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| author | Tejun Heo <tj@kernel.org> | 2024-04-22 14:43:48 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2024-04-23 17:32:59 -1000 |
| commit | d40f92020c7a225b77e68599e4b099a4a0823408 (patch) | |
| tree | d514c8ac3c00a85d600304a6e858d064bcd62e78 | |
| parent | 57a01eafdcf78f6da34fad9ff075ed5dfdd9f420 (diff) | |
| download | lwn-d40f92020c7a225b77e68599e4b099a4a0823408.tar.gz lwn-d40f92020c7a225b77e68599e4b099a4a0823408.zip | |
workqueue: The default node_nr_active should have its max set to max_active
The default nna (node_nr_active) is used when the pool isn't tied to a
specific NUMA node. This can happen in the following cases:
1. On NUMA, if per-node pwq init failure and the fallback pwq is used.
2. On NUMA, if a pool is configured to span multiple nodes.
3. On single node setups.
5797b1c18919 ("workqueue: Implement system-wide nr_active enforcement for
unbound workqueues") set the default nna->max to min_active because only #1
was being considered. For #2 and #3, using min_active means that the max
concurrency in normal operation is pushed down to min_active which is
currently 8, which can obviously lead to performance issues.
exact value nna->max is set to doesn't really matter. #2 can only happen if
the workqueue is intentionally configured to ignore NUMA boundaries and
there's no good way to distribute max_active in this case. #3 is the default
behavior on single node machines.
Let's set it the default nna->max to max_active. This fixes the artificially
lowered concurrency problem on single node machines and shouldn't hurt
anything for other cases.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 5797b1c18919 ("workqueue: Implement system-wide nr_active enforcement for unbound workqueues")
Link: https://lore.kernel.org/dm-devel/20240410084531.2134621-1-shinichiro.kawasaki@wdc.com/
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | kernel/workqueue.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index a2af0aaf026b..5f536c63a48d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1610,7 +1610,7 @@ static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu) min_active, max_active); } - wq_node_nr_active(wq, NUMA_NO_NODE)->max = min_active; + wq_node_nr_active(wq, NUMA_NO_NODE)->max = max_active; } /** |