Re: [PATCHv2, RFC 00/30] Transparent huge page cache

From: Simon Jeons
Date: Tue Mar 19 2013 - 21:10:04 EST

Hi Kirill,
On 03/15/2013 01:50 AM, Kirill A. Shutemov wrote:
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>

Here's the second version of the patchset.

The intend of the work is get code ready to enable transparent huge page
cache for the most simple fs -- ramfs.

We have read()/write()/mmap() functionality now. Still plenty work ahead.

It's a great work. But could you give more explanation how you design to implement thp support page cache in order that more developers are easy and happy to review your big patchset?

Any feedback is welcome.

Changes since v1:
- mmap();
- fix add_to_page_cache_locked() and delete_from_page_cache();
- introduce mapping_can_have_hugepages();
- call split_huge_page() only for head page in filemap_fault();
- wait_split_huge_page(): serialize over i_mmap_mutex too;
- lru_add_page_tail: avoid PageUnevictable on active/inactive lru lists;
- fix off-by-one in zero_huge_user_segment();

- memcg accounting has not yet evaluated;
- collapse;
- migration (?);
- stats, knobs, etc.;
- tmpfs/shmem enabling;

Kirill A. Shutemov (30):
block: implement add_bdi_stat()
mm: implement zero_huge_user_segment and friends
mm: drop actor argument of do_generic_file_read()
radix-tree: implement preload for multiple contiguous elements
thp, mm: avoid PageUnevictable on active/inactive lru lists
thp, mm: basic defines for transparent huge page cache
thp, mm: introduce mapping_can_have_hugepages() predicate
thp, mm: rewrite add_to_page_cache_locked() to support huge pages
thp, mm: rewrite delete_from_page_cache() to support huge pages
thp, mm: locking tail page is a bug
thp, mm: handle tail pages in page_cache_get_speculative()
thp, mm: add event counters for huge page alloc on write to a file
thp, mm: implement grab_cache_huge_page_write_begin()
thp, mm: naive support of thp in generic read/write routines
thp, libfs: initial support of thp in
thp: handle file pages in split_huge_page()
thp: wait_split_huge_page(): serialize over i_mmap_mutex too
thp, mm: truncate support for transparent huge page cache
thp, mm: split huge page on mmap file page
ramfs: enable transparent huge page cache
x86-64, mm: proper alignment mappings with hugepages
mm: add huge_fault() callback to vm_operations_struct
thp: prepare zap_huge_pmd() to uncharge file pages
thp: move maybe_pmd_mkwrite() out of mk_huge_pmd()
thp, mm: basic huge_fault implementation for generic_file_vm_ops
thp: extract fallback path from do_huge_pmd_anonymous_page() to a
thp: initial implementation of do_huge_linear_fault()
thp: handle write-protect exception to file-backed huge pages
thp: call __vma_adjust_trans_huge() for file-backed VMA
thp: map file-backed huge pages on fault

arch/x86/kernel/sys_x86_64.c | 13 +-
fs/libfs.c | 50 ++++-
fs/ramfs/inode.c | 6 +-
include/linux/backing-dev.h | 10 +
include/linux/huge_mm.h | 36 +++-
include/linux/mm.h | 16 ++
include/linux/pagemap.h | 24 ++-
include/linux/radix-tree.h | 3 +
include/linux/vm_event_item.h | 2 +
lib/radix-tree.c | 32 ++-
mm/filemap.c | 283 +++++++++++++++++++++----
mm/huge_memory.c | 462 ++++++++++++++++++++++++++++++++++-------
mm/memory.c | 31 ++-
mm/swap.c | 3 +-
mm/truncate.c | 12 ++
mm/vmstat.c | 2 +
16 files changed, 842 insertions(+), 143 deletions(-)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at