On Fri, Apr 24, 2020 at 06:25:54PM +0300, Gal Pressman wrote:
> 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.
But there are lots of cases where a buggy provider can cause error
exits, why choose this one to count against all the others?
Jason
