Subject: Re: [PATCH RFC 2/4] mm: percpu: Add pcpu_fc_cpu_to_node_fn_t typedef

From: Dennis Zhou <[email-masked]>
Date: Mon, 29 Nov 2021 17:40:49 -0500

On Sun, Nov 21, 2021 at 05:35:55PM +0800, Kefeng Wang wrote:
> Add pcpu_fc_cpu_to_node_fn_t and pass it into pcpu_fc_alloc_fn_t,
> pcpu first chunk allocation will call it to alloc memblock on the
> corresponding node by it.
> 
> Signed-off-by: Kefeng Wang <[email-masked]>
> ---
>  arch/mips/mm/init.c            | 12 +++++++++---
>  arch/powerpc/kernel/setup_64.c | 14 +++++++++++---
>  arch/sparc/kernel/smp_64.c     |  8 +++++---
>  arch/x86/kernel/setup_percpu.c | 18 +++++++++++++-----
>  drivers/base/arch_numa.c       |  8 +++++---
>  include/linux/percpu.h         |  7 +++++--
>  mm/percpu.c                    | 14 +++++++++-----
>  7 files changed, 57 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
> index 325e1552cbea..ebbf6923532c 100644
> --- a/arch/mips/mm/init.c
> +++ b/arch/mips/mm/init.c
> @@ -519,12 +519,17 @@ static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
>  	return node_distance(cpu_to_node(from), cpu_to_node(to));
>  }
>  
> -static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size,
> -				       size_t align)
> +static int __init pcpu_cpu_to_node(int cpu)
> +{
> +	return cpu_to_node(cpu);
> +}
> +
> +static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align,
> +				   pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
>  	return memblock_alloc_try_nid(size, align, __pa(MAX_DMA_ADDRESS),
>  				      MEMBLOCK_ALLOC_ACCESSIBLE,
> -				      cpu_to_node(cpu));
> +				      cpu_to_nd_fun(cpu));
>  }
>  
>  static void __init pcpu_fc_free(void *ptr, size_t size)
> @@ -545,6 +550,7 @@ void __init setup_per_cpu_areas(void)
>  	rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
>  				    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
>  				    pcpu_cpu_distance,
> +				    pcpu_cpu_to_node,
>  				    pcpu_fc_alloc, pcpu_fc_free);
>  	if (rc < 0)
>  		panic("Failed to initialize percpu areas.");
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 6052f5d5ded3..9a5609c821df 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -771,6 +771,12 @@ void __init emergency_stack_init(void)
>  }
>  
>  #ifdef CONFIG_SMP
> +
> +static __init int pcpu_cpu_to_node(int cpu)
> +{
> +	return IS_ENABLED(CONFIG_NUMA) ? early_cpu_to_node(cpu) : NUMA_NO_NODE;
> +}
> +
>  /**
>   * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
>   * @cpu: cpu to allocate for
> @@ -784,12 +790,12 @@ void __init emergency_stack_init(void)
>   * RETURNS:
>   * Pointer to the allocated area on success, NULL on failure.
>   */
> -static void * __init pcpu_alloc_bootmem(unsigned int cpu, size_t size,
> -					size_t align)
> +static void * __init pcpu_alloc_bootmem(unsigned int cpu, size_t size, size_t align,
> +					pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
>  	const unsigned long goal = __pa(MAX_DMA_ADDRESS);
>  #ifdef CONFIG_NUMA
> -	int node = early_cpu_to_node(cpu);
> +	int node = cpu_to_nd_fun(cpu);

^ typo - cpu_to_nd_fn().

