Re: [PATCH, RFC 00/16] Transparent huge page cache

[Simon Jeons <simon.jeons@gmail.com>]

On 01/28/2013 05:24 PM, Kirill A. Shutemov wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
>
> Here's first steps towards huge pages in page cache.
>
> The intend of the work is get code ready to enable transparent huge page
> cache for the most simple fs -- ramfs.
>
> It's not yet near feature-complete. It only provides basic infrastructure.
> At the moment we can read, write and truncate file on ramfs with huge pages in
> page cache. The most interesting part, mmap(), is not yet there. For now
> we split huge page on mmap() attempt.
>
> I can't say that I see whole picture. I'm not sure if I understand locking
> model around split_huge_page(). Probably, not.
> Andrea, could you check if it looks correct?

Is there any thp performance test benchmark? For anonymous pages or file 
pages.

>
> Next steps (not necessary in this order):
>   - mmap();
>   - migration (?);
>   - collapse;
>   - stats, knobs, etc.;
>   - tmpfs/shmem enabling;
>   - ...
>
> Kirill A. Shutemov (16):
>    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: basic defines for transparent huge page cache
>    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: 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
>      simple_read/write_begin/write_end
>    thp: handle file pages in split_huge_page()
>    thp, mm: truncate support for transparent huge page cache
>    thp, mm: split huge page on mmap file page
>    ramfs: enable transparent huge page cache
>
>   fs/libfs.c                  |   54 +++++++++---
>   fs/ramfs/inode.c            |    6 +-
>   include/linux/backing-dev.h |   10 +++
>   include/linux/huge_mm.h     |    8 ++
>   include/linux/mm.h          |   15 ++++
>   include/linux/pagemap.h     |   14 ++-
>   include/linux/radix-tree.h  |    3 +
>   lib/radix-tree.c            |   32 +++++--
>   mm/filemap.c                |  204 +++++++++++++++++++++++++++++++++++--------
>   mm/huge_memory.c            |   62 +++++++++++--
>   mm/memory.c                 |   22 +++++
>   mm/truncate.c               |   12 +++
>   12 files changed, 375 insertions(+), 67 deletions(-)
>