[RFC v5 PATCH 0/9] hugetlbfs: add fallocate support

From: Mike Kravetz
Date: Mon Jun 22 2015 - 20:40:32 EST

No major changes since last RFC. Externalized existing hugetlb
fault mutex code. Added more comments to alloc_huge_page reservation
handling as I could not come up with a good way to encapsulate.
libhugetlbfs test cases and man page updates will be included with
a later request for patch inclusion.

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.

RFC v5:
Simply made existing hugetlb fault mutex hash routine available for
use by fallocate.
Unable to come up with good reservation encapsulation routines for
alloc_huge_page, so attempted to comment better.
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() fails
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 (9):
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 | 14 ++-
mm/hugetlb.c | 245 +++++++++++++++++++++++++++++------------
mm/madvise.c | 2 +-
4 files changed, 456 insertions(+), 86 deletions(-)


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
Please read the FAQ at http://www.tux.org/lkml/