On 05/07/2015 05:33 PM, Andrea Arcangeli wrote:
> On Thu, May 07, 2015 at 05:28:46PM +0300, Pavel Emelyanov wrote:
>> Yup, this is very close to what I did in my set -- introduced a message to
>> report back to the user-space on read. But my message is more than 8+2*1 bytes,
>> so we'll have one message for 0xAA API and another one for 0xAB (new) one :)
>
> I slightly altered it to fix an issue with packet alignments so it'd
> be 16bytes.
>
> How big is your msg currently? Could we get to use the same API?
Right now it's like this
struct uffd_event {
__u64 type;
union {
struct {
__u64 addr;
} pagefault;
struct {
__u32 ufd;
} fork;
struct {
__u64 from;
__u64 to;
__u64 len;
} remap;
} arg;
};
where .type is your uffd_msg.event and the rest is event-specific.
> UFFDIO_REGISTER_MODE_FORK
>
> or
>
> UFFDIO_REGISTER_MODE_NON_COOPERATIVE would differentiate if you want
> to register for fork/mremap/dontneed events as well or only the
> default (UFFD_EVENT_PAGEFAULT).
I planned to use this in UFFDIO_API call -- the uffdio_api.features will
be in-out argument denoting the bits user needs and reporting what kernel
can.
-- Pavel
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