maple_tree: replace preallocation with slub percpu array prefill

With the percpu array we can try not doing the preallocations in maple
tree, and instead make sure the percpu array is prefilled, and using
GFP_ATOMIC in places that relied on the preallocation (in case we miss
or fail trylock on the array), i.e. mas_store_prealloc(). For now simply
add __GFP_NOFAIL there as well.

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 1591f3917b7e63eaa1f2183862f320dca6e7e5ff..b21c53cb085d28a5cb86665dde464ffefc00d183 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5428,7 +5428,12 @@ void mas_store_prealloc(struct ma_state *mas, void *entry)
 
        mas_wr_store_setup(&wr_mas);
        trace_ma_write(__func__, mas, 0, entry);
+
+retry:
        mas_wr_store_entry(&wr_mas);
+       if (unlikely(mas_nomem(mas, GFP_ATOMIC | __GFP_NOFAIL)))
+               goto retry;
+
        MAS_WR_BUG_ON(&wr_mas, mas_is_err(mas));
        mas_destroy(mas);
 }
@@ -5447,8 +5452,6 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
        MA_WR_STATE(wr_mas, mas, entry);
        unsigned char node_size;
        int request = 1;
-       int ret;
-
 
        if (unlikely(!mas->index && mas->last == ULONG_MAX))
                goto ask_now;
@@ -5499,16 +5502,8 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
 
        /* node store, slot store needs one node */
 ask_now:
-       mas_node_count_gfp(mas, request, gfp);
-       if (likely(!mas_is_err(mas)))
-               return 0;
+       return kmem_cache_prefill_percpu_array(maple_node_cache, request, gfp);
 
-       mas_set_alloc_req(mas, 0);
-       ret = xa_err(mas->node);
-       mas_reset(mas);
-       mas_destroy(mas);
-       mas_reset(mas);
-       return ret;
 }
 EXPORT_SYMBOL_GPL(mas_preallocate);