| Message ID | 20241019023716.4516-5-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | refine storing NULL | expand |
* Wei Yang <richard.weiyang@gmail.com> [241018 22:37]: > Currently, when storing NULL on mas_store_root(), the behavior could be > improved. > > For example possible cases are: > > * store NULL at any range result a new node > * store NULL at range [m, n] where m > 0 to a single entry tree result > a new node with range [m, n] set to NULL > * store NULL at range [m, n] where m > 0 to an empty tree result > consecutive NULL slot > * it allows for multiple NULL entries by expanding root to > store NULLs to an empty tree > > This patch tries to improve in: > > * memory efficient by setting to empty tree instead of using a node > * remove the possibility of consecutive NULL slot which will prohibit > extended null in later operation > > Signed-off-by: Wei Yang <richard.weiyang@gmail.com> > CC: Liam R. Howlett <Liam.Howlett@Oracle.com> > CC: Sidhartha Kumar <sidhartha.kumar@oracle.com> > CC: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> > > --- > v3: move change into mas_store_root() > v4: add a comment and simplify the logic a little > adjust the change log a little > --- > lib/maple_tree.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/lib/maple_tree.c b/lib/maple_tree.c > index 2226e77c00cb..1205a5208cfe 100644 > --- a/lib/maple_tree.c > +++ b/lib/maple_tree.c > @@ -3439,9 +3439,20 @@ static inline void mas_root_expand(struct ma_state *mas, void *entry) > return; > } > > +/* > + * mas_store_root() - Storing value into root. > + * @mas: The maple state > + * @entry: The entry to store. > + * > + * There is no root node now and we are storing a value into the root - this > + * function either assigns the pointer or expands into a node. > + */ > static inline void mas_store_root(struct ma_state *mas, void *entry) > { > - if (likely((mas->last != 0) || (mas->index != 0))) > + if (!entry) { > + if (!mas->index) > + rcu_assign_pointer(mas->tree->ma_root, NULL); > + } else if (likely((mas->last != 0) || (mas->index != 0))) > mas_root_expand(mas, entry); > else if (((unsigned long) (entry) & 3) == 2) > mas_root_expand(mas, entry); > -- > 2.34.1 >
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 2226e77c00cb..1205a5208cfe 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -3439,9 +3439,20 @@ static inline void mas_root_expand(struct ma_state *mas, void *entry) return; } +/* + * mas_store_root() - Storing value into root. + * @mas: The maple state + * @entry: The entry to store. + * + * There is no root node now and we are storing a value into the root - this + * function either assigns the pointer or expands into a node. + */ static inline void mas_store_root(struct ma_state *mas, void *entry) { - if (likely((mas->last != 0) || (mas->index != 0))) + if (!entry) { + if (!mas->index) + rcu_assign_pointer(mas->tree->ma_root, NULL); + } else if (likely((mas->last != 0) || (mas->index != 0))) mas_root_expand(mas, entry); else if (((unsigned long) (entry) & 3) == 2) mas_root_expand(mas, entry);
Currently, when storing NULL on mas_store_root(), the behavior could be improved. For example possible cases are: * store NULL at any range result a new node * store NULL at range [m, n] where m > 0 to a single entry tree result a new node with range [m, n] set to NULL * store NULL at range [m, n] where m > 0 to an empty tree result consecutive NULL slot * it allows for multiple NULL entries by expanding root to store NULLs to an empty tree This patch tries to improve in: * memory efficient by setting to empty tree instead of using a node * remove the possibility of consecutive NULL slot which will prohibit extended null in later operation Signed-off-by: Wei Yang <richard.weiyang@gmail.com> CC: Liam R. Howlett <Liam.Howlett@Oracle.com> CC: Sidhartha Kumar <sidhartha.kumar@oracle.com> CC: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> --- v3: move change into mas_store_root() v4: add a comment and simplify the logic a little adjust the change log a little --- lib/maple_tree.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)