From 9c01e9af171f13cf6573f404ecaf96dfa48233ab Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Wed, 10 Nov 2021 14:12:45 +0100 Subject: [PATCH] mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled The fields 'next' and 'slabs' are only used when CONFIG_SLUB_CPU_PARTIAL is enabled. We can put their definition to #ifdef to prevent accidental use when disabled. Currenlty show_slab_objects() and slabs_cpu_partial_show() contain code accessing the slabs field that's effectively dead with CONFIG_SLUB_CPU_PARTIAL=n through the wrappers slub_percpu_partial() and slub_percpu_partial_read_once(), but to prevent a compile error, we need to hide all this code behind #ifdef. Signed-off-by: Vlastimil Babka Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Roman Gushchin Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> --- mm/slab.h | 2 ++ mm/slub.c | 8 ++++++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/slab.h b/mm/slab.h index 495008f89bf6..f14e723b9e3c 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -25,10 +25,12 @@ struct slab { union { struct list_head slab_list; struct rcu_head rcu_head; +#ifdef CONFIG_SLUB_CPU_PARTIAL struct { struct slab *next; int slabs; /* Nr of slabs left */ }; +#endif }; struct kmem_cache *slab_cache; /* Double-word boundary */ diff --git a/mm/slub.c b/mm/slub.c index d08ba1025aae..261474092e43 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5258,6 +5258,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s, total += x; nodes[node] += x; +#ifdef CONFIG_SLUB_CPU_PARTIAL slab = slub_percpu_partial_read_once(c); if (slab) { node = slab_nid(slab); @@ -5270,6 +5271,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s, total += x; nodes[node] += x; } +#endif } } @@ -5469,9 +5471,10 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) { int objects = 0; int slabs = 0; - int cpu; + int cpu __maybe_unused; int len = 0; +#ifdef CONFIG_SLUB_CPU_PARTIAL for_each_online_cpu(cpu) { struct slab *slab; @@ -5480,12 +5483,13 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) if (slab) slabs += slab->slabs; } +#endif /* Approximate half-full slabs, see slub_set_cpu_partial() */ objects = (slabs * oo_objects(s->oo)) / 2; len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs); -#ifdef CONFIG_SMP +#if defined(CONFIG_SLUB_CPU_PARTIAL) && defined(CONFIG_SMP) for_each_online_cpu(cpu) { struct slab *slab; -- GitLab