Commit b5911e7a authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
Browse files

libperf: Introduce perf_evlist_mmap_ops::mmap callback 



Add the perf_evlist_mmap_ops::mmap callback to be called in
mmap_per_evsel() to actually mmap the map.

Add libperf's perf_evlist__mmap_cb_mmap() function as libperf's mmap
callback.

New mmaped map gets refcount set to 2 in mmap__mmap(), we follow that in
mmap callback. We will move this to common place after we switch to
perf_evlist__mmap().

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20191007125344.14268-18-jolsa@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3a8bb581

tools/perf/lib/evlist.c

+26 −3
Original line number Diff line number Diff line
@@ -358,6 +358,28 @@ perf_evlist__mmap_cb_get(struct perf_evlist *evlist, bool overwrite, int idx) 


#define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))



static int

perf_evlist__mmap_cb_mmap(struct perf_mmap *map, struct perf_mmap_param *mp,

			  int output, int cpu)

{

	/*

	 * The last one will be done at perf_mmap__consume(), so that we

	 * make sure we don't prevent tools from consuming every last event in

	 * the ring buffer.

	 *

	 * I.e. we can get the POLLHUP meaning that the fd doesn't exist

	 * anymore, but the last events for it are still in the ring buffer,

	 * waiting to be consumed.

	 *

	 * Tools can chose to ignore this at their own discretion, but the

	 * evlist layer can't just drop it when filtering events in

	 * perf_evlist__filter_pollfd().

	 */

	refcount_set(&map->refcnt, 2);



	return perf_mmap__mmap(map, mp, output, cpu);

}



static int

mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,

	       int idx, struct perf_mmap_param *mp, int cpu_idx,
@@ -396,7 +418,7 @@ mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops, 
		if (*output == -1) {

			*output = fd;



			if (perf_mmap__mmap(map, mp, *output, evlist_cpu) < 0)

			if (ops->mmap(map, mp, *output, evlist_cpu) < 0)

				return -1;

		} else {

			if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
@@ -488,7 +510,7 @@ int perf_evlist__mmap_ops(struct perf_evlist *evlist, 
	const struct perf_cpu_map *cpus = evlist->cpus;

	const struct perf_thread_map *threads = evlist->threads;



	if (!ops || !ops->get)

	if (!ops || !ops->get || !ops->mmap)

		return -EINVAL;



	if (!evlist->mmap)
@@ -514,6 +536,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, int pages) 
	struct perf_mmap_param mp;

	struct perf_evlist_mmap_ops ops = {

		.get  = perf_evlist__mmap_cb_get,

		.mmap = perf_evlist__mmap_cb_mmap,

	};



	evlist->mmap_len = (pages + 1) * page_size;

tools/perf/lib/include/internal/evlist.h

+3 −0
Original line number Diff line number Diff line
@@ -31,10 +31,13 @@ typedef void 
(*perf_evlist_mmap__cb_idx_t)(struct perf_evlist*, struct perf_mmap_param*, int, bool);

typedef struct perf_mmap*

(*perf_evlist_mmap__cb_get_t)(struct perf_evlist*, bool, int);

typedef int

(*perf_evlist_mmap__cb_mmap_t)(struct perf_mmap*, struct perf_mmap_param*, int, int);



struct perf_evlist_mmap_ops {

	perf_evlist_mmap__cb_idx_t	idx;

	perf_evlist_mmap__cb_get_t	get;

	perf_evlist_mmap__cb_mmap_t	mmap;

};



int perf_evlist__alloc_pollfd(struct perf_evlist *evlist);

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