perf session: Cleanup __perf_session__process_events()

Replace the pseudo C++ self argument with session and give the mmap related
variables a sensible name. shift is a complete misnomer - it took me several
rounds of cursing to figure out that it's not a shift value.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101130163820.029687218@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 37 insertions, 40 deletions

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 525bcf6adc21..2fdbccf10770 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -567,13 +567,13 @@ static int perf_session__process_sample(event_t *event, struct perf_session *s,
 static int perf_session__process_event(struct perf_session *self,
                                        event_t *event,
                                        struct perf_event_ops *ops,
-                                       u64 offset, u64 head)
+                                       u64 file_offset)
 {
         trace_event(event);
 
         if (event->header.type < PERF_RECORD_HEADER_MAX) {
                 dump_printf("%#Lx [%#x]: PERF_RECORD_%s",
-                            offset + head, event->header.size,
+                            file_offset, event->header.size,
                             event__name[event->header.type]);
                 hists__inc_nr_events(&self->hists, event->header.type);
         }
@@ -606,7 +606,7 @@ static int perf_session__process_event(struct perf_session *self,
                 return ops->event_type(event, self);
         case PERF_RECORD_HEADER_TRACING_DATA:
                 /* setup for reading amidst mmap */
-                lseek(self->fd, offset + head, SEEK_SET);
+                lseek(self->fd, file_offset, SEEK_SET);
                 return ops->tracing_data(event, self);
         case PERF_RECORD_HEADER_BUILD_ID:
                 return ops->build_id(event, self);
@@ -705,8 +705,7 @@ more:
         }
 
         if (size == 0 ||
-            (skip = perf_session__process_event(self, &event, ops,
-                                                0, head)) < 0) {
+            (skip = perf_session__process_event(self, &event, ops, head)) < 0) {
                 dump_printf("%#Lx [%#x]: skipping unknown header type: %d\n",
                             head, event.header.size, event.header.type);
                 /*
@@ -735,19 +734,19 @@ out_err:
         return err;
 }
 
-int __perf_session__process_events(struct perf_session *self,
+int __perf_session__process_events(struct perf_session *session,
                                    u64 data_offset, u64 data_size,
                                    u64 file_size, struct perf_event_ops *ops)
 {
+        u64 head, page_offset, file_offset;
         int err, mmap_prot, mmap_flags;
-        u64 head, shift;
-        u64 offset = 0;
+        struct ui_progress *progress;
         size_t  page_size;
         event_t *event;
         uint32_t size;
         char *buf;
-        struct ui_progress *progress = ui_progress__new("Processing events...",
-                                                        self->size);
+
+        progress = ui_progress__new("Processing events...", session->size);
         if (progress == NULL)
                 return -1;
 
@@ -755,21 +754,20 @@ int __perf_session__process_events(struct perf_session *self,
 
         page_size = sysconf(_SC_PAGESIZE);
 
-        head = data_offset;
-        shift = page_size * (head / page_size);
-        offset += shift;
-        head -= shift;
+        page_offset = page_size * (data_offset / page_size);
+        file_offset = page_offset;
+        head = data_offset - page_offset;
 
         mmap_prot  = PROT_READ;
         mmap_flags = MAP_SHARED;
 
-        if (self->header.needs_swap) {
+        if (session->header.needs_swap) {
                 mmap_prot  |= PROT_WRITE;
                 mmap_flags = MAP_PRIVATE;
         }
 remap:
-        buf = mmap(NULL, page_size * self->mmap_window, mmap_prot,
-                   mmap_flags, self->fd, offset);
+        buf = mmap(NULL, page_size * session->mmap_window, mmap_prot,
+                   mmap_flags, session->fd, file_offset);
         if (buf == MAP_FAILED) {
                 pr_err("failed to mmap file\n");
                 err = -errno;
@@ -778,36 +776,35 @@ remap:
 
 more:
         event = (event_t *)(buf + head);
-        ui_progress__update(progress, offset);
+        ui_progress__update(progress, file_offset);
 
-        if (self->header.needs_swap)
+        if (session->header.needs_swap)
                 perf_event_header__bswap(&event->header);
         size = event->header.size;
         if (size == 0)
                 size = 8;
 
-        if (head + event->header.size >= page_size * self->mmap_window) {
+        if (head + event->header.size >= page_size * session->mmap_window) {
                 int munmap_ret;
 
-                shift = page_size * (head / page_size);
-
-                munmap_ret = munmap(buf, page_size * self->mmap_window);
+                munmap_ret = munmap(buf, page_size * session->mmap_window);
                 assert(munmap_ret == 0);
 
-                offset += shift;
-                head -= shift;
+                page_offset = page_size * (head / page_size);
+                file_offset += page_offset;
+                head -= page_offset;
                 goto remap;
         }
 
         size = event->header.size;
 
         dump_printf("\n%#Lx [%#x]: event: %d\n",
-                    offset + head, event->header.size, event->header.type);
+                    file_offset + head, event->header.size, event->header.type);
 
-        if (size == 0 ||
-            perf_session__process_event(self, event, ops, offset, head) < 0) {
+        if (size == 0 || perf_session__process_event(session, event, ops,
+                                                     file_offset + head) < 0) {
                 dump_printf("%#Lx [%#x]: skipping unknown header type: %d\n",
-                            offset + head, event->header.size,
+                            file_offset + head, event->header.size,
                             event->header.type);
                 /*
                  * assume we lost track of the stream, check alignment, and
@@ -821,36 +818,36 @@ more:
 
         head += size;
 
-        if (offset + head >= data_offset + data_size)
+        if (file_offset + head >= data_offset + data_size)
                 goto done;
 
-        if (offset + head < file_size)
+        if (file_offset + head < file_size)
                 goto more;
 done:
         err = 0;
         /* do the final flush for ordered samples */
-        self->ordered_samples.next_flush = ULLONG_MAX;
-        flush_sample_queue(self, ops);
+        session->ordered_samples.next_flush = ULLONG_MAX;
+        flush_sample_queue(session, ops);
 out_err:
         ui_progress__delete(progress);
 
         if (ops->lost == event__process_lost &&
-            self->hists.stats.total_lost != 0) {
+            session->hists.stats.total_lost != 0) {
                 ui__warning("Processed %Lu events and LOST %Lu!\n\n"
                             "Check IO/CPU overload!\n\n",
-                            self->hists.stats.total_period,
-                            self->hists.stats.total_lost);
+                            session->hists.stats.total_period,
+                            session->hists.stats.total_lost);
         }
-        
-        if (self->hists.stats.nr_unknown_events != 0) {
+
+        if (session->hists.stats.nr_unknown_events != 0) {
                 ui__warning("Found %u unknown events!\n\n"
                             "Is this an older tool processing a perf.data "
                             "file generated by a more recent tool?\n\n"
                             "If that is not the case, consider "
                             "reporting to linux-kernel@vger.kernel.org.\n\n",
-                            self->hists.stats.nr_unknown_events);
+                            session->hists.stats.nr_unknown_events);
         }
-                
+
         return err;
 }