lkml.org 
[lkml]   [2020]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 00/25] Large pages in the page cache
On Wed, Apr 29, 2020 at 06:36:32AM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> This patch set does not pass xfstests. Test at your own risk. It is
> based on the readahead rewrite which is in Andrew's tree. The large
> pages somehow manage to fall off the LRU, so the test VM quickly runs
> out of memory and freezes. To reproduce:
>
> # mkfs.xfs /dev/sdb && mount /dev/sdb /mnt && dd if=/dev/zero bs=1M count=2048 of=/mnt/bigfile && sync && sleep 2 && sync && echo 1 >/proc/sys/vm/drop_caches
> # /host/home/willy/kernel/xarray-2/tools/vm/page-types | grep thp
> 0x0000000000401800 511 1 ___________Ma_________t____________________ mmap,anonymous,thp
> 0x0000000000405868 1 0 ___U_lA____Ma_b_______t____________________ uptodate,lru,active,mmap,anonymous,swapbacked,thp
> # dd if=/mnt/bigfile of=/dev/null bs=2M count=5
> # /host/home/willy/kernel/xarray-2/tools/vm/page-types | grep thp
> 0x0000000000400000 2516 9 ______________________t____________________ thp
> 0x0000000000400028 1 0 ___U_l________________t____________________ uptodate,lru,thp
> 0x000000000040006c 106 0 __RU_lA_______________t____________________ referenced,uptodate,lru,active,thp

Note that you have 107 pages on LRU. It is only head pages. With order-5
pages it is over 13MiB.

Looks like everything is fine.

> 0x0000000000400228 1 0 ___U_l___I____________t____________________ uptodate,lru,reclaim,thp
> 0x0000000000401800 511 1 ___________Ma_________t____________________ mmap,anonymous,thp
> 0x0000000000405868 1 0 ___U_lA____Ma_b_______t____________________ uptodate,lru,active,mmap,anonymous,swapbacked,thp
>
>
> The principal idea here is that a large part of the overhead in dealing
> with individual pages is that there's just so darned many of them. We
> would be better off dealing with fewer, larger pages, even if they don't
> get to be the size necessary for the CPU to use a larger TLB entry.
>
> Matthew Wilcox (Oracle) (24):
> mm: Allow hpages to be arbitrary order
> mm: Introduce thp_size
> mm: Introduce thp_order
> mm: Introduce offset_in_thp
> fs: Add a filesystem flag for large pages
> fs: Introduce i_blocks_per_page
> fs: Make page_mkwrite_check_truncate thp-aware
> fs: Support THPs in zero_user_segments
> bio: Add bio_for_each_thp_segment_all
> iomap: Support arbitrarily many blocks per page
> iomap: Support large pages in iomap_adjust_read_range
> iomap: Support large pages in read paths
> iomap: Support large pages in write paths
> iomap: Inline data shouldn't see large pages
> xfs: Support large pages
> mm: Make prep_transhuge_page return its argument
> mm: Add __page_cache_alloc_order
> mm: Allow large pages to be added to the page cache
> mm: Allow large pages to be removed from the page cache
> mm: Remove page fault assumption of compound page size
> mm: Add DEFINE_READAHEAD
> mm: Make page_cache_readahead_unbounded take a readahead_control
> mm: Make __do_page_cache_readahead take a readahead_control
> mm: Add large page readahead
>
> William Kucharski (1):
> mm: Align THP mappings for non-DAX
>
> drivers/nvdimm/btt.c | 4 +-
> drivers/nvdimm/pmem.c | 6 +-
> fs/ext4/verity.c | 4 +-
> fs/f2fs/verity.c | 4 +-
> fs/iomap/buffered-io.c | 110 ++++++++++++++++--------------
> fs/jfs/jfs_metapage.c | 2 +-
> fs/xfs/xfs_aops.c | 4 +-
> fs/xfs/xfs_super.c | 2 +-
> include/linux/bio.h | 13 ++++
> include/linux/bvec.h | 23 +++++++
> include/linux/fs.h | 1 +
> include/linux/highmem.h | 15 +++--
> include/linux/huge_mm.h | 25 +++++--
> include/linux/mm.h | 97 ++++++++++++++-------------
> include/linux/pagemap.h | 62 ++++++++++++++---
> mm/filemap.c | 60 ++++++++++++-----
> mm/highmem.c | 62 ++++++++++++++++-
> mm/huge_memory.c | 49 ++++++--------
> mm/internal.h | 13 ++--
> mm/memory.c | 7 +-
> mm/page_io.c | 2 +-
> mm/page_vma_mapped.c | 4 +-
> mm/readahead.c | 145 ++++++++++++++++++++++++++++++----------
> 23 files changed, 485 insertions(+), 229 deletions(-)
>
> --
> 2.26.2
>

--
Kirill A. Shutemov

\
 
 \ /
  Last update: 2020-04-29 17:40    [W:0.248 / U:0.188 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site