From: Branden Bonaby <brandonbonaby94@gmail.com>
To: Michael Kelley <mikelley@microsoft.com>
Cc: KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
"sashal@kernel.org" <sashal@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/3] drivers: hv: vmbus: Introduce latency testing
Date: Fri, 23 Aug 2019 13:36:33 -0400 [thread overview]
Message-ID: <20190823173633.GA43233@Test-Virtual-Machine> (raw)
In-Reply-To: <DM5PR21MB01379300AF2B441D0B53692DD7A40@DM5PR21MB0137.namprd21.prod.outlook.com>
On Fri, Aug 23, 2019 at 04:44:09PM +0000, Michael Kelley wrote:
> From: Branden Bonaby <brandonbonaby94@gmail.com> Sent: Thursday, August 22, 2019 8:39 PM
> > > > diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> > > > index 09829e15d4a0..c9c63a4033cd 100644
> > > > --- a/drivers/hv/connection.c
> > > > +++ b/drivers/hv/connection.c
> > > > @@ -357,6 +357,9 @@ void vmbus_on_event(unsigned long data)
> > > >
> > > > trace_vmbus_on_event(channel);
> > > >
> > > > +#ifdef CONFIG_HYPERV_TESTING
> > > > + hv_debug_delay_test(channel, INTERRUPT_DELAY);
> > > > +#endif /* CONFIG_HYPERV_TESTING */
> > >
> > > You are following Vitaly's suggestion to use #ifdef's so no code is
> > > generated when HYPERV_TESTING is not enabled. However, this
> > > direct approach to using #ifdef's really clutters the code and makes
> > > it harder to read and follow. The better approach is to use the
> > > #ifdef in the include file where the functions are defined. If
> > > HYPERV_TESTING is not enabled, provide a #else that defines
> > > the function with an empty implementation for which the compiler
> > > will generate no code. An as example, see the function definition
> > > for hyperv_init() in arch/x86/include/asm/mshyperv.h. There are
> > > several functions treated similarly in that include file.
> > >
> >
> > I checked out the code in arch/x86/include/asm/mshyperv.h, after
> > thinking about it, I'm wondering if it would be better just to have
> > two files one called hv_debugfs.c and the other hyperv_debugfs.h.
> > I could put the code definitions in hv_debugfs.c and at the top
> > include the hyperv_debugfs.h file which would house the declarations
> > of these functions under the ifdef. Then like you alluded too use
> > an #else statement that would have the null implementations of the
> > above functions. Then put an #include "hyperv_debugfs.h" in the
> > hyperv_vmbus.h file. I figured instead of putting the code directly
> > into the vmbus_drv.c file it might be best to put them in a seperate
> > file like hv_debugfs.c. This way when we start adding more tests we
> > don't bloat the vmbus_drv.c file unnecessarily. The hv_debugfs.c
> > file would have the #ifdef CONFIG_HYPERV_TESTING at the top so if
> > its not enabled those null implementations in "hyperv_debugfs.h"
> > woud kick in anywhere that included the hyperv_vmbus.h file which
> > is what we want.
> >
> > what do you think?
> >
>
> I'll preface my comments by saying that how code gets structured
> into files is always a bit of a judgment call. The goal is to group code
> into sensible chunks to make it easy to understand and to make it
> easy to modify and extend later. The latter is a prediction about the
> future, which may or may not be accurate. For the former, what's
> "easy to understand," is often in the eye of the beholder. So you may
> get different opinions from different reviewers.
>
> That said, I like the idea of a separate hv_debugfs.c file to contain
> the implementation of the various functions you have added to
> provide the fuzzing capability. I'm less convinced about the value
> of a separate hyperv_debugfs.h file. I think you have one big
> #ifdef CONFIG_HYPERV_TESTING followed by the declarations of
> the functions in hv_debugfs.c, followed by #else and null
> implementations of those functions. This is 20 lines of code or so,
> and could easily go in hyperv_vmbus.h.
>
> For the new hv_debugfs.c, you can avoid the need for
> #ifdef CONFIG_HYPERV_TESTING by modifying the Makefile in
> drivers/hv so that hv_debugfs.o is built only if CONFIG_HYPERV_TESTING
> is defined. Look at the current Makefile to see how this is done
> with CONFIG_HYPERV_UTILS and CONFIG_HYPERV_BALLOON.
>
> Michael
>
I see, that does make sense, I'll go ahead and add these changes.
thanks
branden bonaby
next prev parent reply other threads:[~2019-08-23 17:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 2:44 [PATCH v2 0/3] hv: vmbus: add fuzz testing to hv device Branden Bonaby
2019-08-20 2:44 ` [PATCH v2 1/3] drivers: hv: vmbus: Introduce latency testing Branden Bonaby
2019-08-21 22:52 ` Michael Kelley
2019-08-23 3:38 ` Branden Bonaby
2019-08-23 16:44 ` Michael Kelley
2019-08-23 17:36 ` Branden Bonaby [this message]
2019-08-20 2:44 ` [PATCH v2 2/3] drivers: hv: vmbus: add test attributes to debugfs Branden Bonaby
2019-08-20 18:17 ` Branden Bonaby
2019-08-20 2:45 ` [PATCH v2 3/3] tools: hv: add vmbus testing tool Branden Bonaby
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190823173633.GA43233@Test-Virtual-Machine \
--to=brandonbonaby94@gmail.com \
--cc=haiyangz@microsoft.com \
--cc=kys@microsoft.com \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mikelley@microsoft.com \
--cc=sashal@kernel.org \
--cc=sthemmin@microsoft.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).