[PATCH 0/2] hugepage: optimize page fault path locking

[Davidlohr Bueso <davidlohr.bueso@hp.com>]

This patchset attempts to reduce the amount of contention we impose
on the hugetlb_instantiation_mutex by replacing the global mutex with
a table of mutexes, selected based on a hash. The original discussion can 
be found here: http://lkml.org/lkml/2013/7/12/428

Patch 1: Allows the file region tracking list to be serialized by its own rwsem.
This is necessary because the next patch allows concurrent hugepage fault paths,
getting rid of the hugetlb_instantiation_mutex - which protects chains of struct 
file_regionin inode->i_mapping->private_list (VM_MAYSHARE) or vma_resv_map(vma)->regions 
(!VM_MAYSHARE).

Patch 2: From David Gibson, for some reason never made it into the kernel. 
Further cleanups and enhancements from Anton Blanchard and myself.
Details of how the hash key is selected is in the patch.

Davidlohr Bueso (2):
  hugepage: protect file regions with rwsem
  hugepage: allow parallelization of the hugepage fault path

 mm/hugetlb.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 106 insertions(+), 28 deletions(-)

-- 
1.7.11.7

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