On 24/04/2020 17:59, Jason Gunthorpe wrote:
> On Mon, Apr 20, 2020 at 09:22:12AM +0300, Gal Pressman wrote:
>> Add a new stat that counts mmap failures, which might help when
>> debugging different issues.
>>
>> Reviewed-by: Firas JahJah <firasj@xxxxxxxxxx>
>> Reviewed-by: Yossi Leybovich <sleybo@xxxxxxxxxx>
>> Signed-off-by: Gal Pressman <galpress@xxxxxxxxxx>
>> drivers/infiniband/hw/efa/efa.h | 3 ++-
>> drivers/infiniband/hw/efa/efa_verbs.c | 9 +++++++--
>> 2 files changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/infiniband/hw/efa/efa.h b/drivers/infiniband/hw/efa/efa.h
>> index aa7396a1588a..77c9ff798117 100644
>> +++ b/drivers/infiniband/hw/efa/efa.h
>> @@ -1,6 +1,6 @@
>> /* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
>> /*
>> - * Copyright 2018-2019 Amazon.com, Inc. or its affiliates. All rights reserved.
>> + * Copyright 2018-2020 Amazon.com, Inc. or its affiliates. All rights reserved.
>> */
>>
>> #ifndef _EFA_H_
>> @@ -40,6 +40,7 @@ struct efa_sw_stats {
>> atomic64_t reg_mr_err;
>> atomic64_t alloc_ucontext_err;
>> atomic64_t create_ah_err;
>> + atomic64_t mmap_err;
>> };
>>
>> /* Don't use anything other than atomic64 */
>> diff --git a/drivers/infiniband/hw/efa/efa_verbs.c b/drivers/infiniband/hw/efa/efa_verbs.c
>> index b555845d6c14..75eef1ec2474 100644
>> +++ b/drivers/infiniband/hw/efa/efa_verbs.c
>> @@ -44,7 +44,8 @@ struct efa_user_mmap_entry {
>> op(EFA_CREATE_CQ_ERR, "create_cq_err") \
>> op(EFA_REG_MR_ERR, "reg_mr_err") \
>> op(EFA_ALLOC_UCONTEXT_ERR, "alloc_ucontext_err") \
>> - op(EFA_CREATE_AH_ERR, "create_ah_err")
>> + op(EFA_CREATE_AH_ERR, "create_ah_err") \
>> + op(EFA_MMAP_ERR, "mmap_err")
>>
>> #define EFA_STATS_ENUM(ename, name) ename,
>> #define EFA_STATS_STR(ename, name) [ename] = name,
>> @@ -1569,6 +1570,7 @@ static int __efa_mmap(struct efa_dev *dev, struct efa_ucontext *ucontext,
>> ibdev_dbg(&dev->ibdev,
>> "pgoff[%#lx] does not have valid entry\n",
>> vma->vm_pgoff);
>> + atomic64_inc(&dev->stats.sw_stats.mmap_err);
>> return -EINVAL;
>> }
>> entry = to_emmap(rdma_entry);
>> @@ -1604,12 +1606,14 @@ static int __efa_mmap(struct efa_dev *dev, struct efa_ucontext *ucontext,
>> err = -EINVAL;
>> }
>>
>> - if (err)
>> + if (err) {
>> ibdev_dbg(
>> &dev->ibdev,
>> "Couldn't mmap address[%#llx] length[%#zx] mmap_flag[%d] err[%d]\n",
>> entry->address, rdma_entry->npages * PAGE_SIZE,
>> entry->mmap_flag, err);
>> + atomic64_inc(&dev->stats.sw_stats.mmap_err);
>
> Really? Isn't this something that is only possible with a buggy
> rdma-core provider? Why count it?
Though unlikely, it could happen, otherwise this error flow wouldn't exist in
the first place.
If for some reason a customer app steps on a bug we're not aware of, this
counter could serve as a red flag.
