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authorFrederic Weisbecker <fweisbec@gmail.com>2009-10-06 21:21:26 +0200
committerIngo Molnar <mingo@elte.hu>2009-10-07 08:36:10 +0200
commitb209aa1f83964d49a332a7b6b818ebede5cdc6ef (patch)
tree65899a686eedd374d0524a0812273bdeac5f08a3
parent42e59d7d19dc4b49feab2a860fd9a8ca3248c833 (diff)
perf tools: Start the perf.data mapping at data offset in perf trace
Currently, we are mapping perf.data in the beginning of the file and use the data offset as a buffer offset. This may exceed the mapping area if the data offset is upper than page_size * mmap_window and result in a page fault (thing that happen if we merge trace.info in perf.data). Instead, let's start the mapping in the page that matches our data offset. v2: Drop a junk from another patch (trace_report() removal) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <1254856886-10348-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--tools/perf/builtin-trace.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 5d4c84d8637..d573d4ea6c2 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -143,6 +143,7 @@ static int __cmd_trace(void)
int ret, rc = EXIT_FAILURE;
unsigned long offset = 0;
unsigned long head = 0;
+ unsigned long shift;
struct stat perf_stat;
event_t *event;
uint32_t size;
@@ -180,6 +181,10 @@ static int __cmd_trace(void)
return EXIT_FAILURE;
}
+ shift = page_size * (head / page_size);
+ offset += shift;
+ head -= shift;
+
remap:
buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
MAP_SHARED, input, offset);
@@ -192,9 +197,9 @@ more:
event = (event_t *)(buf + head);
if (head + event->header.size >= page_size * mmap_window) {
- unsigned long shift = page_size * (head / page_size);
int res;
+ shift = page_size * (head / page_size);
res = munmap(buf, page_size * mmap_window);
assert(res == 0);