> UVMPAGER_ASYNCIO_START is used in
> genfs_getpages() to indicate the start of an async i/o transaction.

let me cite my original question:

> > +/* Flags to uvm_io_done */
> > +#define UVMPAGER_SYNCIO_DONE       0x01    /* Synch i/o has completed */
> > +#define UVMPAGER_ASYNCIO_START     0x02    /* Asynch i/o started */
> > +#define UVMPAGER_ASYNCIO_DONE      0x03    /* Asynch i/o has completed */
> > +
>
> can you explain "Asynch i/o started"?
> to me, it seems to be used only when async getpages found all pages cached.
> ie. no i/o is started.

in particular, i don't understand which i/o you are talking about.

YAMAMOTO Takashi