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Message-ID: <20240425220509.1751260-1-yabinc@google.com>
Date: Thu, 25 Apr 2024 15:05:09 -0700
From: Yabin Cui <yabinc@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>
Cc: linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Yabin Cui <yabinc@...gle.com>
Subject: [PATCH] perf/core: Trim dyn_size if raw data is absent
Currently, perf_tp_event() always allocates space for raw sample data,
even when the PERF_SAMPLE_RAW flag is not set. This leads to unused
spaces within generated sample records.
This patch reduces dyn_size when PERF_SAMPLE_RAW is not present,
ensuring sample records use only the necessary amount of space.
Fixes: 0a9081cf0a11 ("perf/core: Add perf_sample_save_raw_data() helper")
Signed-off-by: Yabin Cui <yabinc@...gle.com>
---
kernel/events/core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 724e6d7e128f..d68ecdc264d3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7688,6 +7688,10 @@ void perf_prepare_sample(struct perf_sample_data *data,
data->raw = NULL;
data->dyn_size += sizeof(u64);
data->sample_flags |= PERF_SAMPLE_RAW;
+ } else if ((data->sample_flags & ~sample_type) & PERF_SAMPLE_RAW) {
+ data->dyn_size -= data->raw->size + sizeof(u32);
+ data->raw = NULL;
+ data->sample_flags &= ~PERF_SAMPLE_RAW;
}
if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) {
--
2.44.0.769.g3c40516874-goog
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