oom: remove deprecated oom_adj (01dc52eb) · Commits · e / devices / android_kernel_xiaomi_markw

Documentation/ABI/obsolete/proc-pid-oom_adj

deleted100644 → 0

+0 −22

Original line number	Diff line number	Diff line
		What: /proc/<pid>/oom_adj
		When: August 2012
		Why: /proc/<pid>/oom_adj allows userspace to influence the oom killer's
		badness heuristic used to determine which task to kill when the kernel
		is out of memory.

		The badness heuristic has since been rewritten since the introduction of
		this tunable such that its meaning is deprecated. The value was
		implemented as a bitshift on a score generated by the badness()
		function that did not have any precise units of measure. With the
		rewrite, the score is given as a proportion of available memory to the
		task allocating pages, so using a bitshift which grows the score
		exponentially is, thus, impossible to tune with fine granularity.

		A much more powerful interface, /proc/<pid>/oom_score_adj, was
		introduced with the oom killer rewrite that allows users to increase or
		decrease the badness score linearly. This interface will replace
		/proc/<pid>/oom_adj.

		A warning will be emitted to the kernel log if an application uses this
		deprecated interface. After it is printed once, future warnings will be
		suppressed until the kernel is rebooted.

Documentation/filesystems/proc.txt

+4 −18

Original line number	Diff line number	Diff line
		@@ -33,7 +33,7 @@ Table of Contents
		2 Modifying System Parameters

		3 Per-Process Parameters
		3.1 /proc/<pid>/oom_adj & /proc/<pid>/oom_score_adj - Adjust the oom-killer
		3.1 /proc/<pid>/oom_score_adj - Adjust the oom-killer
		score
		3.2 /proc/<pid>/oom_score - Display current oom-killer score
		3.3 /proc/<pid>/io - Display the IO accounting fields
		@@ -1320,10 +1320,10 @@ of the kernel.
		CHAPTER 3: PER-PROCESS PARAMETERS
		------------------------------------------------------------------------------

		3.1 /proc/<pid>/oom_adj & /proc/<pid>/oom_score_adj- Adjust the oom-killer score
		3.1 /proc/<pid>/oom_score_adj- Adjust the oom-killer score
		--------------------------------------------------------------------------------

		These file can be used to adjust the badness heuristic used to select which
		This file can be used to adjust the badness heuristic used to select which
		process gets killed in out of memory conditions.

		The badness heuristic assigns a value to each candidate task ranging from 0
		@@ -1361,22 +1361,10 @@ same system, cpuset, mempolicy, or memory controller resources to use at least
		equivalent to discounting 50% of the task's allowed memory from being considered
		as scoring against the task.

		For backwards compatibility with previous kernels, /proc/<pid>/oom_adj may also
		be used to tune the badness score. Its acceptable values range from -16
		(OOM_ADJUST_MIN) to +15 (OOM_ADJUST_MAX) and a special value of -17
		(OOM_DISABLE) to disable oom killing entirely for that task. Its value is
		scaled linearly with /proc/<pid>/oom_score_adj.

		Writing to /proc/<pid>/oom_score_adj or /proc/<pid>/oom_adj will change the
		other with its scaled value.

		The value of /proc/<pid>/oom_score_adj may be reduced no lower than the last
		value set by a CAP_SYS_RESOURCE process. To reduce the value any lower
		requires CAP_SYS_RESOURCE.

		NOTICE: /proc/<pid>/oom_adj is deprecated and will be removed, please see
		Documentation/feature-removal-schedule.txt.

		Caveat: when a parent task is selected, the oom killer will sacrifice any first
		generation children with separate address spaces instead, if possible. This
		avoids servers and important system daemons from being killed and loses the
		@@ -1387,9 +1375,7 @@ minimal amount of work.
		-------------------------------------------------------------

		This file can be used to check the current score used by the oom-killer is for
		any given <pid>. Use it together with /proc/<pid>/oom_adj to tune which
		process should be killed in an out-of-memory situation.

		any given <pid>.

		3.3 /proc/<pid>/io - Display the IO accounting fields
		-------------------------------------------------------

fs/proc/base.c

+1 −116

Original line number	Diff line number	Diff line
		@@ -873,111 +873,6 @@ static const struct file_operations proc_environ_operations = {
		.release = mem_release,
		};

		static ssize_t oom_adjust_read(struct file file, char __user buf,
		size_t count, loff_t *ppos)
		{
		struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
		char buffer[PROC_NUMBUF];
		size_t len;
		int oom_adjust = OOM_DISABLE;
		unsigned long flags;

		if (!task)
		return -ESRCH;

		if (lock_task_sighand(task, &flags)) {
		oom_adjust = task->signal->oom_adj;
		unlock_task_sighand(task, &flags);
		}

		put_task_struct(task);

		len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust);

		return simple_read_from_buffer(buf, count, ppos, buffer, len);
		}

		static ssize_t oom_adjust_write(struct file file, const char __user buf,
		size_t count, loff_t *ppos)
		{
		struct task_struct *task;
		char buffer[PROC_NUMBUF];
		int oom_adjust;
		unsigned long flags;
		int err;

