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From: Paolo Bonzini <pbonzini@redhat.com>
To: Rusty Russell <rusty@rustcorp.com.au>, netdev <netdev@vger.kernel.org>
Cc: virtualization@lists.linux-foundation.org,
	Andy Lutomirski <luto@amacapital.net>,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 3/3] virtio_ring: unify direct/indirect code paths.
Date: Fri, 05 Sep 2014 12:55:37 +0200	[thread overview]
Message-ID: <540996A9.4060100@redhat.com> (raw)
In-Reply-To: <1409718556-3041-4-git-send-email-rusty@rustcorp.com.au>

Il 03/09/2014 06:29, Rusty Russell ha scritto:
> + 	desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp);
> + 	if (!desc)
> +		return NULL;
>  
> -	return head;
> +	for (i = 0; i < total_sg; i++)
> +		desc[i].next = i+1;
> +	return desc;
>  }

Would it make sense to keep a cache of a few (say) 8- or 16-element
indirect descriptors?  You'd only have to do this ugly (and slowish) for
loop on the first allocation.

Also, since this is mostly an aesthetic patch,

> +	if (indirect)
> +		vq->free_head = vq->vring.desc[head].next;
> +	else
> +		vq->free_head = i;

I'd move the indirect case above, where the vring.desc[head] is actually
allocated.

Paolo

  parent reply	other threads:[~2014-09-05 10:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-03  4:29 [PATCH 0/3] virtio: simplify virtio_ring Rusty Russell
2014-09-03  4:29 ` [PATCH 1/3] virtio_net: pass well-formed sgs to virtqueue_add_*() Rusty Russell
2014-09-03  4:54   ` Andy Lutomirski
2014-09-03 10:23   ` Jesper Dangaard Brouer
2014-09-03  4:29 ` [PATCH 2/3] virtio_ring: assume sgs are always well-formed Rusty Russell
2014-09-03  4:29 ` [PATCH 3/3] virtio_ring: unify direct/indirect code paths Rusty Russell
2014-09-04  1:59   ` Andy Lutomirski
2014-09-05  2:55     ` Rusty Russell
2014-09-05 10:55   ` Paolo Bonzini [this message]
2014-09-08 17:32     ` Andy Lutomirski
     [not found] ` <1409718556-3041-2-git-send-email-rusty__16380.2289790057$1409718628$gmane$org@rustcorp.com.au>
2014-09-05 10:40   ` [PATCH 1/3] virtio_net: pass well-formed sgs to virtqueue_add_*() Paolo Bonzini
2014-09-07  7:20     ` Michael S. Tsirkin
2014-10-14  2:21       ` Rusty Russell
2014-09-05 21:27 ` [PATCH 0/3] virtio: simplify virtio_ring David Miller
     [not found] <1410396458-1165-1-git-send-email-rusty@rustcorp.com.au>
2014-09-11  0:47 ` [PATCH 3/3] virtio_ring: unify direct/indirect code paths Rusty Russell

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