Since commit c66d4bd110a1f8 ("genirq/affinity: Add new callback for
(re)calculating interrupt sets"), irq_create_affinity_masks() returns
NULL in case of single vector. This change has caused regression on some
drivers, such as lpfc.
The problem is that single vector may be triggered in some generic cases:
1) kdump kernel 2) irq vectors resource is close to exhaustion.
If we don't create affinity mask for single vector, almost every caller
has to handle the special case.
So still create affinity mask for single vector, since irq_create_affinity_masks()
is capable of handling that.
Cc: Marc Zyngier <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: [email protected]
Cc: Sagi Grimberg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Keith Busch <[email protected]>
Cc: Sumit Saxena <[email protected]>
Cc: Kashyap Desai <[email protected]>
Cc: Shivasharan Srikanteshwara <[email protected]>
Fixes: c66d4bd110a1f8 ("genirq/affinity: Add new callback for (re)calculating interrupt sets")
Signed-off-by: Ming Lei <[email protected]>
---
kernel/irq/affinity.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 4352b08ae48d..6fef48033f96 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -251,11 +251,9 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
* Determine the number of vectors which need interrupt affinities
* assigned. If the pre/post request exhausts the available vectors
* then nothing to do here except for invoking the calc_sets()
- * callback so the device driver can adjust to the situation. If there
- * is only a single vector, then managing the queue is pointless as
- * well.
+ * callback so the device driver can adjust to the situation.
*/
- if (nvecs > 1 && nvecs > affd->pre_vectors + affd->post_vectors)
+ if (nvecs > affd->pre_vectors + affd->post_vectors)
affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
else
affvecs = 0;
--
2.20.1
Hello Thomas and Guys,
On Mon, Aug 5, 2019 at 9:19 AM Ming Lei <[email protected]> wrote:
>
> Since commit c66d4bd110a1f8 ("genirq/affinity: Add new callback for
> (re)calculating interrupt sets"), irq_create_affinity_masks() returns
> NULL in case of single vector. This change has caused regression on some
> drivers, such as lpfc.
>
> The problem is that single vector may be triggered in some generic cases:
> 1) kdump kernel 2) irq vectors resource is close to exhaustion.
>
> If we don't create affinity mask for single vector, almost every caller
> has to handle the special case.
>
> So still create affinity mask for single vector, since irq_create_affinity_masks()
> is capable of handling that.
>
> Cc: Marc Zyngier <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Bjorn Helgaas <[email protected]>
> Cc: Jens Axboe <[email protected]>
> Cc: [email protected]
> Cc: Sagi Grimberg <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: Keith Busch <[email protected]>
> Cc: Sumit Saxena <[email protected]>
> Cc: Kashyap Desai <[email protected]>
> Cc: Shivasharan Srikanteshwara <[email protected]>
> Fixes: c66d4bd110a1f8 ("genirq/affinity: Add new callback for (re)calculating interrupt sets")
> Signed-off-by: Ming Lei <[email protected]>
> ---
> kernel/irq/affinity.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index 4352b08ae48d..6fef48033f96 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -251,11 +251,9 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
> * Determine the number of vectors which need interrupt affinities
> * assigned. If the pre/post request exhausts the available vectors
> * then nothing to do here except for invoking the calc_sets()
> - * callback so the device driver can adjust to the situation. If there
> - * is only a single vector, then managing the queue is pointless as
> - * well.
> + * callback so the device driver can adjust to the situation.
> */
> - if (nvecs > 1 && nvecs > affd->pre_vectors + affd->post_vectors)
> + if (nvecs > affd->pre_vectors + affd->post_vectors)
> affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
> else
> affvecs = 0;
Without this patch, kdump kernel may not work, so could you take a look
at this patch?
Thanks,
Ming Lei
Commit-ID: 491beed3b102b6e6c0e7734200661242226e3933
Gitweb: https://git.kernel.org/tip/491beed3b102b6e6c0e7734200661242226e3933
Author: Ming Lei <[email protected]>
AuthorDate: Mon, 5 Aug 2019 09:19:06 +0800
Committer: Thomas Gleixner <[email protected]>
CommitDate: Thu, 8 Aug 2019 08:47:55 +0200
genirq/affinity: Create affinity mask for single vector
Since commit c66d4bd110a1f8 ("genirq/affinity: Add new callback for
(re)calculating interrupt sets"), irq_create_affinity_masks() returns
NULL in case of single vector. This change has caused regression on some
drivers, such as lpfc.
The problem is that single vector requests can happen in some generic cases:
1) kdump kernel
2) irq vectors resource is close to exhaustion.
If in that situation the affinity mask for a single vector is not created,
every caller has to handle the special case.
There is no reason why the mask cannot be created, so remove the check for
a single vector and create the mask.
Fixes: c66d4bd110a1f8 ("genirq/affinity: Add new callback for (re)calculating interrupt sets")
Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/irq/affinity.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 4352b08ae48d..6fef48033f96 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -251,11 +251,9 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
* Determine the number of vectors which need interrupt affinities
* assigned. If the pre/post request exhausts the available vectors
* then nothing to do here except for invoking the calc_sets()
- * callback so the device driver can adjust to the situation. If there
- * is only a single vector, then managing the queue is pointless as
- * well.
+ * callback so the device driver can adjust to the situation.
*/
- if (nvecs > 1 && nvecs > affd->pre_vectors + affd->post_vectors)
+ if (nvecs > affd->pre_vectors + affd->post_vectors)
affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
else
affvecs = 0;
On Mon, Aug 05, 2019 at 09:19:06AM +0800, Ming Lei wrote:
> Since commit c66d4bd110a1f8 ("genirq/affinity: Add new callback for
> (re)calculating interrupt sets"), irq_create_affinity_masks() returns
> NULL in case of single vector. This change has caused regression on some
> drivers, such as lpfc.
>
> The problem is that single vector may be triggered in some generic cases:
> 1) kdump kernel 2) irq vectors resource is close to exhaustion.
>
> If we don't create affinity mask for single vector, almost every caller
> has to handle the special case.
>
> So still create affinity mask for single vector, since irq_create_affinity_masks()
> is capable of handling that.
Hi Ming,
Looks good to me.
Reviewed-by: Keith Busch <[email protected]>
> ---
> kernel/irq/affinity.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> index 4352b08ae48d..6fef48033f96 100644
> --- a/kernel/irq/affinity.c
> +++ b/kernel/irq/affinity.c
> @@ -251,11 +251,9 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
> * Determine the number of vectors which need interrupt affinities
> * assigned. If the pre/post request exhausts the available vectors
> * then nothing to do here except for invoking the calc_sets()
> - * callback so the device driver can adjust to the situation. If there
> - * is only a single vector, then managing the queue is pointless as
> - * well.
> + * callback so the device driver can adjust to the situation.
> */
> - if (nvecs > 1 && nvecs > affd->pre_vectors + affd->post_vectors)
> + if (nvecs > affd->pre_vectors + affd->post_vectors)
> affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
> else
> affvecs = 0;
> --