)]}'
{
  "commit": "e78bbfa8262424417a29349a8064a535053912b9",
  "tree": "dc1f1cdd4390b3f817a2d3a2835c11eb3b41b3ea",
  "parents": [
    "de7f0cba96786cf9ec9da4532c1b25f733da9b6f"
  ],
  "author": {
    "name": "Brice Goglin",
    "email": "Brice.Goglin@inria.fr",
    "time": "Sat Oct 18 20:27:15 2008 -0700"
  },
  "committer": {
    "name": "Linus Torvalds",
    "email": "torvalds@linux-foundation.org",
    "time": "Mon Oct 20 08:52:33 2008 -0700"
  },
  "message": "mm: stop returning -ENOENT from sys_move_pages() if nothing got migrated\n\nA patchset reworking sys_move_pages().  It removes the possibly large\nvmalloc by using multiple chunks when migrating large buffers.  It also\ndramatically increases the throughput for large buffers since the lookup\nin new_page_node() is now limited to a single chunk, causing the quadratic\ncomplexity to have a much slower impact.  There is no need to use any\nradix-tree-like structure to improve this lookup.\n\nsys_move_pages() duration on a 4-quadcore-opteron 2347HE (1.9Gz),\nmigrating between nodes #2 and #3:\n\n\tlength\t\tmove_pages (us)\t\tmove_pages+patch (us)\n\t4kB\t\t126\t\t\t98\n\t40kB\t\t198\t\t\t168\n\t400kB\t\t963\t\t\t937\n\t4MB\t\t12503\t\t\t11930\n\t40MB\t\t246867\t\t\t11848\n\nPatches #1 and #4 are the important ones:\n1) stop returning -ENOENT from sys_move_pages() if nothing got migrated\n2) don\u0027t vmalloc a huge page_to_node array for do_pages_stat()\n3) extract do_pages_move() out of sys_move_pages()\n4) rework do_pages_move() to work on page_sized chunks\n5) move_pages: no need to set pp-\u003epage to ZERO_PAGE(0) by default\n\nThis patch:\n\nThere is no point in returning -ENOENT from sys_move_pages() if all pages\nwere already on the right node, while we return 0 if only 1 page was not.\nMost application don\u0027t know where their pages are allocated, so it\u0027s not\nan error to try to migrate them anyway.\n\nJust return 0 and let the status array in user-space be checked if the\napplication needs details.\n\nIt will make the upcoming chunked-move_pages() support much easier.\n\nSigned-off-by: Brice Goglin \u003cBrice.Goglin@inria.fr\u003e\nAcked-by: Christoph Lameter \u003ccl@linux-foundation.org\u003e\nCc: Nick Piggin \u003cnickpiggin@yahoo.com.au\u003e\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "6802a7a3dfecc71f4e822e5eee2a12b293edba37",
      "old_mode": 33188,
      "old_path": "mm/migrate.c",
      "new_id": "f233519f0453472496c6c024c94335be171b7a39",
      "new_mode": 33188,
      "new_path": "mm/migrate.c"
    }
  ]
}