There is limited visibility into the percpu memory allocator making it hard to understand usage patterns. Without these concrete numbers, we are left to conjecture about the correctness of percpu memory patterns and usage. Additionally, there is no mechanism to review the correctness/efficiency of the current implementation. This patchset address the following: - Adds basic statistics to reason about the number of allocations over the lifetime, allocation sizes, and fragmentation. - Adds tracepoints to enable better debug capabilities as well as the ability to review allocation requests and corresponding decisions. This patchiest contains the following four patches: 0001-percpu-add-missing-lockdep_assert_held-to-func-pcpu_.patch 0002-percpu-migrate-percpu-data-structures-to-internal-he.patch 0003-percpu-expose-statistics-about-percpu-memory-via-deb.patch 0004-percpu-add-tracepoint-support-for-percpu-memory.patch 0001 adds a missing lockdep_assert_held for pcpu_lock to improve consistency and safety. 0002 prepares for the following patches by moving the definition of data structures and exposes previously static variables. 0003 adds percpu statistics via debugfs. 0004 adds tracepoints to key percpu events: chunk creation/deletion and area allocation/free/failure. This patchset is on top of linus#master 1132d5e. diffstats below: percpu: add missing lockdep_assert_held to func pcpu_free_area percpu: migrate percpu data structures to internal header percpu: expose statistics about percpu memory via debugfs percpu: add tracepoint support for percpu memory include/trace/events/percpu.h | 125 ++++++++++++++++++++++++ mm/Kconfig | 8 ++ mm/Makefile | 1 + mm/percpu-internal.h | 164 +++++++++++++++++++++++++++++++ mm/percpu-km.c | 6 ++ mm/percpu-stats.c | 222 ++++++++++++++++++++++++++++++++++++++++++ mm/percpu-vm.c | 7 ++ mm/percpu.c | 53 +++++----- 8 files changed, 563 insertions(+), 23 deletions(-) create mode 100644 include/trace/events/percpu.h create mode 100644 mm/percpu-internal.h create mode 100644 mm/percpu-stats.c Thanks, Dennis -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
