From: brendanhiggins@google.com (Brendan Higgins)
Subject: [RFC v3 03/19] kunit: test: add string_stream a std::stream like string builder
Date: Mon, 3 Dec 2018 16:35:12 -0800 [thread overview]
Message-ID: <CAFd5g47pWbPso4LG93ffRUZjLhxnqws5VfYc5SfFf8FbuYCWvA@mail.gmail.com> (raw)
Message-ID: <20181204003512.UEuVaECdtBJ0y-oDhmTe7HjtyK4ZRUvU2r2Ya4eVl3I@z> (raw)
In-Reply-To: <20181203105517.vbedwygttxxbdtan@pathway.suse.cz>
On Mon, Dec 3, 2018@2:55 AM Petr Mladek <pmladek@suse.com> wrote:
>
> On Thu 2018-11-29 19:29:24, Luis Chamberlain wrote:
> > On Wed, Nov 28, 2018@11:36:20AM -0800, Brendan Higgins wrote:
> > > A number of test features need to do pretty complicated string printing
> > > where it may not be possible to rely on a single preallocated string
> > > with parameters.
> > >
> > > So provide a library for constructing the string as you go similar to
> > > C++'s std::string.
> >
> > Hrm, what's the potential for such thing actually being eventually
> > generically useful for printk folks, I wonder? Petr?
>
> printk() is a bit tricky:
>
> + It should work in any context. Any additional lock adds risk of a
> deadlock. Especially the NMI and scheduler contexts are problematic.
> There are problems with any other code that might be called
> from console drivers and calls printk() under a lock.
>
> + It should work also when the system is out of memory. Especially
> atomic context is problematic because we could not wait for
> memory reclaim or swap.
>
> + We also do to the best effort to get the message out on the
> console. It is important when the system is about to die.
> Any extra buffering layer might cause delay and avoid seeing the
> message.
>
> From this point of views, this API is not generally usable with printk().
Yeah, that makes sense. I wouldn't really expect this to work well in
those cases.
> Now, the question is how many of the above fits also for unit testing.
> At least, you might need to be careful when allocating memory in
> atomic context.
True, but this is only supposed to be used for constructing
expectation failure messages which should only happen from a
non-atomic context.
>
> BTW: There are more existing printk APIs: Well, I admit the they are
> not easily reusable in unit testing:
>
> + printk() is old, crappy code, complicated with all the
> cornercases and consoles.
>
> + include/linux/seq_buf.h is simple buffering. It is used primary
> for sysfs output. It might be usable if you add support for
> loglevel and use big enough buffer. I quess that you should
> flush the buffer regularly anyway.
>
> + trace_printk() uses lockless per-CPU buffers. It currently does not
> support loglevels. But it might be pretty interesting choice as well.
>
>
> I do not say that you have to use one of the existing API. But you
> might consider them if you encouter any problems and maintaining
> your variant gets complicated.
Alright, I will take a look.
Thanks!
next prev parent reply other threads:[~2018-12-04 0:35 UTC|newest]
Thread overview: 232+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 19:36 [RFC v3 00/19] kunit: introduce KUnit, the Linux kernel unit testing framework brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 01/19] kunit: test: add KUnit test runner core brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-30 3:14 ` mcgrof
2018-11-30 3:14 ` Luis Chamberlain
2018-12-01 1:51 ` brendanhiggins
2018-12-01 1:51 ` Brendan Higgins
2018-12-01 2:57 ` mcgrof
2018-12-01 2:57 ` Luis Chamberlain
2018-12-05 13:15 ` anton.ivanov
2018-12-05 13:15 ` Anton Ivanov
2018-12-05 14:45 ` arnd
2018-12-05 14:45 ` Arnd Bergmann
2018-12-05 14:49 ` anton.ivanov
2018-12-05 14:49 ` Anton Ivanov
2018-11-30 3:28 ` mcgrof
2018-11-30 3:28 ` Luis Chamberlain
2018-12-01 2:08 ` brendanhiggins
2018-12-01 2:08 ` Brendan Higgins
2018-12-01 3:10 ` mcgrof
2018-12-01 3:10 ` Luis Chamberlain
2018-12-03 22:47 ` brendanhiggins
2018-12-03 22:47 ` Brendan Higgins
2018-12-01 3:02 ` mcgrof
2018-12-01 3:02 ` Luis Chamberlain
