Re: [PATCH] mm: Add vmalloc_user_node()

[Lorenzo Stoakes]

On Sun, Aug 20, 2023 at 08:40:31PM +0100, Matthew Wilcox (Oracle) wrote:
> Allow memory to be allocated on a specified node.  Use it in the
> perf ring-buffer code.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> I was looking at the perf ringbuffer code for other reasons, and I noticed
> that everything else gets allocated on the specified node ... except
> there's no way to do this for vmalloc.  I assume it'd be helpful here too.
>
>  include/linux/vmalloc.h     | 17 ++++++++++++++++-
>  kernel/events/ring_buffer.c |  2 +-
>  mm/vmalloc.c                |  9 +++++----
>  3 files changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index c720be70c8dd..030bfe1a60ab 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -6,6 +6,7 @@
>  #include <linux/init.h>
>  #include <linux/list.h>
>  #include <linux/llist.h>
> +#include <linux/numa.h>
>  #include <asm/page.h>		/* pgprot_t */
>  #include <linux/rbtree.h>
>  #include <linux/overflow.h>
> @@ -139,7 +140,7 @@ static inline unsigned long vmalloc_nr_pages(void) { return 0; }
>
>  extern void *vmalloc(unsigned long size) __alloc_size(1);
>  extern void *vzalloc(unsigned long size) __alloc_size(1);
> -extern void *vmalloc_user(unsigned long size) __alloc_size(1);
> +extern void *vmalloc_user_node(unsigned long size, int node) __alloc_size(1);
>  extern void *vmalloc_node(unsigned long size, int node) __alloc_size(1);
>  extern void *vzalloc_node(unsigned long size, int node) __alloc_size(1);
>  extern void *vmalloc_32(unsigned long size) __alloc_size(1);
> @@ -158,6 +159,20 @@ extern void *vmalloc_array(size_t n, size_t size) __alloc_size(1, 2);
>  extern void *__vcalloc(size_t n, size_t size, gfp_t flags) __alloc_size(1, 2);
>  extern void *vcalloc(size_t n, size_t size) __alloc_size(1, 2);
>
> +/**
> + * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
> + * @size: allocation size
> + *
> + * The resulting memory area is zeroed so it can be mapped to userspace
> + * without leaking data.
> + *
> + * Return: pointer to the allocated memory or %NULL on error
> + */
> +static inline void *vmalloc_user(size_t size)
> +{
> +	return vmalloc_user_node(size, NUMA_NO_NODE);
> +}
> +
>  extern void vfree(const void *addr);
>  extern void vfree_atomic(const void *addr);
>
> diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
> index cc90d5299005..c73add132618 100644
> --- a/kernel/events/ring_buffer.c
> +++ b/kernel/events/ring_buffer.c
> @@ -918,7 +918,7 @@ struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
>
>  	INIT_WORK(&rb->work, rb_free_work);
>
> -	all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
> +	all_buf = vmalloc_user_node((nr_pages + 1) * PAGE_SIZE, node);
>  	if (!all_buf)
>  		goto fail_all_buf;
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 228a4a5312f2..3616bfe4348f 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3461,22 +3461,23 @@ void *vzalloc(unsigned long size)
>  EXPORT_SYMBOL(vzalloc);
>
>  /**
> - * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
> + * vmalloc_user_node - allocate zeroed virtually contiguous memory for userspace
>   * @size: allocation size
> + * @node: NUMA node
>   *
>   * The resulting memory area is zeroed so it can be mapped to userspace
>   * without leaking data.
>   *
>   * Return: pointer to the allocated memory or %NULL on error
>   */
> -void *vmalloc_user(unsigned long size)
> +void *vmalloc_user_node(unsigned long size, int node)
>  {
>  	return __vmalloc_node_range(size, SHMLBA,  VMALLOC_START, VMALLOC_END,
>  				    GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL,
> -				    VM_USERMAP, NUMA_NO_NODE,
> +				    VM_USERMAP, node,
>  				    __builtin_return_address(0));
>  }
> -EXPORT_SYMBOL(vmalloc_user);
> +EXPORT_SYMBOL(vmalloc_user_node);
>
>  /**
>   * vmalloc_node - allocate memory on a specific node
> --
> 2.40.1
>

Reviewed-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>