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| author | Breno Leitao <leitao@debian.org> | 2026-05-11 05:26:55 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-05-11 08:58:23 -1000 |
| commit | 1503043fd75e29ad49c7d506232e272f6951d07d (patch) | |
| tree | 995dabebe4709799103fbc22c928153a1939fce5 /lib/Kconfig.debug | |
| parent | dfca46365afc030fb09bb40226514c500202dcdc (diff) | |
| download | linux-next-1503043fd75e29ad49c7d506232e272f6951d07d.tar.gz linux-next-1503043fd75e29ad49c7d506232e272f6951d07d.zip | |
workqueue: forbid TEST_WORKQUEUE from being built-in
The benchmark drives the workqueue's affinity_scope through sysfs by
filp_open()'ing /sys/bus/workqueue/devices/bench_wq/affinity_scope. When
CONFIG_TEST_WORKQUEUE=y, the module_init runs during kernel init before
userspace has mounted sysfs, so every open returns -ENOENT and the
benchmark loop spins emitting:
test_workqueue: open /sys/bus/workqueue/devices/bench_wq/affinity_scope failed: -2
Mirror the TEST_BPF pattern and add "depends on m" so Kconfig will not
let this be built into the kernel image, and document the reason in the
help text.
Fixes: 24b2e73f9700 ("workqueue: add test_workqueue benchmark module")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'lib/Kconfig.debug')
| -rw-r--r-- | lib/Kconfig.debug | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8ff5adcfe1e0..040f4e077435 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2649,12 +2649,17 @@ config TEST_VMALLOC config TEST_WORKQUEUE tristate "Test module for stress/performance analysis of workqueue" + depends on m default n help This builds the "test_workqueue" module for benchmarking workqueue throughput under contention. Useful for evaluating affinity scope changes (e.g., cache_shard vs cache). + The test drives sysfs to switch affinity scopes, so it must be + loaded after userspace has mounted sysfs; building it in (=y) + would run module_init before /sys is available. + If unsure, say N. config TEST_BPF |