8K buckets:

lctl get_param llite.*.extents_stats
llite.[...].extents_stats=
snapshot_time:         1559766954.651554186 (secs.nsecs)
                               read       |                write
      extents            calls    % cum%  |          calls    % cum%
   0K -    4K :              0    0    0  |              0    0    0
   4K -    8K :              0    0    0  |         207590  100  100 

This was broken in:

commit adb5aca3d67380078c4bd35c74651a7b9f848f4d
Author: James Simmons <[e-mail]>
Date: Sat Oct 13 15:24:46 2018 -0400

LU-8066 llite: Move all remaining procfs entries to debugfs

This moves all remaining procfs handling in llite layer to debugfs.

This is a modified version of

Linux-commit : ae7c0f4833a65b7648cceaf1a60503a89e057f0f

Change-Id: Id5c411d21a660a17a015ca9976b857e6b088c28a
Signed-off-by: Dmitry Eremin <[e-mail]>
Signed-off-by: Oleg Drokin <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: James Simmons <[e-mail]>
Reviewed-on: https://review.whamcloud.com/32517
Tested-by: Jenkins
Tested-by: Maloo <[e-mail]>
Reviewed-by: Andreas Dilger <[e-mail]>
Reviewed-by: Ben Evans <[e-mail]>
Reviewed-by: Oleg Drokin <[e-mail]>

By this change:

-        for(i = 0; (count >= (1 << LL_HIST_START << i)) &&
+       for(i = 0; (count >= BIT(LL_HIST_START << i)) && 

BIT(LL_HIST_START << i) is not actually the same as 1 << LL_HIST_START << i due to operation ordering details.

BIT(LL_HIST_START + i) gives the desired behavior.