On Tue, 14 Feb 2023 15:45:12 +0100, Alexander Lobakin <alexandr.lobakin@xxxxxxxxx> wrote:
> 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.
That's it, but I think it is not particularly appropriate to change the
the semantics of ring_size just for simplify this code. This may make
people feel strange.
I agree with you other opinions.
Thanks.
>
> > 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
