[8/8] mm/slub, percpu: correct the calculation of early percpu allocation size

  SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
during early boot. For that, the dynamic chunk of percpu which serves
the early allocation need be large enough to satisfy the kmalloc
creation.

However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
with correct calculation.

Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
 mm/slub.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
  

On Mon, Oct 24, 2022 at 04:14:35PM +0800, Baoquan He wrote:
> SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
> during early boot. For that, the dynamic chunk of percpu which serves
> the early allocation need be large enough to satisfy the kmalloc
> creation.
> 
> However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
> consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
> with correct calculation.
> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Pekka Enberg <penberg@kernel.org>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> ---
>  mm/slub.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 157527d7101b..8ac3bb9a122a 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4017,7 +4017,8 @@ init_kmem_cache_node(struct kmem_cache_node *n)
>  static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
>  {
>  	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
> -			KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
> +			NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
> +			sizeof(struct kmem_cache_cpu));
>  
>  	/*
>  	 * Must align to double word boundary for the double cmpxchg

Looks good to me.

Acked-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Thanks!

> -- 
> 2.34.1
>
  

On Mon, Oct 24, 2022 at 04:14:35PM +0800, Baoquan He wrote:
> SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
> during early boot. For that, the dynamic chunk of percpu which serves
> the early allocation need be large enough to satisfy the kmalloc
> creation.
> 
> However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
> consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
> with correct calculation.
> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Pekka Enberg <penberg@kernel.org>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> ---
>  mm/slub.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 157527d7101b..8ac3bb9a122a 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4017,7 +4017,8 @@ init_kmem_cache_node(struct kmem_cache_node *n)
>  static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
>  {
>  	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
> -			KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
> +			NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
> +			sizeof(struct kmem_cache_cpu));
>  
>  	/*
>  	 * Must align to double word boundary for the double cmpxchg
> -- 
> 2.34.1
> 

Acked-by: Dennis Zhou <dennis@kernel.org>

Thanks,
Dennis
  

On 10/24/22 10:14, Baoquan He wrote:
> SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
> during early boot. For that, the dynamic chunk of percpu which serves
> the early allocation need be large enough to satisfy the kmalloc
> creation.
> 
> However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
> consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
> with correct calculation.
> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Pekka Enberg <penberg@kernel.org>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> ---
>  mm/slub.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

As only slub is touched and there's no prerequsities in the previous
patches, I took this to the slab tree, branch
slab/for-6.2/cleanups

Thanks!

> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 157527d7101b..8ac3bb9a122a 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4017,7 +4017,8 @@ init_kmem_cache_node(struct kmem_cache_node *n)
>  static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
>  {
>  	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
> -			KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
> +			NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
> +			sizeof(struct kmem_cache_cpu));
>  
>  	/*
>  	 * Must align to double word boundary for the double cmpxchg
  

On 11/06/22 at 09:56pm, Vlastimil Babka wrote:
> On 10/24/22 10:14, Baoquan He wrote:
> > SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
> > during early boot. For that, the dynamic chunk of percpu which serves
> > the early allocation need be large enough to satisfy the kmalloc
> > creation.
> > 
> > However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
> > consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
> > with correct calculation.
> > 
> > Signed-off-by: Baoquan He <bhe@redhat.com>
> > Cc: Christoph Lameter <cl@linux.com>
> > Cc: Pekka Enberg <penberg@kernel.org>
> > Cc: David Rientjes <rientjes@google.com>
> > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Vlastimil Babka <vbabka@suse.cz>
> > Cc: Roman Gushchin <roman.gushchin@linux.dev>
> > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > ---
> >  mm/slub.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> As only slub is touched and there's no prerequsities in the previous
> patches, I took this to the slab tree, branch
> slab/for-6.2/cleanups

Yes, it only changes slub code. Thanks for taking it.

I will resend v2 with the left 7 percpu only patches with update.
  

Hi Baoquan,

On Mon, Nov 07, 2022 at 12:35:56PM +0800, Baoquan He wrote:
> On 11/06/22 at 09:56pm, Vlastimil Babka wrote:
> > On 10/24/22 10:14, Baoquan He wrote:
> > > SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
> > > during early boot. For that, the dynamic chunk of percpu which serves
> > > the early allocation need be large enough to satisfy the kmalloc
> > > creation.
> > > 
> > > However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
> > > consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
> > > with correct calculation.
> > > 
> > > Signed-off-by: Baoquan He <bhe@redhat.com>
> > > Cc: Christoph Lameter <cl@linux.com>
> > > Cc: Pekka Enberg <penberg@kernel.org>
> > > Cc: David Rientjes <rientjes@google.com>
> > > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > Cc: Vlastimil Babka <vbabka@suse.cz>
> > > Cc: Roman Gushchin <roman.gushchin@linux.dev>
> > > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > > ---
> > >  mm/slub.c | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > As only slub is touched and there's no prerequsities in the previous
> > patches, I took this to the slab tree, branch
> > slab/for-6.2/cleanups
> 
> Yes, it only changes slub code. Thanks for taking it.
> 
> I will resend v2 with the left 7 percpu only patches with update.
> 
> 

Don't worry about resending them, I'll pick them up tomorrow morning.

Thanks,
Dennis
  

On 11/06/22 at 11:20pm, Dennis Zhou wrote:
> Hi Baoquan,
> 
> On Mon, Nov 07, 2022 at 12:35:56PM +0800, Baoquan He wrote:
> > On 11/06/22 at 09:56pm, Vlastimil Babka wrote:
> > > On 10/24/22 10:14, Baoquan He wrote:
> > > > SLUB allocator relies on percpu allocator to initialize its ->cpu_slab
> > > > during early boot. For that, the dynamic chunk of percpu which serves
> > > > the early allocation need be large enough to satisfy the kmalloc
> > > > creation.
> > > > 
> > > > However, the current BUILD_BUG_ON() in alloc_kmem_cache_cpus() doesn't
> > > > consider the kmalloc array with NR_KMALLOC_TYPES length. Fix that
> > > > with correct calculation.
> > > > 
> > > > Signed-off-by: Baoquan He <bhe@redhat.com>
> > > > Cc: Christoph Lameter <cl@linux.com>
> > > > Cc: Pekka Enberg <penberg@kernel.org>
> > > > Cc: David Rientjes <rientjes@google.com>
> > > > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > > Cc: Vlastimil Babka <vbabka@suse.cz>
> > > > Cc: Roman Gushchin <roman.gushchin@linux.dev>
> > > > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > > > ---
> > > >  mm/slub.c | 3 ++-
> > > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > 
> > > As only slub is touched and there's no prerequsities in the previous
> > > patches, I took this to the slab tree, branch
> > > slab/for-6.2/cleanups
> > 
> > Yes, it only changes slub code. Thanks for taking it.
> > 
> > I will resend v2 with the left 7 percpu only patches with update.
> > 
> > 
> 
> Don't worry about resending them, I'll pick them up tomorrow morning.

That's great. Thanks a lot, Dennis.