)]}'
{
  "commit": "fc6738c778a803029ad5712901dcb0c00394dad4",
  "tree": "c6819de68cbc50f5ff0a0f1324f5cd98e8928ac9",
  "parents": [
    "d1830d122e2016ffd1557d6341821182a0dd7f45"
  ],
  "author": {
    "name": "Tejun Heo",
    "email": "tj@kernel.org",
    "time": "Thu Dec 29 17:02:51 2016 -0500"
  },
  "committer": {
    "name": "Tejun Heo",
    "email": "tj@kernel.org",
    "time": "Thu Dec 29 17:02:51 2016 -0500"
  },
  "message": "cgroup: call subsys-\u003e*attach() only for subsystems which are actually affected by migration\n\nCurrently, subsys-\u003e*attach() callbacks are called for all subsystems\nwhich are attached to the hierarchy on which the migration is taking\nplace.\n\nWith cgroup_migrate_prepare_dst() filtering out identity migrations,\nv1 hierarchies can avoid spurious -\u003e*attach() callback invocations\nwhere the source and destination csses are identical; however, this\nisn\u0027t enough on v2 as only a subset of the attached controllers can be\naffected on controller enable/disable.\n\nWhile spurious -\u003e*attach() invocations aren\u0027t critically broken,\nthey\u0027re unnecessary overhead and can lead to temporary overcharges on\ncertain controllers.  Fix it by tracking which subsystems are affected\nby a migration and invoking -\u003e*attach() callbacks only on those\nsubsystems.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "5f8c8ac5ab88360ecc7739d350d4efb20416e377",
      "old_mode": 33188,
      "old_path": "kernel/cgroup/cgroup-internal.h",
      "new_id": "9203bfb0560399af9611bd40516758ab01076cba",
      "new_mode": 33188,
      "new_path": "kernel/cgroup/cgroup-internal.h"
    },
    {
      "type": "modify",
      "old_id": "7a965f460faf9e898ec50ec476556c249871eb0b",
      "old_mode": 33188,
      "old_path": "kernel/cgroup/cgroup-v1.c",
      "new_id": "fc34bcf2329f4dbc625ce2e3579a9454fb0ce5e5",
      "new_mode": 33188,
      "new_path": "kernel/cgroup/cgroup-v1.c"
    },
    {
      "type": "modify",
      "old_id": "f90554d24e591e451ce809926fe2a9847376a06a",
      "old_mode": 33188,
      "old_path": "kernel/cgroup/cgroup.c",
      "new_id": "69ad5b3de0c1b94545600e909fbae2bc8cd72d01",
      "new_mode": 33188,
      "new_path": "kernel/cgroup/cgroup.c"
    }
  ]
}