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Date: Thu, 21 Mar 2013 10:25:12 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC 10/12] Add qemu_put_buffer_no_copy
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To: Orit Wasserman <owasserm@redhat.com>
Cc: mst@redhat.com, chegu_vinod@hp.com, qemu-devel@nongnu.org, quintela@redhat.com

Il 21/03/2013 10:09, Orit Wasserman ha scritto:
> +    f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
> +    f->iov[f->iovcnt++].iov_len = size;
> +
> +    f->is_write = 1;
> +    f->bytes_xfer += size;
> +
> +    if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
> +        qemu_fflush(f);
>      }

It should not be complex to check if f->iov[f->iovcnt - 1] can be
extended?  This could remove many system calls when you have many
consecutive zero pages.

Paolo