2018-11-28 19:36 ` [RFC v3 02/19] kunit: test: add test resource management API brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 03/19] kunit: test: add string_stream a std::stream like string builder brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-30 3:29 ` mcgrof
2018-11-30 3:29 ` Luis Chamberlain
2018-12-01 2:14 ` brendanhiggins
2018-12-01 2:14 ` Brendan Higgins
2018-12-01 3:12 ` mcgrof
2018-12-01 3:12 ` Luis Chamberlain
2018-12-03 10:55 ` pmladek
2018-12-03 10:55 ` Petr Mladek
2018-12-04 0:35 ` brendanhiggins [this message]
2018-12-04 0:35 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 04/19] kunit: test: add test_stream a std::stream like logger brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 05/19] kunit: test: add the concept of expectations brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 06/19] arch: um: enable running kunit from User Mode Linux brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 21:26 ` robh
2018-11-28 21:26 ` Rob Herring
2018-11-30 3:37 ` mcgrof
2018-11-30 3:37 ` Luis Chamberlain
2018-11-30 14:05 ` robh
2018-11-30 14:05 ` Rob Herring
2018-11-30 18:22 ` mcgrof
2018-11-30 18:22 ` Luis Chamberlain
2018-12-03 23:22 ` brendanhiggins
2018-12-03 23:22 ` Brendan Higgins
2018-11-30 3:30 ` mcgrof
2018-11-30 3:30 ` Luis Chamberlain
2018-11-28 19:36 ` [RFC v3 07/19] kunit: test: add initial tests brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-30 3:40 ` mcgrof
2018-11-30 3:40 ` Luis Chamberlain
2018-12-03 23:26 ` brendanhiggins
2018-12-03 23:26 ` Brendan Higgins
2018-12-03 23:43 ` mcgrof
2018-12-03 23:43 ` Luis Chamberlain
2018-11-28 19:36 ` [RFC v3 08/19] arch: um: add shim to trap to allow installing a fault catcher for tests brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-30 3:34 ` mcgrof
2018-11-30 3:34 ` Luis Chamberlain
2018-12-03 23:34 ` brendanhiggins
2018-12-03 23:34 ` Brendan Higgins
2018-12-03 23:46 ` mcgrof
2018-12-03 23:46 ` Luis Chamberlain
2018-12-04 0:44 ` brendanhiggins
2018-12-04 0:44 ` Brendan Higgins
2018-11-30 3:41 ` mcgrof
2018-11-30 3:41 ` Luis Chamberlain
2018-12-03 23:37 ` brendanhiggins
2018-12-03 23:37 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 09/19] kunit: test: add the concept of assertions brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 10/19] kunit: test: add test managed resource tests brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 11/19] kunit: add Python libraries for handing KUnit config and kernel brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-29 13:54 ` kieran.bingham
2018-11-29 13:54 ` Kieran Bingham
2018-12-03 23:48 ` brendanhiggins
2018-12-03 23:48 ` Brendan Higgins
2018-12-04 20:47 ` mcgrof
2018-12-04 20:47 ` Luis Chamberlain
2018-12-06 12:32 ` kieran.bingham
2018-12-06 12:32 ` Kieran Bingham
2018-12-06 15:37 ` willy
2018-12-06 15:37 ` Matthew Wilcox
2018-12-07 11:30 ` kieran.bingham
2018-12-07 11:30 ` Kieran Bingham
2018-12-11 14:09 ` pmladek
2018-12-11 14:09 ` Petr Mladek
2018-12-11 14:41 ` rostedt
2018-12-11 14:41 ` Steven Rostedt
2018-12-11 17:01 ` anton.ivanov
2018-12-11 17:01 ` Anton Ivanov
2019-02-09 0:40 ` brendanhiggins
2019-02-09 0:40 ` Brendan Higgins
2018-12-07 1:05 ` mcgrof
2018-12-07 1:05 ` Luis Chamberlain
2018-12-07 18:35 ` kent.overstreet
2018-12-07 18:35 ` Kent Overstreet
2018-11-30 3:44 ` mcgrof
2018-11-30 3:44 ` Luis Chamberlain
2018-12-03 23:50 ` brendanhiggins
2018-12-03 23:50 ` Brendan Higgins
2018-12-04 20:48 ` mcgrof
2018-12-04 20:48 ` Luis Chamberlain
2018-11-28 19:36 ` [RFC v3 12/19] kunit: add KUnit wrapper script and simple output parser brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 13/19] kunit: improve output from python wrapper brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 14/19] Documentation: kunit: add documentation for KUnit brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-29 13:56 ` kieran.bingham
2018-11-29 13:56 ` Kieran Bingham
2018-11-30 3:45 ` mcgrof
2018-11-30 3:45 ` Luis Chamberlain