>  	void *ptr;
>  
>  	if (!node_online(node) || !NODE_DATA(node)) {
> @@ -891,6 +897,7 @@ void __init setup_per_cpu_areas(void)
>  
>  	if (pcpu_chosen_fc != PCPU_FC_PAGE) {
>  		rc = pcpu_embed_first_chunk(0, dyn_size, atom_size, pcpu_cpu_distance,
> +					    pcpu_cpu_to_node,
>  					    pcpu_alloc_bootmem, pcpu_free_bootmem);
>  		if (rc)
>  			pr_warn("PERCPU: %s allocator failed (%d), "
> @@ -900,6 +907,7 @@ void __init setup_per_cpu_areas(void)
>  
>  	if (rc < 0)
>  		rc = pcpu_page_first_chunk(0, pcpu_alloc_bootmem, pcpu_free_bootmem,
> +					   pcpu_cpu_to_node,
>  					   pcpu_populate_pte);
>  	if (rc < 0)
>  		panic("cannot initialize percpu area (err=%d)", rc);
> diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
> index b98a7bbe6728..026aa3ccbc30 100644
> --- a/arch/sparc/kernel/smp_64.c
> +++ b/arch/sparc/kernel/smp_64.c
> @@ -1539,12 +1539,12 @@ void smp_send_stop(void)
>   * RETURNS:
>   * Pointer to the allocated area on success, NULL on failure.
>   */
> -static void * __init pcpu_alloc_bootmem(unsigned int cpu, size_t size,
> -					size_t align)
> +static void * __init pcpu_alloc_bootmem(unsigned int cpu, size_t size, size_t align,
> +					pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
>  	const unsigned long goal = __pa(MAX_DMA_ADDRESS);
>  #ifdef CONFIG_NUMA
> -	int node = cpu_to_node(cpu);
> +	int node = cpu_to_nd_fn(cpu);
>  	void *ptr;
>  
>  	if (!node_online(node) || !NODE_DATA(node)) {
> @@ -1641,6 +1641,7 @@ void __init setup_per_cpu_areas(void)
>  		rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
>  					    PERCPU_DYNAMIC_RESERVE, 4 << 20,
>  					    pcpu_cpu_distance,
> +					    cpu_to_node,
>  					    pcpu_alloc_bootmem,
>  					    pcpu_free_bootmem);
>  		if (rc)
> @@ -1652,6 +1653,7 @@ void __init setup_per_cpu_areas(void)
>  		rc = pcpu_page_first_chunk(PERCPU_MODULE_RESERVE,
>  					   pcpu_alloc_bootmem,
>  					   pcpu_free_bootmem,
> +					   cpu_to_node,
>  					   pcpu_populate_pte);
>  	if (rc < 0)
>  		panic("cannot initialize percpu area (err=%d)", rc);
> diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
> index 7b65275544b2..bba4fa174a16 100644
> --- a/arch/x86/kernel/setup_percpu.c
> +++ b/arch/x86/kernel/setup_percpu.c
> @@ -97,12 +97,12 @@ static bool __init pcpu_need_numa(void)
>   * RETURNS:
>   * Pointer to the allocated area on success, NULL on failure.
>   */
> -static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
> -					unsigned long align)
> +static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size, unsigned long align,
> +					pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
>  	const unsigned long goal = __pa(MAX_DMA_ADDRESS);
>  #ifdef CONFIG_NUMA
> -	int node = early_cpu_to_node(cpu);
> +	int node = cpu_to_nd_fn(cpu);
>  	void *ptr;
>  
>  	if (!node_online(node) || !NODE_DATA(node)) {
> @@ -128,9 +128,10 @@ static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
>  /*
>   * Helpers for first chunk memory allocation
>   */
> -static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
> +static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align,
> +				   pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
> -	return pcpu_alloc_bootmem(cpu, size, align);
> +	return pcpu_alloc_bootmem(cpu, size, align, cpu_to_nd_fn);
>  }
>  
>  static void __init pcpu_fc_free(void *ptr, size_t size)
> @@ -150,6 +151,11 @@ static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
>  #endif
>  }
>  
> +static int __init pcpu_cpu_to_node(int cpu)
> +{
> +	return IS_ENABLED(CONFIG_NUMA) ? early_cpu_to_node(cpu) : NUMA_NO_NODE;
> +}
> +
>  static void __init pcpup_populate_pte(unsigned long addr)
>  {
>  	populate_extra_pte(addr);
> @@ -205,6 +211,7 @@ void __init setup_per_cpu_areas(void)
>  		rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
>  					    dyn_size, atom_size,
>  					    pcpu_cpu_distance,
> +					    pcpu_cpu_to_node,
>  					    pcpu_fc_alloc, pcpu_fc_free);
>  		if (rc < 0)
>  			pr_warn("%s allocator failed (%d), falling back to page size\n",
> @@ -213,6 +220,7 @@ void __init setup_per_cpu_areas(void)
>  	if (rc < 0)
>  		rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
>  					   pcpu_fc_alloc, pcpu_fc_free,
> +					   pcpu_cpu_to_node,
>  					   pcpup_populate_pte);
>  	if (rc < 0)
>  		panic("cannot initialize percpu area (err=%d)", rc);
> diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
> index bc1876915457..273543d9ff85 100644
> --- a/drivers/base/arch_numa.c
> +++ b/drivers/base/arch_numa.c
> @@ -155,10 +155,10 @@ static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
>  	return node_distance(early_cpu_to_node(from), early_cpu_to_node(to));
>  }
>  
> -static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size,
> -				       size_t align)
> +static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align,
> +				   pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
> -	int nid = early_cpu_to_node(cpu);
> +	int nid = cpu_to_nd_fn(cpu);
>  
>  	return  memblock_alloc_try_nid(size, align,
>  			__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid);
> @@ -229,6 +229,7 @@ void __init setup_per_cpu_areas(void)
>  		rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
>  					    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
>  					    pcpu_cpu_distance,
> +					    early_cpu_to_node,
>  					    pcpu_fc_alloc, pcpu_fc_free);
>  #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
>  		if (rc < 0)
> @@ -242,6 +243,7 @@ void __init setup_per_cpu_areas(void)
>  		rc = pcpu_page_first_chunk(PERCPU_MODULE_RESERVE,
>  					   pcpu_fc_alloc,
>  					   pcpu_fc_free,
> +					   early_cpu_to_node,
>  					   pcpu_populate_pte);
>  #endif
>  	if (rc < 0)
> diff --git a/include/linux/percpu.h b/include/linux/percpu.h
> index ae4004e7957e..41bb54715b0c 100644
> --- a/include/linux/percpu.h
> +++ b/include/linux/percpu.h
> @@ -94,8 +94,9 @@ extern const char * const pcpu_fc_names[PCPU_FC_NR];
>  
>  extern enum pcpu_fc pcpu_chosen_fc;
>  
> -typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
> -				     size_t align);
> +typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
> +typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size, size_t align,
> +				     pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
>  typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
>  typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
>  typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
> @@ -111,6 +112,7 @@ extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
>  extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
>  				size_t atom_size,
>  				pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
> +				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn,
>  				pcpu_fc_alloc_fn_t alloc_fn,
>  				pcpu_fc_free_fn_t free_fn);
>  #endif
> @@ -119,6 +121,7 @@ extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
>  extern int __init pcpu_page_first_chunk(size_t reserved_size,
>  				pcpu_fc_alloc_fn_t alloc_fn,
>  				pcpu_fc_free_fn_t free_fn,
> +				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn,
>  				pcpu_fc_populate_pte_fn_t populate_pte_fn);
>  #endif

