diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-06-07 21:08:44 +0100 |
|---|---|---|
| committer | Denys Drozdov <denys.drozdov@toradex.com> | 2021-07-15 13:54:28 +0300 |
| commit | 7dca0665b5639e87ce167831b7810be32d2ba72a (patch) | |
| tree | 3a4a75275fed60322caf9229bd84e271914bb6b5 /Documentation | |
| parent | f481a8160be5efc7cd1973b48da84ebd5da7c623 (diff) | |
XArray: add xas_split
commit 8fc75643c5e14574c8be59b69182452ece28315a upstream
In order to use multi-index entries for huge pages in the page cache, we
need to be able to split a multi-index entry (eg if a file is truncated in
the middle of a huge page entry). This version does not support splitting
more than one level of the tree at a time. This is an acceptable
limitation for the page cache as we do not expect to support order-12
pages in the near future.
[akpm@linux-foundation.org: export xas_split_alloc() to modules]
[willy@infradead.org: fix xarray split]
Link: https://lkml.kernel.org/r/20200910175450.GV6583@casper.infradead.org
[willy@infradead.org: fix xarray]
Link: https://lkml.kernel.org/r/20201001233943.GW20115@casper.infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Qian Cai <cai@lca.pw>
Cc: Song Liu <songliubraving@fb.com>
Link: https://lkml.kernel.org/r/20200903183029.14930-3-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/core-api/xarray.rst | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index fcedc5349ace..2ad3c1fce579 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -461,13 +461,15 @@ or iterations will move the index to the first index in the range. Each entry will only be returned once, no matter how many indices it occupies. -Using xas_next() or xas_prev() with a multi-index xa_state -is not supported. Using either of these functions on a multi-index entry -will reveal sibling entries; these should be skipped over by the caller. - -Storing ``NULL`` into any index of a multi-index entry will set the entry -at every index to ``NULL`` and dissolve the tie. Splitting a multi-index -entry into entries occupying smaller ranges is not yet supported. +Using xas_next() or xas_prev() with a multi-index xa_state is not +supported. Using either of these functions on a multi-index entry will +reveal sibling entries; these should be skipped over by the caller. + +Storing ``NULL`` into any index of a multi-index entry will set the +entry at every index to ``NULL`` and dissolve the tie. A multi-index +entry can be split into entries occupying smaller ranges by calling +xas_split_alloc() without the xa_lock held, followed by taking the lock +and calling xas_split(). Functions and structures ======================== |