Hi, I've attached another revision of the patch. It behaves basically the same as before, but I've completely re-written the code in the style of the --procsched example you already did in git.
Sorry for the delay, I've been busy with a few other things. > Thanks for improving the patch. Could you also document the new option > in the man page? > Could you add a check in configure.ac for the 'sys/syscall.h' header > as it's not present in all systems? > > No camel case plase. :) These are all fixed now. > The less globals used the better, you should be able to use the new > 'struct res_schedule' to hold some of this data, the rest should be > moved to an inner scope. That is done now. I've used just a single global - the same as the code for --procsched I think. > Try to define the function early on so that we don't need a prototype > for a static function. Done. I've moved the function to earlier in the source file and got rid of the prototype. > This should not be conditional, we always want the help available. > Also this would cause problems in case we wanted to add i18n support > here later on. Also it should be less than 80 chars wide. This is not conditional in the new version, and I've truncated it and put it on 2 rows. > I think probably better name this 'iosched', in line with 'procsched'. Agreed, and fixed. > Here only save optarg, and do the parsing and validation later on in > this same function. And you can use now xstrdup. Done, in the same was as the parsing for --procsched. > Indent the case at the same level as the switch, and no need for the > parenthesis in the case. Fixed the indenting, bug I couldn't get it to compile without the parenthesis in the case. > You can use parse_integer instead. Fixed. And the error checking in parse_integer is better than the error checking I implemented when I used strtol anyway. > We want as much validation as possible to happen always, so that a > packager trying this on an unsupported system would get a meaningful > error then, instead of having to wait for someone to run it and get it > to fail on a supported system. Fixed. There is validation on both <class> and <data> now. > The values to be printed should be on the code dealing with --test. Fixed. > Better to move this part into its own function. Done. I created a new function "set_io_sched". Let me know if there are any problems. Thanks Chris
diff -Nurp dpkg/configure.ac dpkg.new/configure.ac
--- dpkg/configure.ac 2009-01-23 19:43:17.000000000 +0000
+++ dpkg.new/configure.ac 2009-01-23 18:31:35.000000000 +0000
@@ -73,7 +73,7 @@ fi
# Checks for header files.
AC_HEADER_STDC
-AC_CHECK_HEADERS([stddef.h error.h locale.h libintl.h sys/cdefs.h kvm.h])
+AC_CHECK_HEADERS([stddef.h error.h locale.h libintl.h sys/cdefs.h kvm.h sys/syscall.h])
DPKG_CHECK_DEFINE(TIOCNOTTY, [sys/ioctl.h])
# Checks for typedefs, structures, and compiler characteristics.
diff -Nurp dpkg/man/start-stop-daemon.8 dpkg.new/man/start-stop-daemon.8
--- dpkg/man/start-stop-daemon.8 2009-01-23 19:43:19.000000000 +0000
+++ dpkg.new/man/start-stop-daemon.8 2009-01-23 21:21:47.000000000 +0000
@@ -219,6 +219,13 @@ code for them to do this themselves.
.BR \-N ", " \-\-nicelevel " \fIint\fP"
This alters the priority of the process before starting it.
.TP
+.BR \-I ", " \-\-iosched " \fIclass\fP\fB:\fP\fIdata\fP"
+This alters the IO scheduler class and data of the process before starting
+it. The data can be optionally specified by appending a \fB:\fP followed
+by the value. The default \fIdata\fP is 4, unless \fIclass\fP is \fBidle\fP,
+when \fIdata\fP will always be 7. The currently supported values for
+\fIclass\fP are \fBidle\fP, \fBbest-effort\fP and \fBreal-time\fP.
+.TP
.BR \-P ", " \-\-procsched " \fIpolicy\fP\fB:\fP\fIpriority\fP"
This alters the process scheduler policy and priority of the process before
starting it. The priority can be optionally specified by appending a \fB:\fP
diff -Nurp dpkg/utils/start-stop-daemon.c dpkg.new/utils/start-stop-daemon.c
--- dpkg/utils/start-stop-daemon.c 2009-01-23 19:43:20.000000000 +0000
+++ dpkg.new/utils/start-stop-daemon.c 2009-01-23 21:28:19.000000000 +0000
@@ -111,6 +111,27 @@
#include <error.h>
#endif
+#ifdef HAVE_SYS_SYSCALL_H
+#include <sys/syscall.h>
+#endif
+
+#if defined(SYS_ioprio_set) && defined(linux)
+ #define SUPPORT_IOPRIO_SET
+#endif
+
+enum {
+ IOPRIO_WHO_PROCESS = 1,
+ IOPRIO_WHO_PGRP,
+ IOPRIO_WHO_USER,
+};
+
+enum {
+ IOPRIO_CLASS_NONE,
+ IOPRIO_CLASS_RT,
+ IOPRIO_CLASS_BE,
+ IOPRIO_CLASS_IDLE,
+};
+
static int testmode = 0;
static int quietmode = 0;
static int exitnodo = 1;
@@ -136,6 +157,11 @@ static const char *progname = "";
