diff options
Diffstat (limited to 'share/man/man9/physio.9')
-rw-r--r-- | share/man/man9/physio.9 | 36 |
1 files changed, 21 insertions, 15 deletions
diff --git a/share/man/man9/physio.9 b/share/man/man9/physio.9 index add4c640615c..38a93e06b55e 100644 --- a/share/man/man9/physio.9 +++ b/share/man/man9/physio.9 @@ -52,19 +52,21 @@ .Sh DESCRIPTION The .Fn physio -is a helper function typically called from character device read and write +is a helper function typically called from character device +.Fn read +and +.Fn write routines to start I/O on a user process buffer. -The maximum amount of data to transfer with each call -is determined by: -.Bd -literal -dev->si_iosize_max -.Ed +The maximum amount of data to transfer with each call +is determined by +.Fa dev->si_iosize_max . .Pp Since .Fa uio normally describes user space addresses, .Fn physio -needs to lock the process into memory. This is done by setting the +needs to lock the process into memory. +This is done by setting the .Dv P_PHYSIO flag on the process. .Fn physio @@ -80,9 +82,9 @@ The description of the entire transfer as requested by the user process. Currently, the results of passing a .Fa uio structure with the -.Sq uio_segflg +.Va uio_segflg set to anything other than -.Dv UIO_USERSPACE , +.Dv UIO_USERSPACE are undefined. .El .Sh RETURN VALUES @@ -103,16 +105,20 @@ field. Note that the actual transfer size may be less than requested by .Fa uio if the device signals an -.Dq end of file +.Dq "end of file" condition. .Sh SEE ALSO .Xr read 2 , .Xr write 2 .Sh HISTORY -The -.Xr physio 9 -manual page is originally from NetBSD with minor changes for applicability -with FreeBSD. +The +.Nm +manual page is originally from +.Nx +with minor changes for applicability with +.Fx . .Pp -The physio(9) call has been completely re-written for providing higher +The +.Nm +call has been completely re-written for providing higher I/O performance, and better paging performance. |