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Commit b209aa1f authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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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: default avatarFrederic 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: default avatarIngo Molnar <mingo@elte.hu>
parent 42e59d7d

tools/perf/builtin-trace.c

+6 −1
Original line number Diff line number Diff line
@@ -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 @@ static int __cmd_trace(void) 
	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);