[1/1] doc: expand description of no-huge and PMD issue
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Commit Message
Add more details to the description of a known issue of PMDs not being
usable when --no-huge EAL command line parameter is used. The issue
actually happens whenever there is a need for physical addresses, even
when there is no PMD attached.
Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
---
doc/guides/rel_notes/known_issues.rst | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
Comments
On Thu, Jun 9, 2022 at 3:40 PM Stanislaw Kardach <kda@semihalf.com> wrote:
>
> Add more details to the description of a known issue of PMDs not being
> usable when --no-huge EAL command line parameter is used. The issue
> actually happens whenever there is a need for physical addresses, even
> when there is no PMD attached.
>
> Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
Anatoly, Dmitry, opinions?
Thanks.
13/06/2022 11:31, David Marchand:
> On Thu, Jun 9, 2022 at 3:40 PM Stanislaw Kardach <kda@semihalf.com> wrote:
> >
> > Add more details to the description of a known issue of PMDs not being
> > usable when --no-huge EAL command line parameter is used. The issue
> > actually happens whenever there is a need for physical addresses, even
> > when there is no PMD attached.
> >
> > Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
>
> Anatoly, Dmitry, opinions?
> Thanks.
Why nobody is reviewing doc?
Ping for review
11/07/2022 23:09, Thomas Monjalon:
> 13/06/2022 11:31, David Marchand:
> > On Thu, Jun 9, 2022 at 3:40 PM Stanislaw Kardach <kda@semihalf.com> wrote:
> > >
> > > Add more details to the description of a known issue of PMDs not being
> > > usable when --no-huge EAL command line parameter is used. The issue
> > > actually happens whenever there is a need for physical addresses, even
> > > when there is no PMD attached.
> > >
> > > Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
> >
> > Anatoly, Dmitry, opinions?
> > Thanks.
>
> Why nobody is reviewing doc?
15/11/2022 16:37, Thomas Monjalon:
> Ping for review
>
> 11/07/2022 23:09, Thomas Monjalon:
> > 13/06/2022 11:31, David Marchand:
> > > On Thu, Jun 9, 2022 at 3:40 PM Stanislaw Kardach <kda@semihalf.com> wrote:
> > > >
> > > > Add more details to the description of a known issue of PMDs not being
> > > > usable when --no-huge EAL command line parameter is used. The issue
> > > > actually happens whenever there is a need for physical addresses, even
> > > > when there is no PMD attached.
> > > >
> > > > Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
> > >
> > > Anatoly, Dmitry, opinions?
> > > Thanks.
> >
> > Why nobody is reviewing doc?
Applied without review.
@@ -249,11 +249,15 @@ PMD does not work with --no-huge EAL command line parameter
-----------------------------------------------------------
**Description**:
- Currently, the DPDK does not store any information about memory allocated by ``malloc()` (for example, NUMA node,
- physical address), hence PMDs do not work when the ``--no-huge`` command line parameter is supplied to EAL.
+ Currently, the DPDK does not store any information about memory allocated by ``malloc()`` (for example, NUMA node,
+ physical address), hence PMDs do not work when the ``--no-huge`` command line parameter is supplied to EAL. This
+ happens when using non-IOMMU based UIO drivers (i.e. ``igb_uio`` or ``uio_pci_generic``) or when IOVA mode is
+ explicitly set to use physical addresses (via the ``--iova-mode=pa`` EAL parameter).
**Implication**:
- Sending and receiving data with PMD will not work.
+ Sending and receiving data with PMD will not work. Unit tests checking ``--no-huge`` operation will fail if
+ there is a device bound to the PMD (eal_flags_n_opt_autotest, eal_flags_no_huge_autotest,
+ eal_flags_vdev_opt_autotest, eal_flags_misc_autotest).
**Resolution/Workaround**:
Use huge page memory or use VFIO to map devices.