Re: [PATCH v4 3/3] memcg: avoid THP split in task migration

On Mon, 12 Mar 2012 18:30:56 -0400
Naoya Horiguchi [off-list ref] wrote:

Currently we can't do task migration among memory cgroups without THP split,
which means processes heavily using THP experience large overhead in task
migration. This patch introduces the code for moving charge of THP and makes
THP more valuable.

Changes from v3:
- use enum mc_target_type and MC_TARGET_* explicitly
- replace lengthy name is_target_thp_for_mc() with get_mctgt_type_thp()
- drop cond_resched()
- drop mapcount check of page sharing (Hugh and KAMEZAWA-san are preparing
  patches to change the behavior of moving charge of shared pages, so this
  patch keeps up with the change to avoid potential conflict.)

Changes from v2:
- add move_anon() and mapcount check

Changes from v1:
- rename is_target_huge_pmd_for_mc() to is_target_thp_for_mc()
- remove pmd_present() check (it's buggy when pmd_trans_huge(pmd) is true)
- is_target_thp_for_mc() calls get_page() only when checks are passed
- unlock page table lock if !mc.precharge
- compare return value of is_target_thp_for_mc() explicitly to MC_TARGET_TYPE
- clean up &walk->mm->page_table_lock to &vma->vm_mm->page_table_lock
- add comment about why race with split_huge_page() does not happen

Signed-off-by: Naoya Horiguchi <redacted>
Acked-by: Hillf Danton <redacted>

Thank you.

Acked-by: KAMEZAWA Hiroyuki <redacted>


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>