ping On Mon, Jun 4, 2012 at 3:43 PM, Colin McCabe <cmccabe@xxxxxxxxxxxxxx> wrote: > From: Colin Patrick McCabe <cmccabe@xxxxxxxxxxxxxx> > > Signed-off-by: Colin McCabe <cmccabe@xxxxxxxxxxxxxx> > --- > man2/ioprio_set.2 | 25 ++++++++++++++++++++++--- > 1 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/man2/ioprio_set.2 b/man2/ioprio_set.2 > index 37b4dc1..807c655 100644 > --- a/man2/ioprio_set.2 > +++ b/man2/ioprio_set.2 > @@ -36,13 +36,13 @@ The > and > .BR ioprio_set () > system calls respectively get and set the I/O scheduling class and > -priority of one or more processes. > +priority of one or more threads. > > The > .I which > and > .I who > -arguments identify the process(es) on which the system > +arguments identify the thead(s) on which the system > calls operate. > The > .I which > @@ -52,7 +52,7 @@ is interpreted, and has one of the following values: > .TP > .B IOPRIO_WHO_PROCESS > .I who > -is a process ID identifying a single process. > +is a process ID or thread ID identifying a single process or thread. > .TP > .B IOPRIO_WHO_PGRP > .I who > @@ -186,6 +186,25 @@ kernel 2.6.13. > .SH "CONFORMING TO" > These system calls are Linux-specific. > .SH NOTES > +Two or more processes or threads can share an I/O context. This will be the > +case when > +.BR clone (2) > +was called with the > +.B CLONE_IO > +flag. > + > +However, by default, the distinct threads of a process will > +.B not > +share the same I/O context. This means that if you want to change the I/O > +priority of all threads in a process, you may need to call > +.BR ioprio_set() > +on all of the threads. The thread ID you would need for this operation is that > +which is returned by > +.BR gettid(), > +not > +.BR pthread_self() > +or another userspace API. > + > Glibc does not provide wrapper for these system calls; call them using > .BR syscall (2). > > -- > 1.7.7 > -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
