Commit-ID: 304703aba31a87903b8c0db8f5e6890cac2d596d Gitweb: http://git.kernel.org/tip/304703aba31a87903b8c0db8f5e6890cac2d596d Author: Frederic Weisbecker <fweisbec@xxxxxxxxx> AuthorDate: Mon, 10 Aug 2009 16:11:32 +0200 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Mon, 10 Aug 2009 16:18:50 +0200 perf_counter: Subtract the buffer size field from the event record size We compute the perf raw sample size by aligning the raw ftrace event size plus the buffer size field itself. We do that instead of aligning only the perf raw sample size, so that we might economize some in some cases. But this buffer size field is not stored in the perf raw sample, we must then substract its size from the buffer once we computed the alignment unless we may get a useless u32 field in the buffer. Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Mike Galbraith <efault@xxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> LKML-Reference: <20090810141129.GA5124@nowhere> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- include/trace/ftrace.h | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 7167b9b..a05524f 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -637,7 +637,12 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * pc = preempt_count(); * * __data_size = ftrace_get_offsets_<call>(&__data_offsets, args); - * __entry_size = __data_size + sizeof(*entry); + * + * // Below we want to get the aligned size by taking into account + * // the u32 field that will later store the buffer size + * __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32), + * sizeof(u64)); + * __entry_size -= sizeof(u32); * * do { * char raw_data[__entry_size]; <- allocate our sample in the stack @@ -687,6 +692,7 @@ static void ftrace_profile_##call(proto) \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\ sizeof(u64)); \ + __entry_size -= sizeof(u32); \ \ do { \ char raw_data[__entry_size]; \ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html