)]}'
{
  "commit": "dc86aba751e2867244411adda1562f6664747019",
  "tree": "a3da212be6c190b5585ee4f9761c4177ad4f19c6",
  "parents": [
    "57899a6610e67ba26fa3251ebbef4a5ed21efc5d"
  ],
  "author": {
    "name": "Chengming Zhou",
    "email": "zhouchengming@bytedance.com",
    "time": "Fri Aug 26 00:41:10 2022 +0800"
  },
  "committer": {
    "name": "Peter Zijlstra",
    "email": "peterz@infradead.org",
    "time": "Fri Sep 09 11:08:33 2022 +0200"
  },
  "message": "sched/psi: Cache parent psi_group to speed up group iteration\n\nWe use iterate_groups() to iterate each level psi_group to update\nPSI stats, which is a very hot path.\n\nIn current code, iterate_groups() have to use multiple branches and\ncgroup_parent() to get parent psi_group for each level, which is not\nvery efficient.\n\nThis patch cache parent psi_group in struct psi_group, only need to get\npsi_group of task itself first, then just use group-\u003eparent to iterate.\n\nSigned-off-by: Chengming Zhou \u003czhouchengming@bytedance.com\u003e\nSigned-off-by: Peter Zijlstra (Intel) \u003cpeterz@infradead.org\u003e\nAcked-by: Johannes Weiner \u003channes@cmpxchg.org\u003e\nLink: https://lore.kernel.org/r/20220825164111.29534-10-zhouchengming@bytedance.com\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "40c28171cd91ad0ad56226c0bdefd6ca7735c64c",
      "old_mode": 33188,
      "old_path": "include/linux/psi_types.h",
      "new_id": "a0b746258c682f0ccb68f9108bbc877c8656ca49",
      "new_mode": 33188,
      "new_path": "include/linux/psi_types.h"
    },
    {
      "type": "modify",
      "old_id": "2545a78f82d8dbbdd8924e5e674f761fde4c0fa4",
      "old_mode": 33188,
      "old_path": "kernel/sched/psi.c",
      "new_id": "9a8aee80a0874ab9fd89816a214dac4af887a24f",
      "new_mode": 33188,
      "new_path": "kernel/sched/psi.c"
    }
  ]
}