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From: Leo Yan <leo.yan@linaro.org>
To: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 07/11] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head()
Date: Tue, 13 Jul 2021 21:10:18 +0800	[thread overview]
Message-ID: <20210713131018.GB748506@leoy-ThinkPad-X240s> (raw)
In-Reply-To: <4c65b6ba-2258-ff36-2ecc-92219e61e578@intel.com>

On Mon, Jul 12, 2021 at 05:32:11PM +0300, Adrian Hunter wrote:

[...]

> > --- a/tools/perf/util/auxtrace.c
> > +++ b/tools/perf/util/auxtrace.c
> > @@ -1686,13 +1686,12 @@ static int __auxtrace_mmap__read(struct mmap *map,
> >  	union perf_event ev;
> >  	void *data1, *data2;
> >  
> > +	head = auxtrace_mmap__read_head(mm);
> > +
> >  	if (snapshot) {
> > -		head = auxtrace_mmap__read_snapshot_head(mm);
> >  		if (auxtrace_record__find_snapshot(itr, mm->idx, mm, data,
> >  						   &head, &old))
> 
> That leaves a nested 'if' which is not kernel style i.e. could be
> 
> 	if (snapshot &&
> 	    auxtrace_record__find_snapshot(itr, mm->idx, mm, data, &head, &old))

Will refine in next spin, thanks for suggestion!

> >  			return -1;
> > -	} else {
> > -		head = auxtrace_mmap__read_head(mm);
> >  	}
> >  
> >  	if (old == head)

  reply	other threads:[~2021-07-13 13:10 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-11 10:40 [PATCH v4 00/11] perf: Refine barriers for AUX ring buffer Leo Yan
2021-07-11 10:40 ` [PATCH v4 01/11] perf/ring_buffer: Add comment for barriers on " Leo Yan
2021-07-11 10:40 ` [PATCH v4 02/11] coresight: tmc-etr: Add barrier after updating " Leo Yan
2021-07-12 10:40   ` Suzuki K Poulose
2021-07-12 10:54     ` Leo Yan
2021-07-11 10:40 ` [PATCH v4 03/11] coresight: tmc-etf: Add comment for store ordering Leo Yan
2021-07-13 12:56   ` Peter Zijlstra
2021-07-13 15:49     ` Leo Yan
2021-07-11 10:40 ` [PATCH v4 04/11] perf/x86: Add barrier after updating bts Leo Yan
2021-07-13 13:01   ` Peter Zijlstra
2021-07-11 10:40 ` [PATCH v4 05/11] perf auxtrace: Use WRITE_ONCE() for updating aux_tail Leo Yan
2021-07-11 10:41 ` [PATCH v4 06/11] perf auxtrace: Drop legacy __sync functions Leo Yan
2021-07-11 10:41 ` [PATCH v4 07/11] perf auxtrace: Remove auxtrace_mmap__read_snapshot_head() Leo Yan
2021-07-12 14:32   ` Adrian Hunter
2021-07-13 13:10     ` Leo Yan [this message]
2021-07-11 10:41 ` [PATCH v4 08/11] perf: Cleanup for HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT Leo Yan
2021-07-11 10:41 ` [PATCH v4 09/11] tools: Remove feature-sync-compare-and-swap feature detection Leo Yan
2021-07-11 10:41 ` [PATCH v4 10/11] perf env: Set flag for kernel is 64-bit mode Leo Yan
2021-07-12 14:37   ` Adrian Hunter
2021-07-12 18:14   ` Arnaldo Carvalho de Melo
2021-07-13 15:09     ` Leo Yan
2021-07-13 17:31       ` Hunter, Adrian
2021-07-14 13:59         ` Arnaldo Carvalho de Melo
2021-07-14 14:00           ` Arnaldo Carvalho de Melo
2021-07-23  7:11             ` Leo Yan
2021-07-11 10:41 ` [PATCH v4 11/11] perf auxtrace: Add compat_auxtrace_mmap__{read_head|write_tail} Leo Yan
2021-07-12 14:44   ` Russell King (Oracle)
2021-07-13 15:46     ` Leo Yan
2021-07-13 16:14       ` Russell King (Oracle)
2021-07-13 18:13         ` Catalin Marinas
2021-07-14  8:40           ` Russell King (Oracle)
2021-07-23  7:23             ` Leo Yan
2021-07-13  7:07   ` Adrian Hunter
2021-07-13 15:48     ` Leo Yan

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