Re: [PATCH] make setpriority POSIX compliant; introduce PRIO_THREAD extension

Denys Vlasenko
2008-09-01T14:43:43Z

On Mon, 2008-09-01 at 16:12 +0200, Denys Vlasenko wrote:
> Patch is run tested. I will post test program etc as a reply.

Looks like Evolution word-wrapped the patch. Let me try again.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
--
vda

diff --git a/include/linux/resource.h b/include/linux/resource.h
index aaa423a..f292690 100644
--- a/include/linux/resource.h
+++ b/include/linux/resource.h
@@ -51,6 +51,7 @@ struct rlimit {
#define PRIO_PROCESS 0
#define PRIO_PGRP 1
#define PRIO_USER 2
+#define PRIO_THREAD 3

/*
* Limit the stack by to some sane default: root can always
diff --git a/kernel/sys.c b/kernel/sys.c
index 038a7bc..d339c1a 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -142,9 +142,9 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)
struct task_struct *g, *p;
struct user_struct *user;
int error = -EINVAL;
- struct pid *pgrp;
+ struct pid *pgrp, *pid;

- if (which > PRIO_USER || which < PRIO_PROCESS)
+ if (which > PRIO_THREAD || which < PRIO_PROCESS)
goto out;

/* normalize: avoid signed division (rounding problems) */
@@ -156,7 +156,7 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)

read_lock(&tasklist_lock);
switch (which) {
- case PRIO_PROCESS:
+ case PRIO_THREAD:
if (who)
p = find_task_by_vpid(who);
else
@@ -164,6 +164,19 @@ asmlinkage long sys_setpriority(int which, int who, int niceval)
if (p)
error = set_one_prio(p, niceval, error);
break;
+ case PRIO_PROCESS:
+ if (who)
+ pid = find_vpid(who);
+ else {
+ pid = task_pid(current);
+ who = current->pid;
+ }
+ do_each_pid_thread(pid, PIDTYPE_PID, p) {
+ if (who == p->pid || who == p->tgid) {
+ error = set_one_prio(p, niceval, error);
+ }
+ } while_each_pid_thread(pid, PIDTYPE_PID, p);
+ break;
case PRIO_PGRP:
if (who)
pgrp = find_vpid(who);
@@ -206,14 +219,14 @@ asmlinkage long sys_getpriority(int which, int who)
struct task_struct *g, *p;
struct user_struct *user;
long niceval, retval = -ESRCH;
- struct pid *pgrp;
+ struct pid *pgrp, *pid;

- if (which > PRIO_USER || which < PRIO_PROCESS)
+ if (which > PRIO_THREAD || which < PRIO_PROCESS)
return -EINVAL;

read_lock(&tasklist_lock);
switch (which) {
- case PRIO_PROCESS:
+ case PRIO_THREAD:
if (who)
p = find_task_by_vpid(who);
else
@@ -224,6 +237,21 @@ asmlinkage long sys_getpriority(int which, int who)
retval = niceval;
}
break;
+ case PRIO_PROCESS:
+ if (who)
+ pid = find_vpid(who);
+ else {
+ pid = task_pid(current);
+ who = current->pid;
+ }
+ do_each_pid_thread(pid, PIDTYPE_PID, p) {
+ if (who == p->pid || who == p->tgid) {
+ niceval = 20 - task_nice(p);
+ if (niceval > retval)
+ retval = niceval;
+ }
+ } while_each_pid_thread(pid, PIDTYPE_PID, p);
+ break;
case PRIO_PGRP:
if (who)
pgrp = find_vpid(who);