		memset(buffer, 0, sizeof(buffer));
		if (count > sizeof(buffer) - 1)
		count = sizeof(buffer) - 1;
		if (copy_from_user(buffer, buf, count)) {
		err = -EFAULT;
		goto out;
		}

		err = kstrtoint(strstrip(buffer), 0, &oom_adjust);
		if (err)
		goto out;
		if ((oom_adjust < OOM_ADJUST_MIN \|\| oom_adjust > OOM_ADJUST_MAX) &&
		oom_adjust != OOM_DISABLE) {
		err = -EINVAL;
		goto out;
		}

		task = get_proc_task(file->f_path.dentry->d_inode);
		if (!task) {
		err = -ESRCH;
		goto out;
		}

		task_lock(task);
		if (!task->mm) {
		err = -EINVAL;
		goto err_task_lock;
		}

		if (!lock_task_sighand(task, &flags)) {
		err = -ESRCH;
		goto err_task_lock;
		}

		if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) {
		err = -EACCES;
		goto err_sighand;
		}

		/*
		* Warn that /proc/pid/oom_adj is deprecated, see
		* Documentation/feature-removal-schedule.txt.
		*/
		printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
		current->comm, task_pid_nr(current), task_pid_nr(task),
		task_pid_nr(task));
		task->signal->oom_adj = oom_adjust;
		/*
		* Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
		* value is always attainable.
		*/
		if (task->signal->oom_adj == OOM_ADJUST_MAX)
		task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX;
		else
		task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
		-OOM_DISABLE;
		trace_oom_score_adj_update(task);
		err_sighand:
		unlock_task_sighand(task, &flags);
		err_task_lock:
		task_unlock(task);
		put_task_struct(task);
		out:
		return err < 0 ? err : count;
		}

		static const struct file_operations proc_oom_adjust_operations = {
		.read = oom_adjust_read,
		.write = oom_adjust_write,
		.llseek = generic_file_llseek,
		};

		static ssize_t oom_score_adj_read(struct file file, char __user buf,
		size_t count, loff_t *ppos)
		{
		@@ -1051,15 +946,7 @@ static ssize_t oom_score_adj_write(struct file file, const char __user buf,
		if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
		task->signal->oom_score_adj_min = oom_score_adj;
		trace_oom_score_adj_update(task);
		/*
		* Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
		* always attainable.
		*/
		if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
		task->signal->oom_adj = OOM_DISABLE;
		else
		task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) /
		OOM_SCORE_ADJ_MAX;

		err_sighand:
		unlock_task_sighand(task, &flags);
		err_task_lock:
		@@ -2710,7 +2597,6 @@ static const struct pid_entry tgid_base_stuff[] = {
		REG("cgroup", S_IRUGO, proc_cgroup_operations),
		#endif
		INF("oom_score", S_IRUGO, proc_oom_score),
		REG("oom_adj", S_IRUGO\|S_IWUSR, proc_oom_adjust_operations),
		REG("oom_score_adj", S_IRUGO\|S_IWUSR, proc_oom_score_adj_operations),
		#ifdef CONFIG_AUDITSYSCALL
		REG("loginuid", S_IWUSR\|S_IRUGO, proc_loginuid_operations),
		@@ -3077,7 +2963,6 @@ static const struct pid_entry tid_base_stuff[] = {
		REG("cgroup", S_IRUGO, proc_cgroup_operations),
		#endif
		INF("oom_score", S_IRUGO, proc_oom_score),
		REG("oom_adj", S_IRUGO\|S_IWUSR, proc_oom_adjust_operations),
		REG("oom_score_adj", S_IRUGO\|S_IWUSR, proc_oom_score_adj_operations),
		#ifdef CONFIG_AUDITSYSCALL
		REG("loginuid", S_IWUSR\|S_IRUGO, proc_loginuid_operations),

include/linux/oom.h

+0 −11

Original line number	Diff line number	Diff line
		#ifndef __INCLUDE_LINUX_OOM_H
		#define __INCLUDE_LINUX_OOM_H

		/*
		* /proc/<pid>/oom_adj is deprecated, see
		* Documentation/feature-removal-schedule.txt.
		*
		* /proc/<pid>/oom_adj set to -17 protects from the oom-killer
		*/
		#define OOM_DISABLE (-17)
		/* inclusive */
		#define OOM_ADJUST_MIN (-16)
		#define OOM_ADJUST_MAX 15

		/*
		* /proc/<pid>/oom_score_adj set to OOM_SCORE_ADJ_MIN disables oom killing for
		* pid.

include/linux/sched.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -671,7 +671,6 @@ struct signal_struct {
		struct rw_semaphore group_rwsem;
		#endif

		int oom_adj; /* OOM kill score adjustment (bit shift) */
		int oom_score_adj; /* OOM kill score adjustment */
		int oom_score_adj_min; /* OOM kill score adjustment minimum value.
		* Only settable by CAP_SYS_RESOURCE. */