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Re: [Qemu-devel] [PATCH v3 16/46] ivshmem: remove max_peer field
From: |
Claudio Fontana |
Subject: |
Re: [Qemu-devel] [PATCH v3 16/46] ivshmem: remove max_peer field |
Date: |
Wed, 16 Sep 2015 11:39:02 +0200 |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 |
On 15.09.2015 18:07, address@hidden wrote:
> From: Marc-André Lureau <address@hidden>
>
> max_peer isn't really useful, it tracks the maximum received VM id, but
> that quickly matches nb_peers, the size of the peers array. Since VM
> come and go, there might be sparse peers so it doesn't help much in
> general to have this value around.
Does this max_peer provide any value if VMs _don't_ come and go?
Not that I see any.
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
> hw/misc/ivshmem.c | 10 +---------
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index 07f2182..cda7dce 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -90,7 +90,6 @@ typedef struct IVShmemState {
>
> Peer *peers;
> int nb_peers; /* how many guests we have space for */
> - int max_peer; /* maximum numbered peer */
>
> int vm_id;
> uint32_t vectors;
> @@ -200,7 +199,7 @@ static void ivshmem_io_write(void *opaque, hwaddr addr,
>
> case DOORBELL:
> /* check that dest VM ID is reasonable */
> - if (dest > s->max_peer) {
> + if (dest >= s->nb_peers) {
> IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
> break;
> }
> @@ -574,11 +573,6 @@ static void ivshmem_read(void *opaque, const uint8_t
> *buf, int size)
> /* increment count for particular guest */
> s->peers[incoming_posn].nb_eventfds++;
>
> - /* keep track of the maximum VM ID */
> - if (incoming_posn > s->max_peer) {
> - s->max_peer = incoming_posn;
> - }
> -
> if (incoming_posn == s->vm_id) {
> s->eventfd_chr[guest_max_eventfd] = create_eventfd_chr_device(s,
> &s->peers[s->vm_id].eventfds[guest_max_eventfd],
> @@ -721,8 +715,6 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error
> **errp)
> PCI_BASE_ADDRESS_MEM_PREFETCH;;
> Error *local_err = NULL;
>
> - s->max_peer = -1;
> -
> if (s->sizearg == NULL) {
> s->ivshmem_size = 4 << 20; /* 4 MB default */
> } else {
>
- [Qemu-devel] [PATCH v3 11/46] ivshmem: limit maximum number of peers to G_MAXUINT16, (continued)
- [Qemu-devel] [PATCH v3 11/46] ivshmem: limit maximum number of peers to G_MAXUINT16, marcandre . lureau, 2015/09/15
- [Qemu-devel] [PATCH v3 12/46] ivshmem: simplify around increase_dynamic_storage(), marcandre . lureau, 2015/09/15
- [Qemu-devel] [PATCH v3 13/46] ivshmem: allocate eventfds in resize_peers(), marcandre . lureau, 2015/09/15
- [Qemu-devel] [PATCH v3 14/46] ivshmem: remove useless ivshmem_update_irq() val argument, marcandre . lureau, 2015/09/15
- [Qemu-devel] [PATCH v3 15/46] ivshmem: initialize max_peer to -1, marcandre . lureau, 2015/09/15
- [Qemu-devel] [PATCH v3 16/46] ivshmem: remove max_peer field, marcandre . lureau, 2015/09/15
- Re: [Qemu-devel] [PATCH v3 16/46] ivshmem: remove max_peer field,
Claudio Fontana <=
- [Qemu-devel] [PATCH v3 18/46] ivshmem: improve error, marcandre . lureau, 2015/09/15
- [Qemu-devel] [PATCH v3 17/46] ivshmem: improve debug messages, marcandre . lureau, 2015/09/15
[Qemu-devel] [PATCH v3 20/46] ivshmem: simplify a bit the code, marcandre . lureau, 2015/09/15