On Sun, Apr 26, 2020 at 09:42:27AM +0300, Gal Pressman wrote:
> On 24/04/2020 21:26, Jason Gunthorpe wrote:
> > 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?
>
> It's not one against all others, most if not all of our userspace facing API
> error flows have a similar counter.
Hurm, seems a bit strange, but OK
> And TBH, I think that the mmap flow is quite convoluted with the cookie response
> from the crate verb, so it deserves a counter IMO.
How so? Userspace takes the u64 from the command and pass it to mmap,
what is convoluted?
Jason
