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From: Riccardo Mancini <rickyman7@gmail.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
	Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>, Jiri Olsa <jolsa@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-perf-users <linux-perf-users@vger.kernel.org>,
	Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Subject: Re: [RFC PATCH v2 01/10] perf workqueue: threadpool creation and destruction
Date: Wed, 11 Aug 2021 19:55:27 +0200	[thread overview]
Message-ID: <4941e4a6d898a4545ff319b6b74442e18ca8025a.camel@gmail.com> (raw)
In-Reply-To: <YRLgYDKRUfwLSyHF@kernel.org>

On Tue, 2021-08-10 at 17:24 -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Aug 10, 2021 at 11:54:19AM -0700, Namhyung Kim escreveu:
> > On Mon, Aug 9, 2021 at 3:30 AM Riccardo Mancini <rickyman7@gmail.com> wrote:
> > > On Fri, 2021-08-06 at 19:24 -0700, Namhyung Kim wrote:
> > > > > +/**
> > > > > + * threadpool__strerror - print message regarding given @err in @pool
> > > > > + *
> > > > > + * Buffer size should be at least THREADPOOL_STRERR_BUFSIZE bytes.
> > > > > + */
> > > > > +int threadpool__strerror(struct threadpool *pool __maybe_unused, int
> > > > > err,
> > > > > char *buf, size_t size)
> > > > > +{
> > > > > +       char sbuf[STRERR_BUFSIZE], *emsg;
> > > > > +
> > > > > +       emsg = str_error_r(err, sbuf, sizeof(sbuf));
> > > > > +       return scnprintf(buf, size, "Error: %s.\n", emsg);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * threadpool__new_strerror - print message regarding @err_ptr
> > > > > + *
> > > > > + * Buffer size should be at least THREADPOOL_STRERR_BUFSIZE bytes.
> > > > > + */
> > > > > +int threadpool__new_strerror(struct threadpool *err_ptr, char *buf,
> > > > > size_t
> > > > > size)
> > > > > +{
> > > > > +       return threadpool__strerror(err_ptr, PTR_ERR(err_ptr), buf,
> > > > > size);
> > > > > +}
> 
> > > > Why two different functions?
> 
> > > Since when new fails you don't have a err number, just an err_ptr so it's
> > > not
> > > very clear how to call threadpool__strerror. Therefore I made a wrapper to
> > > remove any ambiguity.
> > 
> > What do you mean by "when new fails"?
> 
> I think 'new' is 'constructor', i.e. something__new() returns a newly
> created object and this not an error number, so he uses ERR_PTR() and
> then he needs to pass it to the 'strerror' specific to the
> threadpool__new, which will use PTR_ERR() to get an integer, and then
> map that to a proper error string, right?

Correct. 
threadpool__new_strerror is not really needed since one could use
threadpool__strerror directly, but then I would need to handle all possible ways
it could be called (e.g. (NULL, PTR_ERR(err_ptr)), (err_ptr, 0), (err_ptr,
PTR_ERR(err_ptr)), so I thought it was better to just provide a strerror that
only took the err_ptr.
Maybe I can provide it as an inline in the header, or as a macro.

Riccardo

> 
> - Arnaldo



  reply	other threads:[~2021-08-11 17:55 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1627657061.git.rickyman7@gmail.com>
2021-07-30 15:34 ` Riccardo Mancini
2021-08-07  2:24   ` Namhyung Kim
2021-08-09 10:30     ` Riccardo Mancini
2021-08-10 18:54       ` Namhyung Kim
2021-08-10 20:24         ` Arnaldo Carvalho de Melo
2021-08-11 17:55           ` Riccardo Mancini [this message]
2021-07-30 15:34 ` [RFC PATCH v2 02/10] perf tests: add test for workqueue Riccardo Mancini
2021-07-30 15:34 ` [RFC PATCH v2 03/10] perf workqueue: add threadpool start and stop functions Riccardo Mancini
2021-08-07  2:43   ` Namhyung Kim
2021-08-09 10:35     ` Riccardo Mancini
2021-07-30 15:34 ` [RFC PATCH v2 04/10] perf workqueue: add threadpool execute and wait functions Riccardo Mancini
2021-08-07  2:56   ` Namhyung Kim
2021-07-30 15:34 ` [RFC PATCH v2 05/10] tools: add sparse context/locking annotations in compiler-types.h Riccardo Mancini
2021-07-30 15:34 ` [RFC PATCH v2 06/10] perf workqueue: introduce workqueue struct Riccardo Mancini
2021-08-09 12:04   ` Jiri Olsa
2021-07-30 15:34 ` [RFC PATCH v2 07/10] perf workqueue: implement worker thread and management Riccardo Mancini
2021-07-30 15:34 ` [RFC PATCH v2 08/10] perf workqueue: add queue_work and flush_workqueue functions Riccardo Mancini
2021-07-30 15:34 ` [RFC PATCH v2 09/10] perf workqueue: add utility to execute a for loop in parallel Riccardo Mancini
2021-07-30 15:34 ` [RFC PATCH v2 10/10] perf synthetic-events: use workqueue parallel_for Riccardo Mancini
2021-08-09 12:04   ` Jiri Olsa
2021-08-09 13:24     ` Riccardo Mancini

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