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Diffstat (limited to 'Documentation/core-api/xarray.rst')
| -rw-r--r-- | Documentation/core-api/xarray.rst | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index a4e705108f42..65c77a81b689 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -105,6 +105,15 @@ may result in the entry being marked at some, but not all of the other indices. Storing into one index may result in the entry retrieved by some, but not all of the other indices changing. +Sometimes you need to ensure that a subsequent call to :c:func:`xa_store` +will not need to allocate memory. The :c:func:`xa_reserve` function +will store a reserved entry at the indicated index. Users of the normal +API will see this entry as containing ``NULL``. If you do not need to +use the reserved entry, you can call :c:func:`xa_release` to remove the +unused entry. If another user has stored to the entry in the meantime, +:c:func:`xa_release` will do nothing; if instead you want the entry to +become ``NULL``, you should use :c:func:`xa_erase`. + Finally, you can remove all entries from an XArray by calling :c:func:`xa_destroy`. If the XArray entries are pointers, you may wish to free the entries first. You can do this by iterating over all present @@ -167,6 +176,9 @@ Takes xa_lock internally: * :c:func:`xa_alloc` * :c:func:`xa_alloc_bh` * :c:func:`xa_alloc_irq` + * :c:func:`xa_reserve` + * :c:func:`xa_reserve_bh` + * :c:func:`xa_reserve_irq` * :c:func:`xa_destroy` * :c:func:`xa_set_mark` * :c:func:`xa_clear_mark` @@ -177,6 +189,7 @@ Assumes xa_lock held on entry: * :c:func:`__xa_erase` * :c:func:`__xa_cmpxchg` * :c:func:`__xa_alloc` + * :c:func:`__xa_reserve` * :c:func:`__xa_set_mark` * :c:func:`__xa_clear_mark` |