[LTP] [PATCH v1 0/4] sched/psi: Add tests for PSI interface

[Samir Mulani]

This patch series adds four new test cases for the Linux kernel's
Pressure Stall Information (PSI) interface (/proc/pressure/{cpu,memory,io}).

Currently, LTP lacks dedicated test coverage for PSI functionality, trigger
parsing rules, and stall accounting. These tests ensure kernel compliance
and validate PSI behavior.

Test series breakdown:
  1. psi_invalid_trigger01 (1/4):
     Tests trigger input validation in /proc/pressure/memory. Checks that
     invalid trigger strings return EINVAL and valid boundary values succeed.

  2. psi_multiple_trigger01 (2/4):
     Tests that only one trigger is allowed per open file description,
     and second triggers on the same or dup()'d file descriptor fail with EBUSY.

  3. psi_proc_format01 (3/4):
     Validates the file format of /proc/pressure/{cpu,memory,io}, ensuring
     percentages are between 0 and 100, totals never decrease, and CPU full
     stall reports 0.00.

  4. psi_accounting01 (4/4):
     Validates real stall accounting within isolated cgroups (cgroup v2)
     for CPU contention, memory throttling via memory.high, and O_DIRECT
     synchronous block I/O stalls.

Samir Mulani (4):
  sched/psi: Add psi_invalid_trigger01 test
  sched/psi: Add psi_multiple_trigger01 test
  sched/psi: Add psi_proc_format01 test
  sched/psi: Add psi_accounting01 test

 runtest/sched                                 |   5 +
 testcases/kernel/sched/psi/.gitignore         |   4 +
 testcases/kernel/sched/psi/Makefile           |   7 +
 testcases/kernel/sched/psi/psi_accounting01.c | 356 ++++++++++++++++++
 .../kernel/sched/psi/psi_invalid_trigger01.c  | 135 +++++++
 .../kernel/sched/psi/psi_multiple_trigger01.c | 172 +++++++++
 .../kernel/sched/psi/psi_proc_format01.c      | 191 ++++++++++
 7 files changed, 870 insertions(+)
 create mode 100644 testcases/kernel/sched/psi/.gitignore
 create mode 100644 testcases/kernel/sched/psi/Makefile
 create mode 100644 testcases/kernel/sched/psi/psi_accounting01.c
 create mode 100644 testcases/kernel/sched/psi/psi_invalid_trigger01.c
 create mode 100644 testcases/kernel/sched/psi/psi_multiple_trigger01.c
 create mode 100644 testcases/kernel/sched/psi/psi_proc_format01.c

-- 
2.53.0