2018-12-03 23:53 ` brendanhiggins
2018-12-03 23:53 ` Brendan Higgins
2018-12-06 12:16 ` kieran.bingham
2018-12-06 12:16 ` Kieran Bingham
2019-02-09 0:56 ` brendanhiggins
2019-02-09 0:56 ` Brendan Higgins
2019-02-11 12:16 ` kieran.bingham
2019-02-11 12:16 ` Kieran Bingham
2019-02-12 22:10 ` brendanhiggins
2019-02-12 22:10 ` Brendan Higgins
2019-02-13 21:55 ` kieran.bingham
2019-02-13 21:55 ` Kieran Bingham
2019-02-14 0:17 ` brendanhiggins
2019-02-14 0:17 ` Brendan Higgins
2019-02-14 17:26 ` mcgrof
2019-02-14 17:26 ` Luis Chamberlain
2019-02-14 22:07 ` brendanhiggins
2019-02-14 22:07 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 15/19] MAINTAINERS: add entry for KUnit the unit testing framework brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 16/19] arch: um: make UML unflatten device tree when testing brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-11-28 21:16 ` robh
2018-11-28 21:16 ` Rob Herring
2018-12-04 0:00 ` brendanhiggins
2018-12-04 0:00 ` Brendan Higgins
2018-11-30 3:46 ` mcgrof
2018-11-30 3:46 ` Luis Chamberlain
2018-12-04 0:02 ` brendanhiggins
2018-12-04 0:02 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 17/19] of: unittest: migrate tests to run on KUnit brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
[not found] ` <CAL_Jsq+09Kx7yMBC_Jw45QGmk6U_fp4N6HOZDwYrM4tWw+_dOA@mail.gmail.com>
2018-11-30 0:39 ` rdunlap
2018-11-30 0:39 ` Randy Dunlap
2018-12-04 0:13 ` brendanhiggins
2018-12-04 0:13 ` Brendan Higgins
2018-12-04 13:40 ` robh
2018-12-04 13:40 ` Rob Herring
2018-12-05 23:42 ` brendanhiggins
2018-12-05 23:42 ` Brendan Higgins
2018-12-07 0:41 ` robh
2018-12-07 0:41 ` Rob Herring
2018-12-04 0:08 ` brendanhiggins
2018-12-04 0:08 ` Brendan Higgins
2019-02-13 1:44 ` brendanhiggins
2019-02-13 1:44 ` Brendan Higgins
2019-02-14 20:10 ` robh
2019-02-14 20:10 ` Rob Herring
2019-02-14 21:52 ` brendanhiggins
2019-02-14 21:52 ` Brendan Higgins
2019-02-18 22:56 ` frowand.list
2019-02-18 22:56 ` Frank Rowand
2019-02-28 0:29 ` brendanhiggins
2019-02-28 0:29 ` Brendan Higgins
2018-12-04 10:56 ` frowand.list
2018-12-04 10:56 ` Frank Rowand
2018-11-28 19:36 ` [RFC v3 18/19] of: unittest: split out a couple of test cases from unittest brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-12-04 10:58 ` frowand.list
2018-12-04 10:58 ` Frank Rowand
2018-12-05 23:54 ` brendanhiggins
2018-12-05 23:54 ` Brendan Higgins
2019-02-14 23:57 ` frowand.list
2019-02-14 23:57 ` Frank Rowand
2019-02-15 0:56 ` brendanhiggins
2019-02-15 0:56 ` Brendan Higgins
2019-02-15 2:05 ` frowand.list
2019-02-15 2:05 ` Frank Rowand
2019-02-15 10:56 ` brendanhiggins
2019-02-15 10:56 ` Brendan Higgins
2019-02-18 22:25 ` frowand.list
2019-02-18 22:25 ` Frank Rowand
2019-02-20 20:44 ` frowand.list
2019-02-20 20:44 ` Frank Rowand
2019-02-20 20:47 ` frowand.list
2019-02-20 20:47 ` Frank Rowand
2019-02-28 3:52 ` brendanhiggins
2019-02-28 3:52 ` Brendan Higgins
2019-03-22 0:22 ` frowand.list
2019-03-22 0:22 ` Frank Rowand
2019-03-22 1:30 ` brendanhiggins
2019-03-22 1:30 ` Brendan Higgins
2019-03-22 1:47 ` frowand.list
2019-03-22 1:47 ` Frank Rowand
2019-03-25 22:15 ` brendanhiggins
2019-03-25 22:15 ` Brendan Higgins
2019-09-20 16:57 ` Rob Herring
2019-09-21 23:57 ` Frank Rowand
2019-03-22 1:34 ` frowand.list
2019-03-22 1:34 ` Frank Rowand
2019-03-25 22:18 ` brendanhiggins
2019-03-25 22:18 ` Brendan Higgins
2018-11-28 19:36 ` [RFC v3 19/19] of: unittest: split up some super large test cases brendanhiggins
2018-11-28 19:36 ` Brendan Higgins
2018-12-04 10:52 ` [RFC v3 00/19] kunit: introduce KUnit, the Linux kernel unit testing framework frowand.list
2018-12-04 10:52 ` Frank Rowand
2018-12-04 11:40 ` frowand.list
2018-12-04 11:40 ` Frank Rowand
2018-12-04 13:49 ` robh
2018-12-04 13:49 ` Rob Herring
2018-12-05 23:10 ` brendanhiggins
2018-12-05 23:10 ` Brendan Higgins
2019-03-22 0:27 ` frowand.list
2019-03-22 0:27 ` Frank Rowand
2019-03-25 22:04 ` brendanhiggins
2019-03-25 22:04 ` Brendan Higgins
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