On 10/25/24 7:58 PM, Wei Yang wrote:
On Fri, Oct 25, 2024 at 03:54:04PM -0400, Sid Kumar wrote:On 10/23/24 9:20 PM, Wei Yang wrote:On Wed, Aug 14, 2024 at 12:19:43PM -0400, Sidhartha Kumar wrote:Users of mas_store_prealloc() enter this function with nodes already preallocated. This means the store type must be already set. We can then remove the call to mas_wr_store_type() and initialize the write state to continue the partial walk that was done when determining the store type.May I ask what is the partial walk here means? It is the mas_wr_walk() in mas_wr_store_type() which is stopped because of it is spanning write?Yes, this is what I meant by the partial walk that's already been started. It's the walk done by mas_wr_store_type().I may lost some background, so the assumption here is mas_wr_store_type() has already been invoked and the store type has been decided, right?Ya users of mas_store_prealloc() should have already called mas_preallocate() which does: mas->store_type = mas_wr_store_type(&wr_mas); request = mas_prealloc_calc(&wr_mas, entry); to set the store type and allocate the nodes.Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> --- lib/maple_tree.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 8c1a1a483395..73ce63d9c3a0 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -3979,9 +3979,6 @@ static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas) wr_mas->end_piv = wr_mas->pivots[wr_mas->offset_end]; else wr_mas->end_piv = wr_mas->mas->max; - - if (!wr_mas->entry) - mas_wr_extend_null(wr_mas); } static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas) @@ -5532,8 +5529,19 @@ void mas_store_prealloc(struct ma_state *mas, void *entry) { MA_WR_STATE(wr_mas, mas, entry); - mas_wr_prealloc_setup(&wr_mas); - mas_wr_store_type(&wr_mas); + if (mas->store_type == wr_store_root) { + mas_wr_prealloc_setup(&wr_mas); + goto store; + } + + mas_wr_walk_descend(&wr_mas);This one does not descend the tree, just locate the offset in a node and adjust min/max. So not look like to continue the partial walk to me.+ if (mas->store_type != wr_spanning_store) { + /* set wr_mas->content to current slot */ + wr_mas.content = mas_slot_locked(mas, wr_mas.slots, mas->offset); + mas_wr_end_piv(&wr_mas);If not a spanning write, the previous walk should reach a leaf node, right?Ya that's true.I am not sure why we don't need to check extend null here. Because we have already done it?Ya we extend null in mas_wr_store_type() which has already been called at this point. /* At this point, we are at the leaf node that needs to be altered. */ mas_wr_end_piv(wr_mas); if (!wr_mas->entry) mas_wr_extend_null(wr_mas); Thanks,Hmm... if we have already done this, why we need to do mas_wr_end_piv() again?
The maple write state here is local to this function:
void mas_store_prealloc(struct ma_state *mas, void *entry)
{
MA_WR_STATE(wr_mas, mas, entry);
so we don't retain the wr_end information from the previous call to
mas_preallocate() and have to repeat it here. The write state is not
currently exposed so have to call mas_wr_end_piv() again.
Thanks, Sid
Sid+ } + +store: trace_ma_write(__func__, mas, 0, entry); mas_wr_store_entry(&wr_mas); MAS_WR_BUG_ON(&wr_mas, mas_is_err(mas)); -- 2.46.0
