| Message ID | 20220104001046.12263-30-vbabka@suse.cz (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Separate struct slab from struct page | expand |
On Tue, Jan 04, 2022 at 01:10:43AM +0100, Vlastimil Babka wrote: > 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 <vbabka@suse.cz> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > 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 362832f465e6..ac8be7dab535 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) CONFIG_SLUB_CPU_PARTIAL is defined like: config SLUB_CPU_PARTIAL default y depends on SLUB && SMP So I guess the " && defined(CONFIG_SMP)" part can be dropped. Otherwise lgtm. Reviewed-by: Roman Gushchin <guro@fb.com>
diff --git a/mm/slab.h b/mm/slab.h index 362832f465e6..ac8be7dab535 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;