diff options
author | Ruchi Kandoi <kandoiruchi@google.com> | 2014-04-18 14:07:28 -0700 |
---|---|---|
committer | Ruchi Kandoi <kandoiruchi@google.com> | 2015-02-04 14:10:16 -0800 |
commit | 017b518b3751d8256fb740470ae85f70a0853dc4 (patch) | |
tree | 5a97a5a6599b91e75cba0ac9694c44768f165d13 | |
parent | 53b5e2f0b1cebfd3493ba8ba3bb9d14924a9fa11 (diff) |
prctl: adds PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread.
Second argument is similar to PR_SET_TIMERSLACK, if non-zero then the
slack is set to that value otherwise sets it to the default for the thread.
Takes PID of the thread as the third argument.
This allows power/performance management software to set timer slack for
other threads according to its policy for the thread (such as when the
thread is designated foreground vs. background activity)
Change-Id: I744d451ff4e60dae69f38f53948ff36c51c14a3f
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
-rw-r--r-- | include/uapi/linux/prctl.h | 6 | ||||
-rw-r--r-- | kernel/sys.c | 19 |
2 files changed, 25 insertions, 0 deletions
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 80d4382cfe23..933ff2a9a032 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -179,6 +179,12 @@ struct prctl_mm_map { #define PR_SET_THP_DISABLE 41 #define PR_GET_THP_DISABLE 42 +/* Sets the timerslack for arbitrary threads + * arg2 slack value, 0 means "use default" + * arg3 pid of the thread whose timer slack needs to be set + */ +#define PR_SET_TIMERSLACK_PID 43 + #define PR_SET_VMA 0x53564d41 # define PR_SET_VMA_ANON_NAME 0 diff --git a/kernel/sys.c b/kernel/sys.c index f2c175938243..787b19740b00 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -43,6 +43,7 @@ #include <linux/ctype.h> #include <linux/mm.h> #include <linux/mempolicy.h> +#include <linux/sched.h> #include <linux/compat.h> #include <linux/syscalls.h> @@ -2178,6 +2179,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) { struct task_struct *me = current; + struct task_struct *tsk; unsigned char comm[sizeof(me->comm)]; long error; @@ -2301,6 +2303,23 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, else return -EINVAL; break; + case PR_SET_TIMERSLACK_PID: + rcu_read_lock(); + tsk = find_task_by_pid_ns((pid_t)arg3, &init_pid_ns); + if (tsk == NULL) { + rcu_read_unlock(); + return -EINVAL; + } + get_task_struct(tsk); + rcu_read_unlock(); + if (arg2 <= 0) + tsk->timer_slack_ns = + tsk->default_timer_slack_ns; + else + tsk->timer_slack_ns = arg2; + put_task_struct(tsk); + error = 0; + break; default: return -EINVAL; } |