static int nicelevel = 0;
static int umask_value = -1;
+#define IOPRIO_CLASS_SHIFT 13
+#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
+#define IO_SCHED_DATA_MIN 0
+#define IO_SCHED_DATA_MAX 7
+
static struct stat exec_stat;
#if defined(OSHURD)
static struct proc_stat_list *procset = NULL;
@@ -168,6 +194,7 @@ struct schedule_item {
};
static struct res_schedule *proc_sched = NULL;
+static struct res_schedule *io_sched = NULL;
static int schedule_length;
static struct schedule_item *schedule = NULL;
@@ -336,6 +363,9 @@ do_help(void)
" -r|--chroot <directory> chroot to <directory> before starting\n"
" -d|--chdir <directory> change to <directory> (default is /)\n"
" -N|--nicelevel <incr> add incr to the process's nice level\n"
+" -I|--iosched <class>:<data>\n"
+" use <class> with <data> to set the IO\n"
+" scheduler (default data is 4)\n"
" -P|--procsched <policy[:prio]>\n"
" use <policy> with <prio> for the kernel\n"
" process scheduler (default prio is 0)\n"
@@ -493,6 +523,58 @@ parse_proc_schedule(const char *string)
}
static void
+parse_iosched(const char *string)
+{
+ char *class_str, *data_str;
+ int data = 0;
+
+ class_str = xstrdup(string);
+ class_str = strtok(class_str, ":");
+ data_str = strtok(NULL, ":");
+
+ if (data_str && parse_integer(data_str, &data) != 0)
+ fatal("Invalid IO scheduler data string");
+
+ io_sched = xmalloc(sizeof(*io_sched));
+ io_sched->policy_name = class_str;
+
+ if (strcmp(class_str, "real-time") == 0) {
+ io_sched->policy = IOPRIO_CLASS_RT;
+ } else if (strcmp(class_str, "best-effort") == 0) {
+ io_sched->policy = IOPRIO_CLASS_BE;
+ } else if (strcmp(class_str, "idle") == 0) {
+ io_sched->policy = IOPRIO_CLASS_IDLE;
+ } else {
+ badusage("Unrecognized IO scheduler class");
+ }
+
+ switch (io_sched->policy) {
+ case (IOPRIO_CLASS_IDLE):
+ io_sched->priority = 7;
+ break;
+ default:
+ if (data_str != NULL) {
+ io_sched->priority = data;
+ } else {
+ io_sched->priority = 4;
+ }
+ }
+
+ if (io_sched->priority < IO_SCHED_DATA_MIN)
+ badusage("IO scheduler data less than min");
+ if (io_sched->priority > IO_SCHED_DATA_MAX)
+ badusage("IO scheduler data greater than max");
+}
+
+#ifdef SUPPORT_IOPRIO_SET
+static inline int
+ioprio_set (int which, int who, int ioprio)
+{
+ return syscall(SYS_ioprio_set, which, who, ioprio);
+}
+#endif
+
+static void
set_proc_schedule(struct res_schedule *sched)
{
#ifdef _POSIX_PRIORITY_SCHEDULING
@@ -506,6 +588,19 @@ set_proc_schedule(struct res_schedule *s
}
static void
+set_io_sched(struct res_schedule *sched)
+{
+#ifdef SUPPORT_IOPRIO_SET
+ int io_sched_mask;
+
+ io_sched_mask = IOPRIO_PRIO_VALUE(sched->policy, sched->priority);
+ if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), io_sched_mask) == -1)
+ fatal("Unable to alter IO priority to mask %i",
+ io_sched_mask);
+#endif
+}
+
+static void
parse_schedule_item(const char *string, struct schedule_item *item)
{
const char *after_hyph;
@@ -606,6 +701,7 @@ parse_options(int argc, char * const *ar
{ "exec", 1, NULL, 'x'},
{ "chuid", 1, NULL, 'c'},
{ "nicelevel", 1, NULL, 'N'},
+ { "iosched", 1, NULL, 'I'},
{ "procsched", 1, NULL, 'P'},
{ "umask", 1, NULL, 'k'},
{ "background", 0, NULL, 'b'},
@@ -618,11 +714,12 @@ parse_options(int argc, char * const *ar
const char *signal_str = NULL;
const char *schedule_str = NULL;
const char *proc_schedule_str = NULL;
+ const char *io_sched_str = NULL;
int c;
for (;;) {
c = getopt_long(argc, argv,
- "HKSVa:n:op:qr:s:tu:vx:c:N:P:k:bmR:g:d:",
+ "HKSVa:n:op:qr:s:tu:vx:c:N:I:P:k:bmR:g:d:",
longopts, NULL);
if (c == -1)
break;
@@ -685,6 +782,9 @@ parse_options(int argc, char * const *ar
case 'N': /* --nice */
nicelevel = atoi(optarg);
break;
+ case 'I': /* --iosched */
+ io_sched_str = optarg;
+ break;
case 'P': /* --procsched */
proc_schedule_str = optarg;
break;
@@ -720,6 +820,9 @@ parse_options(int argc, char * const *ar
if (proc_schedule_str != NULL)
parse_proc_schedule(proc_schedule_str);
+
+ if (io_sched_str != NULL)
+ parse_iosched(io_sched_str);
if (umask_str != NULL) {
if (parse_umask(umask_str, &umask_value) != 0)
@@ -1410,6 +1513,9 @@ main(int argc, char **argv)
if (proc_sched)
printf(", with scheduling policy %s with priority %i",
proc_sched->policy_name, proc_sched->priority);
+ if (io_sched)
+ printf(", and with IO scheduling class %s and data %i",
+ io_sched->policy_name, io_sched->priority);
printf(".\n");
}
if (testmode)
@@ -1431,6 +1537,8 @@ main(int argc, char **argv)
fatal("Unable to alter nice level by %i: %s",
nicelevel, strerror(errno));
}
+ if (io_sched)
+ set_io_sched(io_sched);
if (proc_sched)
set_proc_schedule(proc_sched);
if (umask_value >= 0)
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