> On Oct 26, 2020, at 9:18 AM, Matthew Wilcox (Oracle) <[email protected]>
> wrote:
>
> We actually use nrexceptional for very little these days. It's a minor
> pain to keep in sync with nrpages, but the pain becomes much bigger
> with the THP patches because we don't know how many indices a shadow
> entry occupies. It's easier to just remove it than keep it accurate.
>
> Also, we save 8 bytes per inode which is nothing to sneeze at; on my
> laptop, it would improve shmem_inode_cache from 22 to 23 objects per
> 16kB, and inode_cache from 26 to 27 objects. Combined, that saves
> a megabyte of memory from a combined usage of 25MB for both caches.
> Unfortunately, ext4 doesn't cross a magic boundary, so it doesn't save
> any memory for ext4.
>
> Matthew Wilcox (Oracle) (4):
> mm: Introduce and use mapping_empty
> mm: Stop accounting shadow entries
> dax: Account DAX entries as nrpages
> mm: Remove nrexceptional from inode
>
> fs/block_dev.c | 2 +-
> fs/dax.c | 8 ++++----
> fs/gfs2/glock.c | 3 +--
> fs/inode.c | 2 +-
> include/linux/fs.h | 2 --
> include/linux/pagemap.h | 5 +++++
> mm/filemap.c | 16 ----------------
> mm/swap_state.c | 4 ----
> mm/truncate.c | 19 +++----------------
> mm/workingset.c | 1 -
> 10 files changed, 15 insertions(+), 47 deletions(-)
>
> --
> 2.28.0
Looks good to me.
Reviewed-by: William Kucharski <[email protected]>
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