Merge branch 'net-dqs-optimize-if-stall-threshold-is-not-set'

Merge branch 'net-dqs-optimize-if-stall-threshold-is-not-set'

Breno Leitao says:

====================
net: dqs: optimize if stall threshold is not set

Here are four patches aimed at enhancing the Dynamic Queue Limit (DQL)
subsystem within the networking stack.

The first two commits involve code refactoring, while the third patch
introduces the actual change. The fourth patch just improves the cache
locality.

Typically, when DQL is enabled, stall information is always populated
through dql_queue_stall(). However, this information is only necessary
if a stall threshold is set, which is stored in struct dql->stall_thrs.

Although dql_queue_stall() is relatively inexpensive, it is not entirely
free due to memory barriers and similar overheads.

To optimize performance, refrain from calling dql_queue_stall() when no
stall threshold is set, thus avoiding the processing of unnecessary
information.

v1: https://lore.kernel.org/all/20240404145939.3601097-1-leitao@debian.org/
====================

Link: https://lore.kernel.org/r/20240411192241.2498631-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>