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authorRobert Love <rml@tech9.net>2002-04-09 04:02:50 -0700
committerLinus Torvalds <torvalds@penguin.transmeta.com>2002-04-09 04:02:50 -0700
commit22e962f9b7a7abbc2d17ceaf3917bb8e67b68a8f (patch)
treee5a8c26a9b54e7aa0edb64ec9df335dfabe72c71
parentb96ad24ad44794ee435987291c83b77e6c6f96ac (diff)
[PATCH] cpu affinity syscallsv2.5.8-pre3
This patch implements the following calls to set and retrieve a task's CPU affinity: int sched_setaffinity(pid_t pid, unsigned int len, unsigned long *new_mask_ptr) int ched_getaffinity(pid_t pid, unsigned int len, unsigned long *user_mask_ptr)
-rw-r--r--arch/i386/kernel/entry.S2
-rw-r--r--include/asm-i386/unistd.h2
-rw-r--r--kernel/sched.c90
3 files changed, 94 insertions, 0 deletions
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 2bac29ee1963..ad7efb83dd76 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -779,6 +779,8 @@ ENTRY(sys_call_table)
.long SYMBOL_NAME(sys_tkill)
.long SYMBOL_NAME(sys_sendfile64)
.long SYMBOL_NAME(sys_futex) /* 240 */
+ .long SYMBOL_NAME(sys_sched_setaffinity)
+ .long SYMBOL_NAME(sys_sched_getaffinity)
.rept NR_syscalls-(.-sys_call_table)/4
.long SYMBOL_NAME(sys_ni_syscall)
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index 2cdad510f2b9..42517b85939b 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -245,6 +245,8 @@
#define __NR_tkill 238
#define __NR_sendfile64 239
#define __NR_futex 240
+#define __NR_sched_setaffinity 241
+#define __NR_sched_getaffinity 242
/* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
diff --git a/kernel/sched.c b/kernel/sched.c
index d1df13d565e2..bf8c9a91e008 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1234,6 +1234,96 @@ out_unlock:
return retval;
}
+/**
+ * sys_sched_setaffinity - set the cpu affinity of a process
+ * @pid: pid of the process
+ * @len: length of new_mask
+ * @new_mask: user-space pointer to the new cpu mask
+ */
+asmlinkage int sys_sched_setaffinity(pid_t pid, unsigned int len,
+ unsigned long *new_mask_ptr)
+{
+ unsigned long new_mask;
+ task_t *p;
+ int retval;
+
+ if (len < sizeof(new_mask))
+ return -EINVAL;
+
+ if (copy_from_user(&new_mask, new_mask_ptr, sizeof(new_mask)))
+ return -EFAULT;
+
+ new_mask &= cpu_online_map;
+ if (!new_mask)
+ return -EINVAL;
+
+ read_lock(&tasklist_lock);
+
+ p = find_process_by_pid(pid);
+ if (!p) {
+ read_unlock(&tasklist_lock);
+ return -ESRCH;
+ }
+
+ /*
+ * It is not safe to call set_cpus_allowed with the
+ * tasklist_lock held. We will bump the task_struct's
+ * usage count and then drop tasklist_lock.
+ */
+ get_task_struct(p);
+ read_unlock(&tasklist_lock);
+
+ retval = -EPERM;
+ if ((current->euid != p->euid) && (current->euid != p->uid) &&
+ !capable(CAP_SYS_NICE))
+ goto out_unlock;
+
+ retval = 0;
+ set_cpus_allowed(p, new_mask);
+
+out_unlock:
+ put_task_struct(p);
+ return retval;
+}
+
+/**
+ * sys_sched_getaffinity - get the cpu affinity of a process
+ * @pid: pid of the process
+ * @len: length of the new mask
+ * @user_mask_ptr: userspace pointer to the mask
+ */
+asmlinkage int sys_sched_getaffinity(pid_t pid, unsigned int len,
+ unsigned long *user_mask_ptr)
+{
+ unsigned long mask;
+ unsigned int real_len;
+ task_t *p;
+ int retval;
+
+ real_len = sizeof(mask);
+
+ if (len < real_len)
+ return -EINVAL;
+
+ read_lock(&tasklist_lock);
+
+ retval = -ESRCH;
+ p = find_process_by_pid(pid);
+ if (!p)
+ goto out_unlock;
+
+ retval = 0;
+ mask = p->cpus_allowed & cpu_online_map;
+
+out_unlock:
+ read_unlock(&tasklist_lock);
+ if (retval)
+ return retval;
+ if (copy_to_user(user_mask_ptr, &mask, real_len))
+ return -EFAULT;
+ return real_len;
+}
+
asmlinkage long sys_sched_yield(void)
{
runqueue_t *rq;