Be consistent here. In pcpu_setup_first_chunk() you add the
cpu_to_node() before alloc()/free() and then in pcpu_embed_first_chunk()
you add it after. I'd prefer to add it before as to keep the
cpu_distance()/cpu_to_node() grouping.

>  
> diff --git a/mm/percpu.c b/mm/percpu.c
> index f5b2c2ea5a54..3f6cf1ff0be2 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -3001,6 +3001,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
>   * @dyn_size: minimum free size for dynamic allocation in bytes
>   * @atom_size: allocation atom size
>   * @cpu_distance_fn: callback to determine distance between cpus, optional
> + * @cpu_to_nd_fn: callback to convert cpu to it's node, optional
>   * @alloc_fn: function to allocate percpu page
>   * @free_fn: function to free percpu page
>   *
> @@ -3030,6 +3031,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
>  int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
>  				  size_t atom_size,
>  				  pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
> +				  pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn,
>  				  pcpu_fc_alloc_fn_t alloc_fn,
>  				  pcpu_fc_free_fn_t free_fn)
>  {
> @@ -3066,7 +3068,7 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
>  		BUG_ON(cpu == NR_CPUS);
>  
>  		/* allocate space for the whole group */
> -		ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
> +		ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size, cpu_to_nd_fn);
>  		if (!ptr) {
>  			rc = -ENOMEM;
>  			goto out_free_areas;
> @@ -3145,6 +3147,7 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
>   * @reserved_size: the size of reserved percpu area in bytes
>   * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
>   * @free_fn: function to free percpu page, always called with PAGE_SIZE
> + * @cpu_to_nd_fn: callback to convert cpu to it's node, optional
>   * @populate_pte_fn: function to populate pte
>   *
>   * This is a helper to ease setting up page-remapped first percpu
> @@ -3159,6 +3162,7 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
>  int __init pcpu_page_first_chunk(size_t reserved_size,
>  				 pcpu_fc_alloc_fn_t alloc_fn,
>  				 pcpu_fc_free_fn_t free_fn,
> +				 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn,
>  				 pcpu_fc_populate_pte_fn_t populate_pte_fn)
>  {
>  	static struct vm_struct vm;
> @@ -3201,7 +3205,7 @@ int __init pcpu_page_first_chunk(size_t reserved_size,
>  		for (i = 0; i < unit_pages; i++) {
>  			void *ptr;
>  
> -			ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
> +			ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE, cpu_to_nd_fn);
>  			if (!ptr) {
>  				pr_warn("failed to allocate %s page for cpu%u\n",
>  						psize_str, cpu);
> @@ -3278,8 +3282,8 @@ int __init pcpu_page_first_chunk(size_t reserved_size,
>  unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
>  EXPORT_SYMBOL(__per_cpu_offset);
>  
> -static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
> -				       size_t align)
> +static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size, size_t align,
> +				       pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
>  {
>  	return  memblock_alloc_from(size, align, __pa(MAX_DMA_ADDRESS));
>  }
> @@ -3300,7 +3304,7 @@ void __init setup_per_cpu_areas(void)
>  	 * what the legacy allocator did.
>  	 */
>  	rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
> -				    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
> +				    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL, NULL,
>  				    pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
>  	if (rc < 0)
>  		panic("Failed to initialize percpu areas.");
> -- 
> 2.26.2
> 

Thanks,
Dennis