From: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Date: Tue, 14 Feb 2023 09:51:12 +0800
> When we try to start AF_XDP on some machines with long running time, due
> to the machine's memory fragmentation problem, there is no sufficient
> contiguous physical memory that will cause the start failure.
[...]
> @@ -1319,13 +1317,10 @@ static int xsk_mmap(struct file *file, struct socket *sock,
>
> /* Matches the smp_wmb() in xsk_init_queue */
> smp_rmb();
> - qpg = virt_to_head_page(q->ring);
> - if (size > page_size(qpg))
> + if (size > PAGE_ALIGN(q->ring_size))
You can set q->ring_size as PAGE_ALIGN(size) already at the allocation
to simplify this. I don't see any other places where you use it.
> return -EINVAL;
>
> - pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;
> - return remap_pfn_range(vma, vma->vm_start, pfn,
> - size, vma->vm_page_prot);
> + return remap_vmalloc_range(vma, q->ring, 0);
> }
>
> static int xsk_notifier(struct notifier_block *this,
> diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c
> index 6cf9586e5027..247316bdfcbe 100644
> --- a/net/xdp/xsk_queue.c
> +++ b/net/xdp/xsk_queue.c
> @@ -7,6 +7,7 @@
> #include <linux/slab.h>
> #include <linux/overflow.h>
> #include <net/xdp_sock_drv.h>
> +#include <linux/vmalloc.h>
Alphabetic order maybe?
>
> #include "xsk_queue.h"
>
> @@ -23,7 +24,6 @@ static size_t xskq_get_ring_size(struct xsk_queue *q, bool umem_queue)
> struct xsk_queue *xskq_create(u32 nentries, bool umem_queue)
> {
> struct xsk_queue *q;
> - gfp_t gfp_flags;
> size_t size;
>
> q = kzalloc(sizeof(*q), GFP_KERNEL);
> @@ -33,12 +33,10 @@ struct xsk_queue *xskq_create(u32 nentries, bool umem_queue)
> q->nentries = nentries;
> q->ring_mask = nentries - 1;
>
> - gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN |
> - __GFP_COMP | __GFP_NORETRY;
> size = xskq_get_ring_size(q, umem_queue);
>
> - q->ring = (struct xdp_ring *)__get_free_pages(gfp_flags,
> - get_order(size));
> + q->ring_size = size;
Maybe assign size only after successful allocation?
> + q->ring = (struct xdp_ring *)vmalloc_user(size);
The cast from `void *` is redundant. It was needed for
__get_free_pages() since it returns pointer as long.
> if (!q->ring) {
> kfree(q);
> return NULL;
> @@ -52,6 +50,6 @@ void xskq_destroy(struct xsk_queue *q)
> if (!q)
> return;
>
> - page_frag_free(q->ring);
> + vfree(q->ring);
> kfree(q);
> }
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index c6fb6b763658..35922b8b92a8 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -45,6 +45,7 @@ struct xsk_queue {
> struct xdp_ring *ring;
> u64 invalid_descs;
> u64 queue_empty_descs;
> + size_t ring_size;
> };
>
> /* The structure of the shared state of the rings are a simple
Thanks,
Olek
