[Cluster-devel] [GFS2 PATCH 2/6] GFS2: Check gfs2_rgrp_used_recently inside gfs2_rgrp_congested

[Bob Peterson <rpeterso@redhat.com>]

Hi,

----- Original Message -----
| Hi,
| 
| 
| On 10/01/18 20:42, Bob Peterson wrote:
| > Function gfs2_rgrp_congested is called in two places: once before
| > we acquire the rgrp glock, and once after. The first time, it checks
| > to see if the rgrp was used recently because the usage statistics
| > are only valid in short-term. For the second call, that check was
| > not done, but should have been, for the same reason.
| >
| > This patch simply moves function gfs2_rgrp_used_recently before
| > function gfs2_rgrp_congested, and it's now called from there so
| > it applies equally to both checks.
| I don't think this makes sense. The purpose of the
| gfs2_rgrp_used_recently test is that when we don't hold the glock we
| might not have up to date stats to make decisions from, so we check that
| we've held the lock recently enough that we can use historical
| statistics. Once we hold the lock however, then we can be sure that the
| stats are up to date, as the process of acquiring the lock will bring
| them up to date, so why repeat the test when we already have the lock?
| 
| Steve.

Hm. I'll admit it's been a long time since I revisited this patch set,
but you've got a valid point. This makes no sense. I'll pull this patch.

Bob Peterson
Red Hat File Systems