[PATCH 0/2] perf,coresight: Reduce fragmentation with non-contiguous AUX pages for cs_etm

[Yabin Cui <yabinc@google.com>]

Hi perf maintainers,
Hi coresight maintainers,

This patch set (2 patches) addresses memory fragmentation caused by
contiguous AUX buffer allocation for the cs_etm PMU on Android.

The cs_etm PMU doesn't need contiguous AUX pages, yet perf always allocates
contiguous AUX pages based on aux_watermark. So repeated use of cs_etm
with large buffers leads to memory fragmentation, negatively impacting
other processes.

This solution introduces PERF_PMU_CAP_AUX_NON_CONTIGUOUS_PAGES to allow
cs_etm to request non-contiguous AUX buffers, avoiding high-order page
allocations and reducing fragmentation.

This aims to reduce memory fragmentation for Android devices when using
cs_etm. Your review is appreciated.

Thanks,
Yabin


Yabin Cui (2):
  perf: Allow non-contiguous AUX buffer pages via PMU capability
  coresight: etm-perf: Add AUX_NON_CONTIGUOUS_PAGES to cs_etm PMU

 drivers/hwtracing/coresight/coresight-etm-perf.c | 3 ++-
 include/linux/perf_event.h                       | 1 +
 kernel/events/ring_buffer.c                      | 6 ++++++
 3 files changed, 9 insertions(+), 1 deletion(-)

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2.49.0.805.g082f7c87e0-goog