[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v10] xen: add para-virtual sound interface header file
Hi, On 24/11/16 17:11, Oleksandr Andrushchenko wrote: +struct xensnd_close_req { +};I'm afraid structures without any members aren't permitted by C89.There are 2 options I see: 1. Remove empty structures 2. Leave them in, but add a comment and add a dummy place holder I would prefer option 1 as this way the interface seems to be clearer, like all requests are defined etc.+struct xensnd_request { + uint8_t raw[64]; +}; + +struct xensnd_response { + uint8_t raw[64]; +};What are these two needed for now? If you want to enforce a minimum size, that would better go ...That is because we want to be cache line aligned. But this is only accurate to your platform. There is HW available with 128 bytes. For instance on Xen ARM, all the structures are aligned to 128 bytes in order to fit in most of cache line. Although technically it would be possible have bigger one (see the definition of CSSIDR). What it means in practice is not clear as we have so many HW around, so it is not possible to fit all. So the options could be: 1. 32 or 64 2. 48 I think is not an option here Why 48? Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |