linux-kernel - Re: [PATCH 02/12] perf tools: Separate generic code in dso_cache_

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Message-ID: <20190416171712.GB8631@mini-arch.hsd1.ca.comcast.net>
Date:   Tue, 16 Apr 2019 10:17:13 -0700
From:   Stanislav Fomichev <sdf@...ichev.me>
To:     Jiri Olsa <jolsa@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Song Liu <songliubraving@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: Re: [PATCH 02/12] perf tools: Separate generic code in
 dso_cache__read

On 04/16, Jiri Olsa wrote:
> Moving file specific code in dso_cache__read function
> into separate file_read function. I'll add bpf specific
> code in following patches.
> 
> Link: http://lkml.kernel.org/n/tip-7f7d717uzrqt5ka2xp29ige3@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/perf/util/dso.c | 47 ++++++++++++++++++++++++-------------------
>  1 file changed, 26 insertions(+), 21 deletions(-)
> 
> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> index cb6199c1390a..6baad22ec8a9 100644
> --- a/tools/perf/util/dso.c
> +++ b/tools/perf/util/dso.c
> @@ -794,6 +794,30 @@ dso_cache__memcpy(struct dso_cache *cache, u64 offset,
>  	return cache_size;
>  }
>  
> +static ssize_t file_read(struct dso *dso, struct machine *machine,
> +			 u64 offset, char *data)
> +{
> +	ssize_t ret;
> +
> +	pthread_mutex_lock(&dso__data_open_lock);
> +
> +	/*
> +	 * dso->data.fd might be closed if other thread opened another
> +	 * file (dso) due to open file limit (RLIMIT_NOFILE).
> +	 */
> +	try_to_open_dso(dso, machine);
> +
> +	if (dso->data.fd < 0) {
> +		dso->data.status = DSO_DATA_STATUS_ERROR;
pthread_mutex_unlock(&dso__data_open_lock) here?

> +		return -errno;
> +	}
> +
> +	ret = pread(dso->data.fd, data, DSO__DATA_CACHE_SIZE, offset);
> +	pthread_mutex_unlock(&dso__data_open_lock);
> +
> +	return ret;
> +}
> +
>  static ssize_t
>  dso_cache__read(struct dso *dso, struct machine *machine,
>  		u64 offset, u8 *data, ssize_t size)
> @@ -803,37 +827,18 @@ dso_cache__read(struct dso *dso, struct machine *machine,
>  	ssize_t ret;
>  
>  	do {
> -		u64 cache_offset;
> +		u64 cache_offset = offset & DSO__DATA_CACHE_MASK;
>  
>  		cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);
>  		if (!cache)
>  			return -ENOMEM;
>  
> -		pthread_mutex_lock(&dso__data_open_lock);
> -
> -		/*
> -		 * dso->data.fd might be closed if other thread opened another
> -		 * file (dso) due to open file limit (RLIMIT_NOFILE).
> -		 */
> -		try_to_open_dso(dso, machine);
> -
> -		if (dso->data.fd < 0) {
> -			ret = -errno;
> -			dso->data.status = DSO_DATA_STATUS_ERROR;
> -			break;
> -		}
> -
> -		cache_offset = offset & DSO__DATA_CACHE_MASK;
> -
> -		ret = pread(dso->data.fd, cache->data, DSO__DATA_CACHE_SIZE, cache_offset);
> -		if (ret <= 0)
> -			break;
> +		ret = file_read(dso, machine, cache_offset, cache->data);
>  
>  		cache->offset = cache_offset;
>  		cache->size   = ret;
>  	} while (0);
>  
> -	pthread_mutex_unlock(&dso__data_open_lock);
>  
>  	if (ret > 0) {
>  		old = dso_cache__insert(dso, cache);
> -- 
> 2.17.2
>