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>

1 files changed, 71 insertions, 0 deletions

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;
+}