A number of stat items related to cpu slabs became unused, remove them. Two of those were ALLOC_FASTPATH and FREE_FASTPATH. But instead of removing those, use them instead of ALLOC_PCS and FREE_PCS, since sheaves are the new (and only) fastpaths, Remove the recently added _PCS variants instead. Change where FREE_SLOWPATH is counted so that it only counts freeing of objects by slab users that (for whatever reason) do not go to a percpu sheaf, and not all (including internal) callers of __slab_free(). Thus flushing sheaves (counted by SHEAF_FLUSH) no longer also increments FREE_SLOWPATH. This matches how ALLOC_SLOWPATH doesn't count sheaf refills (counted by SHEAF_REFILL). Reviewed-by: Suren Baghdasaryan Signed-off-by: Vlastimil Babka --- mm/slub.c | 77 +++++++++++++++++---------------------------------------------- 1 file changed, 21 insertions(+), 56 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index c12e90cb2fca..d73ad44fa046 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -330,33 +330,19 @@ enum add_mode { }; enum stat_item { - ALLOC_PCS, /* Allocation from percpu sheaf */ - ALLOC_FASTPATH, /* Allocation from cpu slab */ - ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */ - FREE_PCS, /* Free to percpu sheaf */ + ALLOC_FASTPATH, /* Allocation from percpu sheaves */ + ALLOC_SLOWPATH, /* Allocation from partial or new slab */ FREE_RCU_SHEAF, /* Free to rcu_free sheaf */ FREE_RCU_SHEAF_FAIL, /* Failed to free to a rcu_free sheaf */ - FREE_FASTPATH, /* Free to cpu slab */ - FREE_SLOWPATH, /* Freeing not to cpu slab */ + FREE_FASTPATH, /* Free to percpu sheaves */ + FREE_SLOWPATH, /* Free to a slab */ FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */ FREE_REMOVE_PARTIAL, /* Freeing removes last object */ - ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */ - ALLOC_SLAB, /* Cpu slab acquired from page allocator */ - ALLOC_REFILL, /* Refill cpu slab from slab freelist */ - ALLOC_NODE_MISMATCH, /* Switching cpu slab */ + ALLOC_SLAB, /* New slab acquired from page allocator */ + ALLOC_NODE_MISMATCH, /* Requested node different from cpu sheaf */ FREE_SLAB, /* Slab freed to the page allocator */ - CPUSLAB_FLUSH, /* Abandoning of the cpu slab */ - DEACTIVATE_FULL, /* Cpu slab was full when deactivated */ - DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */ - DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */ - DEACTIVATE_BYPASS, /* Implicit deactivation */ ORDER_FALLBACK, /* Number of times fallback was necessary */ - CMPXCHG_DOUBLE_CPU_FAIL,/* Failures of this_cpu_cmpxchg_double */ CMPXCHG_DOUBLE_FAIL, /* Failures of slab freelist update */ - CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */ - CPU_PARTIAL_FREE, /* Refill cpu partial on free */ - CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */ - CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */ SHEAF_FLUSH, /* Objects flushed from a sheaf */ SHEAF_REFILL, /* Objects refilled to a sheaf */ SHEAF_ALLOC, /* Allocation of an empty sheaf */ @@ -4347,8 +4333,10 @@ void *alloc_from_pcs(struct kmem_cache *s, gfp_t gfp, int node) * We assume the percpu sheaves contain only local objects although it's * not completely guaranteed, so we verify later. */ - if (unlikely(node_requested && node != numa_mem_id())) + if (unlikely(node_requested && node != numa_mem_id())) { + stat(s, ALLOC_NODE_MISMATCH); return NULL; + } if (!local_trylock(&s->cpu_sheaves->lock)) return NULL; @@ -4371,6 +4359,7 @@ void *alloc_from_pcs(struct kmem_cache *s, gfp_t gfp, int node) */ if (page_to_nid(virt_to_page(object)) != node) { local_unlock(&s->cpu_sheaves->lock); + stat(s, ALLOC_NODE_MISMATCH); return NULL; } } @@ -4379,7 +4368,7 @@ void *alloc_from_pcs(struct kmem_cache *s, gfp_t gfp, int node) local_unlock(&s->cpu_sheaves->lock); - stat(s, ALLOC_PCS); + stat(s, ALLOC_FASTPATH); return object; } @@ -4451,7 +4440,7 @@ unsigned int alloc_from_pcs_bulk(struct kmem_cache *s, gfp_t gfp, size_t size, local_unlock(&s->cpu_sheaves->lock); - stat_add(s, ALLOC_PCS, batch); + stat_add(s, ALLOC_FASTPATH, batch); allocated += batch; @@ -5111,8 +5100,6 @@ static void __slab_free(struct kmem_cache *s, struct slab *slab, unsigned long flags; bool on_node_partial; - stat(s, FREE_SLOWPATH); - if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) { free_to_partial_list(s, slab, head, tail, cnt, addr); return; @@ -5416,7 +5403,7 @@ bool free_to_pcs(struct kmem_cache *s, void *object, bool allow_spin) local_unlock(&s->cpu_sheaves->lock); - stat(s, FREE_PCS); + stat(s, FREE_FASTPATH); return true; } @@ -5664,7 +5651,7 @@ static void free_to_pcs_bulk(struct kmem_cache *s, size_t size, void **p) local_unlock(&s->cpu_sheaves->lock); - stat_add(s, FREE_PCS, batch); + stat_add(s, FREE_FASTPATH, batch); if (batch < size) { p += batch; @@ -5686,10 +5673,12 @@ static void free_to_pcs_bulk(struct kmem_cache *s, size_t size, void **p) */ fallback: __kmem_cache_free_bulk(s, size, p); + stat_add(s, FREE_SLOWPATH, size); flush_remote: if (remote_nr) { __kmem_cache_free_bulk(s, remote_nr, &remote_objects[0]); + stat_add(s, FREE_SLOWPATH, remote_nr); if (i < size) { remote_nr = 0; goto next_remote_batch; @@ -5784,6 +5773,7 @@ void slab_free(struct kmem_cache *s, struct slab *slab, void *object, } __slab_free(s, slab, object, object, 1, addr); + stat(s, FREE_SLOWPATH); } #ifdef CONFIG_MEMCG @@ -5806,8 +5796,10 @@ void slab_free_bulk(struct kmem_cache *s, struct slab *slab, void *head, * With KASAN enabled slab_free_freelist_hook modifies the freelist * to remove objects, whose reuse must be delayed. */ - if (likely(slab_free_freelist_hook(s, &head, &tail, &cnt))) + if (likely(slab_free_freelist_hook(s, &head, &tail, &cnt))) { __slab_free(s, slab, head, tail, cnt, addr); + stat_add(s, FREE_SLOWPATH, cnt); + } } #ifdef CONFIG_SLUB_RCU_DEBUG @@ -6705,6 +6697,7 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, i = refill_objects(s, p, flags, size, size); if (i < size) goto error; + stat_add(s, ALLOC_SLOWPATH, i); } return i; @@ -8704,33 +8697,19 @@ static ssize_t text##_store(struct kmem_cache *s, \ } \ SLAB_ATTR(text); \ -STAT_ATTR(ALLOC_PCS, alloc_cpu_sheaf); STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath); STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath); -STAT_ATTR(FREE_PCS, free_cpu_sheaf); STAT_ATTR(FREE_RCU_SHEAF, free_rcu_sheaf); STAT_ATTR(FREE_RCU_SHEAF_FAIL, free_rcu_sheaf_fail); STAT_ATTR(FREE_FASTPATH, free_fastpath); STAT_ATTR(FREE_SLOWPATH, free_slowpath); STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial); STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial); -STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial); STAT_ATTR(ALLOC_SLAB, alloc_slab); -STAT_ATTR(ALLOC_REFILL, alloc_refill); STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch); STAT_ATTR(FREE_SLAB, free_slab); -STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush); -STAT_ATTR(DEACTIVATE_FULL, deactivate_full); -STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty); -STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees); -STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass); STAT_ATTR(ORDER_FALLBACK, order_fallback); -STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail); STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail); -STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc); -STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free); -STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node); -STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain); STAT_ATTR(SHEAF_FLUSH, sheaf_flush); STAT_ATTR(SHEAF_REFILL, sheaf_refill); STAT_ATTR(SHEAF_ALLOC, sheaf_alloc); @@ -8806,33 +8785,19 @@ static struct attribute *slab_attrs[] = { &remote_node_defrag_ratio_attr.attr, #endif #ifdef CONFIG_SLUB_STATS - &alloc_cpu_sheaf_attr.attr, &alloc_fastpath_attr.attr, &alloc_slowpath_attr.attr, - &free_cpu_sheaf_attr.attr, &free_rcu_sheaf_attr.attr, &free_rcu_sheaf_fail_attr.attr, &free_fastpath_attr.attr, &free_slowpath_attr.attr, &free_add_partial_attr.attr, &free_remove_partial_attr.attr, - &alloc_from_partial_attr.attr, &alloc_slab_attr.attr, - &alloc_refill_attr.attr, &alloc_node_mismatch_attr.attr, &free_slab_attr.attr, - &cpuslab_flush_attr.attr, - &deactivate_full_attr.attr, - &deactivate_empty_attr.attr, - &deactivate_remote_frees_attr.attr, - &deactivate_bypass_attr.attr, &order_fallback_attr.attr, &cmpxchg_double_fail_attr.attr, - &cmpxchg_double_cpu_fail_attr.attr, - &cpu_partial_alloc_attr.attr, - &cpu_partial_free_attr.attr, - &cpu_partial_node_attr.attr, - &cpu_partial_drain_attr.attr, &sheaf_flush_attr.attr, &sheaf_refill_attr.attr, &sheaf_alloc_attr.attr, -- 2.52.0