From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> commit 541e06b772c1aaffb3b6a245ccface36d7107af2 upstream. Preallocations are common in the VMA code to avoid allocating under certain locking conditions. The preallocations must also cover the worst-case scenario. Removing the GFP_ZERO flag from the kmem_cache_alloc() (and bulk variant) calls will reduce the amount of time spent zeroing memory that may not be used. Only zero out the necessary area to keep track of the allocations in the maple state. Zero the entire node prior to using it in the tree. This required internal changes to node counting on allocation, so the test code is also updated. This restores some micro-benchmark performance: up to +9% in mmtests mmap1 by my testing +10% to +20% in mmap, mmapaddr, mmapmany tests reported by Red Hat Link: https://bugzilla.redhat.com/show_bug.cgi?id=2149636 Link: https://lkml.kernel.org/r/20230105160427.2988454-1-Liam.Howlett@xxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam Howlett <Liam.Howlett@xxxxxxxxxx> Reported-by: Jirka Hladky <jhladky@xxxxxxxxxx> Suggested-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/maple_tree.c | 80 ++++++++++++++++++++------------------- tools/testing/radix-tree/maple.c | 18 ++++---- 2 files changed, 52 insertions(+), 46 deletions(-) --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -149,13 +149,12 @@ struct maple_subtree_state { /* Functions */ static inline struct maple_node *mt_alloc_one(gfp_t gfp) { - return kmem_cache_alloc(maple_node_cache, gfp | __GFP_ZERO); + return kmem_cache_alloc(maple_node_cache, gfp); } static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes) { - return kmem_cache_alloc_bulk(maple_node_cache, gfp | __GFP_ZERO, size, - nodes); + return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes); } static inline void mt_free_bulk(size_t size, void __rcu **nodes) @@ -1128,9 +1127,10 @@ static inline struct maple_node *mas_pop { struct maple_alloc *ret, *node = mas->alloc; unsigned long total = mas_allocated(mas); + unsigned int req = mas_alloc_req(mas); /* nothing or a request pending. */ - if (unlikely(!total)) + if (WARN_ON(!total)) return NULL; if (total == 1) { @@ -1140,27 +1140,25 @@ static inline struct maple_node *mas_pop goto single_node; } - if (!node->node_count) { + if (node->node_count == 1) { /* Single allocation in this node. */ mas->alloc = node->slot[0]; - node->slot[0] = NULL; mas->alloc->total = node->total - 1; ret = node; goto new_head; } - node->total--; - ret = node->slot[node->node_count]; - node->slot[node->node_count--] = NULL; + ret = node->slot[--node->node_count]; + node->slot[node->node_count] = NULL; single_node: new_head: - ret->total = 0; - ret->node_count = 0; - if (ret->request_count) { - mas_set_alloc_req(mas, ret->request_count + 1); - ret->request_count = 0; + if (req) { + req++; + mas_set_alloc_req(mas, req); } + + memset(ret, 0, sizeof(*ret)); return (struct maple_node *)ret; } @@ -1179,21 +1177,20 @@ static inline void mas_push_node(struct unsigned long count; unsigned int requested = mas_alloc_req(mas); - memset(reuse, 0, sizeof(*reuse)); count = mas_allocated(mas); - if (count && (head->node_count < MAPLE_ALLOC_SLOTS - 1)) { - if (head->slot[0]) - head->node_count++; - head->slot[head->node_count] = reuse; + reuse->request_count = 0; + reuse->node_count = 0; + if (count && (head->node_count < MAPLE_ALLOC_SLOTS)) { + head->slot[head->node_count++] = reuse; head->total++; goto done; } reuse->total = 1; if ((head) && !((unsigned long)head & 0x1)) { - head->request_count = 0; reuse->slot[0] = head; + reuse->node_count = 1; reuse->total += head->total; } @@ -1212,7 +1209,6 @@ static inline void mas_alloc_nodes(struc { struct maple_alloc *node; unsigned long allocated = mas_allocated(mas); - unsigned long success = allocated; unsigned int requested = mas_alloc_req(mas); unsigned int count; void **slots = NULL; @@ -1228,24 +1224,29 @@ static inline void mas_alloc_nodes(struc WARN_ON(!allocated); } - if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS - 1) { + if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS) { node = (struct maple_alloc *)mt_alloc_one(gfp); if (!node) goto nomem_one; - if (allocated) + if (allocated) { node->slot[0] = mas->alloc; + node->node_count = 1; + } else { + node->node_count = 0; + } - success++; mas->alloc = node; + node->total = ++allocated; requested--; } node = mas->alloc; + node->request_count = 0; while (requested) { max_req = MAPLE_ALLOC_SLOTS; - if (node->slot[0]) { - unsigned int offset = node->node_count + 1; + if (node->node_count) { + unsigned int offset = node->node_count; slots = (void **)&node->slot[offset]; max_req -= offset; @@ -1259,15 +1260,13 @@ static inline void mas_alloc_nodes(struc goto nomem_bulk; node->node_count += count; - /* zero indexed. */ - if (slots == (void **)&node->slot) - node->node_count--; - - success += count; + allocated += count; node = node->slot[0]; + node->node_count = 0; + node->request_count = 0; requested -= count; } - mas->alloc->total = success; + mas->alloc->total = allocated; return; nomem_bulk: @@ -1276,7 +1275,7 @@ nomem_bulk: nomem_one: mas_set_alloc_req(mas, requested); if (mas->alloc && !(((unsigned long)mas->alloc & 0x1))) - mas->alloc->total = success; + mas->alloc->total = allocated; mas_set_err(mas, -ENOMEM); return; @@ -5725,6 +5724,7 @@ int mas_preallocate(struct ma_state *mas void mas_destroy(struct ma_state *mas) { struct maple_alloc *node; + unsigned long total; /* * When using mas_for_each() to insert an expected number of elements, @@ -5747,14 +5747,20 @@ void mas_destroy(struct ma_state *mas) } mas->mas_flags &= ~(MA_STATE_BULK|MA_STATE_PREALLOC); - while (mas->alloc && !((unsigned long)mas->alloc & 0x1)) { + total = mas_allocated(mas); + while (total) { node = mas->alloc; mas->alloc = node->slot[0]; - if (node->node_count > 0) - mt_free_bulk(node->node_count, - (void __rcu **)&node->slot[1]); + if (node->node_count > 1) { + size_t count = node->node_count - 1; + + mt_free_bulk(count, (void __rcu **)&node->slot[1]); + total -= count; + } kmem_cache_free(maple_node_cache, node); + total--; } + mas->alloc = NULL; } EXPORT_SYMBOL_GPL(mas_destroy); --- a/tools/testing/radix-tree/maple.c +++ b/tools/testing/radix-tree/maple.c @@ -173,11 +173,11 @@ static noinline void check_new_node(stru if (!MAPLE_32BIT) { if (i >= 35) - e = i - 35; + e = i - 34; else if (i >= 5) - e = i - 5; + e = i - 4; else if (i >= 2) - e = i - 2; + e = i - 1; } else { if (i >= 4) e = i - 4; @@ -305,17 +305,17 @@ static noinline void check_new_node(stru MT_BUG_ON(mt, mas.node != MA_ERROR(-ENOMEM)); MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL)); MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 1); - MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 1); + MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS); mn = mas_pop_node(&mas); /* get the next node. */ MT_BUG_ON(mt, mn == NULL); MT_BUG_ON(mt, not_empty(mn)); MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS); - MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 2); + MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 1); mas_push_node(&mas, mn); MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 1); - MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 1); + MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS); /* Check the limit of pop/push/pop */ mas_node_count(&mas, MAPLE_ALLOC_SLOTS + 2); /* Request */ @@ -323,14 +323,14 @@ static noinline void check_new_node(stru MT_BUG_ON(mt, mas.node != MA_ERROR(-ENOMEM)); MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL)); MT_BUG_ON(mt, mas_alloc_req(&mas)); - MT_BUG_ON(mt, mas.alloc->node_count); + MT_BUG_ON(mt, mas.alloc->node_count != 1); MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 2); mn = mas_pop_node(&mas); MT_BUG_ON(mt, not_empty(mn)); MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 1); - MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 1); + MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS); mas_push_node(&mas, mn); - MT_BUG_ON(mt, mas.alloc->node_count); + MT_BUG_ON(mt, mas.alloc->node_count != 1); MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 2); mn = mas_pop_node(&mas); MT_BUG_ON(mt, not_empty(mn));
