This patch set has gone through several revisions as an RFC which
is documented in the log below. The major change in this version
is the addition of code to handle the region_chg/region_add calling
sequence with the addition of fallocate hole punch. This is the
first patch in the series. As suggested during the RFC process,
tests have been proposed to libhugetlbfs as described at:
http://librelist.com/browser//libhugetlbfs/2015/6/25/patch-tests-add-tests-for-fallocate-system-call/
fallocate(2) man page modifications are also necessary to specify
that fallocate for hugetlbfs only operates on whole pages. This
change will be submitted once the code has stabalized and been
proposed for merging.
hugetlbfs is used today by applications that want a high degree of
control over huge page usage. Often, large hugetlbfs files are used
to map a large number huge pages into the application processes.
The applications know when page ranges within these large files will
no longer be used, and ideally would like to release them back to
the subpool or global pools for other uses. The fallocate() system
call provides an interface for preallocation and hole punching within
files. This patch set adds fallocate functionality to hugetlbfs.
v1:
Add a cache of region descriptors to the resv_map for use by
region_add in case hole punch deletes entries necessary for
a successful operation.
RFC v4:
Removed alloc_huge_page/hugetlb_reserve_pages race patches as already
in mmotm
Moved hugetlb_fix_reserve_counts in series as suggested by Naoya Horiguchi
Inline'ed hugetlb_fault_mutex routines as suggested by Davidlohr Bueso and
existing code changed to use new interfaces as suggested by Naoya
fallocate preallocation code cleaned up and made simpler
Modified alloc_huge_page to handle special case where allocation is
for a hole punched area with spool reserves
RFC v3:
Folded in patch for alloc_huge_page/hugetlb_reserve_pages race
in current code
fallocate allocation and hole punch is synchronized with page
faults via existing mutex table
hole punch uses existing hugetlb_vmtruncate_list instead of more
generic unmap_mapping_range for unmapping
Error handling for the case when region_del() fauils
RFC v2:
Addressed alignment and error handling issues noticed by Hillf Danton
New region_del() routine for region tracking/resv_map of ranges
Fixed several issues found during more extensive testing
Error handling in region_del() when kmalloc() fails stills needs
to be addressed
madvise remove support remains
Mike Kravetz (10):
mm/hugetlb: add cache of descriptors to resv_map for region_add
mm/hugetlb: add region_del() to delete a specific range of entries
mm/hugetlb: expose hugetlb fault mutex for use by fallocate
hugetlbfs: hugetlb_vmtruncate_list() needs to take a range to delete
hugetlbfs: truncate_hugepages() takes a range of pages
mm/hugetlb: vma_has_reserves() needs to handle fallocate hole punch
mm/hugetlb: alloc_huge_page handle areas hole punched by fallocate
hugetlbfs: New huge_add_to_page_cache helper routine
hugetlbfs: add hugetlbfs_fallocate()
mm: madvise allow remove operation for hugetlbfs
fs/hugetlbfs/inode.c | 281 +++++++++++++++++++++++++++++---
include/linux/hugetlb.h | 17 +-
mm/hugetlb.c | 422 ++++++++++++++++++++++++++++++++++++++----------
mm/madvise.c | 2 +-
4 files changed, 618 insertions(+), 104 deletions(-)
--
2.1.0
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