| Message ID | 20220718192844.1805158-10-yury.norov@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Introduce DEBUG_BITMAP config option and bitmap_check_params() | expand |
On Mon, Jul 18, 2022 at 12:28:37PM -0700, Yury Norov wrote: > kernel/irq/manage.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c > index 8c396319d5ac..f9c1b21584ec 100644 > --- a/kernel/irq/manage.c > +++ b/kernel/irq/manage.c > @@ -284,7 +284,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, > switch (ret) { > case IRQ_SET_MASK_OK: > case IRQ_SET_MASK_OK_DONE: > - cpumask_copy(desc->irq_common_data.affinity, mask); > + if (desc->irq_common_data.affinity != mask) > + cpumask_copy(desc->irq_common_data.affinity, mask); Seems like mostly pointless logic at this point. This is not a performance senstive operation afaik. > fallthrough; > case IRQ_SET_MASK_OK_NOCOPY: > irq_validate_effective_affinity(data); > -- > 2.34.1 >
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 8c396319d5ac..f9c1b21584ec 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -284,7 +284,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, switch (ret) { case IRQ_SET_MASK_OK: case IRQ_SET_MASK_OK_DONE: - cpumask_copy(desc->irq_common_data.affinity, mask); + if (desc->irq_common_data.affinity != mask) + cpumask_copy(desc->irq_common_data.affinity, mask); fallthrough; case IRQ_SET_MASK_OK_NOCOPY: irq_validate_effective_affinity(data);
irq_do_set_affinity() may be called with mask == irq_data_to_desc()->irq_common_data.affinity Copying in that case is useless. Caught with CONFIG_DEBUG_BITMAP: [ 1.089177] __bitmap_check_params+0x144/0x250 [ 1.089238] irq_do_set_affinity+0x120/0x470 [ 1.089298] irq_startup+0x140/0x16c [ 1.089350] __setup_irq+0x668/0x760 [ 1.089402] request_threaded_irq+0xe8/0x1b0 [ 1.089474] vp_find_vqs_msix+0x270/0x410 [ 1.089532] vp_find_vqs+0x48/0x1b4 [ 1.089584] vp_modern_find_vqs+0x1c/0x70 [ 1.089641] init_vq+0x2dc/0x34c [ 1.089690] virtblk_probe+0xdc/0x710 [ 1.089745] virtio_dev_probe+0x19c/0x270 [ 1.089802] really_probe.part.0+0x9c/0x2ac [ 1.089863] __driver_probe_device+0x98/0x144 [ 1.089923] driver_probe_device+0xac/0x140 [ 1.089985] __driver_attach+0xf8/0x1a0 [ 1.090047] bus_for_each_dev+0x70/0xd0 [ 1.090101] driver_attach+0x24/0x30 [ 1.090153] bus_add_driver+0x150/0x200 [ 1.090208] driver_register+0x78/0x130 [ 1.090266] register_virtio_driver+0x28/0x40 [ 1.090329] virtio_blk_init+0x68/0xa4 [ 1.090400] do_one_initcall+0x50/0x1c0 [ 1.090471] kernel_init_freeable+0x208/0x28c [ 1.090538] kernel_init+0x28/0x13c [ 1.090590] ret_from_fork+0x10/0x20 [ 1.090642] ---[ end trace 0000000000000000 ]--- [ 1.090705] b1: ffff2ec742b85e18 [ 1.090710] b2: ffff2ec742b85e18 [ 1.090715] b3: 0 [ 1.090719] nbits: 256 [ 1.090723] start: 0 [ 1.090727] off: 0 Signed-off-by: Yury Norov <yury.norov@gmail.com> --- kernel/irq/manage.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)