Re: [PATCH 22/27] IB/hfi1: Add receive fault injection feature

[Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

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On Sun, 2017-02-12 at 19:42 +0200, Leon Romanovsky wrote:
> On Wed, Feb 08, 2017 at 05:28:01AM -0800, Dennis Dalessandro wrote:
> > 
> > From: Mike Marciniszyn <mike.marciniszyn-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > 
> > Add fault injection capability:
> >   - Drop packets unconditionally (fault_by_packet)
> >   - Drop packets based on opcode (fault_by_opcode)
> > 
> > This feature is disabled by default and can be
> > enabled using the HFI1_FAULT_INJECTION Kconfig.
> > 
> > The faulting traces have been added:
> >   - misc/fault_opcode
> >   - misc/fault_packet
> > 
> > See 'Documentation/fault-injection/fault-injection.txt'
> > for details.
> > 
> > Examples:
> >   - Dropping packets by opcode:
> >     /sys/kernel/debug/hfi1/hfi1_X/fault_opcode
> > 	# Enable fault
> > 	echo Y > fault_by_opcode
> > 	# Setprobability of dropping (0-100%)
> > 	# echo 25 > probability
> > 	# Set opcode
> > 	echo 0x64 > opcode
> > 	# Number of times to fault
> > 	echo 3 > times
> > 	# An optional mask allows you to fault
> > 	# a range of opcodes
> > 	echo 0xf0 > mask
> >     /sys/kernel/debug/hfi1/hfi1_X/fault_stats
> >     contains a value in parentheses to indicate
> >     number of each opcode dropped.
> > 
> >   - Dropping packets unconditionally
> >     /sys/kernel/debug/hfi1/hfi1_X/fault_packet
> > 	# Enable fault
> > 	echo Y > fault_by_packet
> >     /sys/kernel/debug/hfi1/hfi1_X/fault_packet/fault_stats
> >     contains the number of packets dropped.
> > 
> > Signed-off-by: Mike Marciniszyn <mike.marciniszyn-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > Signed-off-by: Don Hiatt <don.hiatt-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > Signed-off-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > ---
> >  drivers/infiniband/hw/hfi1/Kconfig      |    6 +
> >  drivers/infiniband/hw/hfi1/debugfs.c    |  222
> > +++++++++++++++++++++++++++++++
> >  drivers/infiniband/hw/hfi1/debugfs.h    |   35 +++++
> >  drivers/infiniband/hw/hfi1/driver.c     |    8 +
> >  drivers/infiniband/hw/hfi1/trace_misc.h |   48 +++++++
> >  drivers/infiniband/hw/hfi1/verbs.c      |    6 +
> >  drivers/infiniband/hw/hfi1/verbs.h      |    4 +
> >  7 files changed, 329 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/infiniband/hw/hfi1/Kconfig
> > b/drivers/infiniband/hw/hfi1/Kconfig
> > index f6ea088..7465595 100644
> > --- a/drivers/infiniband/hw/hfi1/Kconfig
> > +++ b/drivers/infiniband/hw/hfi1/Kconfig
> > @@ -27,3 +27,9 @@ config SDMA_VERBOSITY
> >  	---help---
> >  	This is a configuration flag to enable verbose
> >  	SDMA debug
> > +config HFI1_FAULT_INJECTION
> > +	bool "Fault-injection capability"
> > +	depends on FAULT_INJECTION && FAULT_INJECTION_DEBUG_FS
> > +	default n
> 
> First no need to set default to "n", it is already default.
> Second, we got NAK from Doug while we proposed to add new Kconfig to
> our
> driver (mlx5) to improve debug.
> 
> Doug,
> I would like to know if your statement do not add new Kconfigs to IB
> is
> still relevant.

As much as is possible, yes.  Kconfig bloat is something I very much
want to avoid.  I would be more willing to have a single, global
CONFIG_INFINIBAND_DEBUG option that turned on debugging stack wide than
I would for individual drivers to each have their own debug configs.

-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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