perf evsel: Introduce mmap support

Out of the code in 'perf top'. Record is next in line.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 88 insertions, 0 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 2abf949259d0..6d4129214ee8 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -60,3 +60,11 @@ int perf_evlist__alloc_pollfd(struct perf_evlist *evlist, int ncpus, int nthread
 	evlist->pollfd = malloc(sizeof(struct pollfd) * nfds);
 	return evlist->pollfd != NULL ? 0 : -ENOMEM;
 }
+
+void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
+{
+	fcntl(fd, F_SETFL, O_NONBLOCK);
+	evlist->pollfd[evlist->nr_fds].fd = fd;
+	evlist->pollfd[evlist->nr_fds].events = POLLIN;
+	evlist->nr_fds++;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index a7d7e122e3c6..16bbfcba8ca8 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -21,5 +21,6 @@ void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
 int perf_evlist__add_default(struct perf_evlist *evlist);
 
 int perf_evlist__alloc_pollfd(struct perf_evlist *evlist, int ncpus, int nthreads);
+void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd);
 
 #endif /* __PERF_EVLIST_H */
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 82a00536892a..f5006958f8da 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1,9 +1,13 @@
 #include "evsel.h"
+#include "evlist.h"
 #include "../perf.h"
 #include "util.h"
 #include "cpumap.h"
 #include "thread.h"
 
+#include <unistd.h>
+#include <sys/mman.h>
+
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
 
 struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr, int idx)
@@ -49,10 +53,32 @@ void perf_evsel__close_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
 		}
 }
 
+void perf_evsel__munmap(struct perf_evsel *evsel, int ncpus, int nthreads)
+{
+	struct perf_mmap *mm;
+	int cpu, thread;
+
+	for (cpu = 0; cpu < ncpus; cpu++)
+		for (thread = 0; thread < nthreads; ++thread) {
+			mm = xyarray__entry(evsel->mmap, cpu, thread);
+			if (mm->base != NULL) {
+				munmap(mm->base, evsel->mmap_len);
+				mm->base = NULL;
+			}
+		}
+}
+
+int perf_evsel__alloc_mmap(struct perf_evsel *evsel, int ncpus, int nthreads)
+{
+	evsel->mmap = xyarray__new(ncpus, nthreads, sizeof(struct perf_mmap));
+	return evsel->mmap != NULL ? 0 : -ENOMEM;
+}
+
 void perf_evsel__delete(struct perf_evsel *evsel)
 {
 	assert(list_empty(&evsel->node));
 	xyarray__delete(evsel->fd);
+	xyarray__delete(evsel->mmap);
 	free(evsel);
 }
 
@@ -208,3 +234,48 @@ int perf_evsel__open_per_thread(struct perf_evsel *evsel,
 {
 	return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group, inherit);
 }
+
+int perf_evsel__mmap(struct perf_evsel *evsel, struct cpu_map *cpus,
+		     struct thread_map *threads, int pages,
+		     struct perf_evlist *evlist)
+{
+	unsigned int page_size = sysconf(_SC_PAGE_SIZE);
+	int mask = pages * page_size - 1, cpu;
+	struct perf_mmap *mm;
+	int thread;
+
+	if (evsel->mmap == NULL &&
+	    perf_evsel__alloc_mmap(evsel, cpus->nr, threads->nr) < 0)
+		return -ENOMEM;
+
+	evsel->mmap_len = (pages + 1) * page_size;
+
+	for (cpu = 0; cpu < cpus->nr; cpu++) {
+		for (thread = 0; thread < threads->nr; thread++) {
+			mm = xyarray__entry(evsel->mmap, cpu, thread);
+			mm->prev = 0;
+			mm->mask = mask;
+			mm->base = mmap(NULL, evsel->mmap_len, PROT_READ,
+					MAP_SHARED, FD(evsel, cpu, thread), 0);
+			if (mm->base == MAP_FAILED)
+				goto out_unmap;
+
+			if (evlist != NULL)
+				 perf_evlist__add_pollfd(evlist, FD(evsel, cpu, thread));
+		}
+	}
+
+	return 0;
+
+out_unmap:
+	do {
+		while (--thread >= 0) {
+			mm = xyarray__entry(evsel->mmap, cpu, thread);
+			munmap(mm->base, evsel->mmap_len);
+			mm->base = NULL;
+		}
+		thread = threads->nr;
+	} while (--cpu >= 0);
+
+	return -1;
+}
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 1594696bd127..c8fbef299436 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -29,19 +29,23 @@ struct perf_evsel {
 	struct perf_event_attr	attr;
 	char			*filter;
 	struct xyarray		*fd;
+	struct xyarray		*mmap;
 	struct perf_counts	*counts;
+	size_t			mmap_len;
 	int			idx;
 	void			*priv;
 };
 
 struct cpu_map;
 struct thread_map;
+struct perf_evlist;
 
 struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr, int idx);
 void perf_evsel__delete(struct perf_evsel *evsel);
 
 int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
 int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus);
+int perf_evsel__alloc_mmap(struct perf_evsel *evsel, int ncpus, int nthreads);
 void perf_evsel__free_fd(struct perf_evsel *evsel);
 void perf_evsel__close_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
 
@@ -51,6 +55,10 @@ int perf_evsel__open_per_thread(struct perf_evsel *evsel,
 				struct thread_map *threads, bool group, bool inherit);
 int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 		     struct thread_map *threads, bool group, bool inherit);
+int perf_evsel__mmap(struct perf_evsel *evsel, struct cpu_map *cpus,
+		     struct thread_map *threads, int pages,
+		     struct perf_evlist *evlist);
+void perf_evsel__munmap(struct perf_evsel *evsel, int ncpus, int nthreads);
 
 #define perf_evsel__match(evsel, t, c)		\
 	(evsel->attr.type == PERF_TYPE_##t &&	\