On 10/9/23 8:03 PM, Peng Zhang wrote:
Hi, 在 2023/10/10 04:16, Sidhartha Kumar 写道:Preallocate maple nodes before call to mas_wr_store_entry(). If a new node is not needed, go directly to mas_wr_store_entry(), otherwise allocate the needed nodes and set the MA_STATE_PREALLOC flag. Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> --- lib/maple_tree.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index e239197a57fc..25ae66e585f4 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5478,17 +5478,33 @@ int mas_prealloc_calc(struct ma_wr_state *wr_mas) int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp) { MA_WR_STATE(wr_mas, mas, entry); + int request; mas_wr_store_setup(&wr_mas); - trace_ma_write(__func__, mas, 0, entry); -retry: + wr_mas.content = mas_start(mas); + + request = mas_prealloc_calc(&wr_mas);mas_wr_store_entry() does something similar to mas_prealloc_calc(). Now, making it do it twice would incur additional overhead. We encountered this issue while optimizing preallocation, but it hasn't been resolved yet. Previously, this problem only occurred when using mas_preallocate(). Now, this change would bring this impact to all write operations on maple tree. What do you think about it?
After talking to Liam, I will have to implement the store type enum feature on the Maple Tree Work list so that mas_prealloc_calc() can start a partial walk and write that information to the enum. mas_wr_store_entry() can then read that enum to continue the walk that was already started rather than having to redo the whole walk. This could also be used in mas_preallocate(). Do you have any suggestions for the implementation of this enum?
Thanks, Sid
Thanks, Peng+ if (!request) + goto store_entry; + + mas_node_count_gfp(mas, request, gfp); + if (unlikely(mas_is_err(mas))) { + mas_set_alloc_req(mas, 0); + mas_destroy(mas); + mas_reset(mas); + return xa_err(mas->node); + } + mas->mas_flags |= MA_STATE_PREALLOC; + +store_entry: mas_wr_store_entry(&wr_mas); if (unlikely(mas_nomem(mas, gfp))) - goto retry; + goto store_entry; if (unlikely(mas_is_err(mas))) return xa_err(mas->node); + trace_ma_write(__func__, mas, 0, entry); return 0; } EXPORT_SYMBOL_GPL(mas_store_gfp);
