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proc, oom_adj: extract oom_score_adj setting into a helper 

Currently we have two proc interfaces to set oom_score_adj.  The legacy
/proc/<pid>/oom_adj and /proc/<pid>/oom_score_adj which both have their
specific handlers.  Big part of the logic is duplicated so extract the
common code into __set_oom_adj helper.  Legacy knob still expects some
details slightly different so make sure those are handled same way - e.g.
the legacy mode ignores oom_score_adj_min and it warns about the usage.

This patch shouldn't introduce any functional changes.

Link: http://lkml.kernel.org/r/1466426628-15074-4-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michal Hocko 2016-07-28 15:44:40 -07:00 коммит произвёл Linus Torvalds
Родитель f913da596a
Коммит 1d5f0acbc6
1 изменённых файлов: 43 добавлений и 51 удалений
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94
fs/proc/base.c
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@ -1037,7 +1037,47 @@ static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
static DEFINE_MUTEX(oom_adj_mutex);
static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
{
static DEFINE_MUTEX(oom_adj_mutex);
struct task_struct *task;
int err = 0;
task = get_proc_task(file_inode(file));
if (!task)
return -ESRCH;
mutex_lock(&oom_adj_mutex);
if (legacy) {
if (oom_adj < task->signal->oom_score_adj &&
!capable(CAP_SYS_RESOURCE)) {
err = -EACCES;
goto err_unlock;
}
/*
* /proc/pid/oom_adj is provided for legacy purposes, ask users to use
* /proc/pid/oom_score_adj instead.
*/
pr_warn_once("%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));
} else {
if ((short)oom_adj < task->signal->oom_score_adj_min &&
!capable(CAP_SYS_RESOURCE)) {
err = -EACCES;
goto err_unlock;
}
}
task->signal->oom_score_adj = oom_adj;
if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
task->signal->oom_score_adj_min = (short)oom_adj;
trace_oom_score_adj_update(task);
err_unlock:
mutex_unlock(&oom_adj_mutex);
put_task_struct(task);
return err;
}
/*
* /proc/pid/oom_adj exists solely for backwards compatibility with previous
@ -1052,7 +1092,6 @@ static DEFINE_MUTEX(oom_adj_mutex);
static ssize_t oom_adj_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF];
int oom_adj;
int err;
@ -1074,12 +1113,6 @@ static ssize_t oom_adj_write(struct file *file, const char __user *buf,
goto out;
}
task = get_proc_task(file_inode(file));
if (!task) {
err = -ESRCH;
goto out;
}
/*
* Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
* value is always attainable.
@ -1089,26 +1122,7 @@ static ssize_t oom_adj_write(struct file *file, const char __user *buf,
else
oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
mutex_lock(&oom_adj_mutex);
if (oom_adj < task->signal->oom_score_adj &&
!capable(CAP_SYS_RESOURCE)) {
err = -EACCES;
goto err_unlock;
}
/*
* /proc/pid/oom_adj is provided for legacy purposes, ask users to use
* /proc/pid/oom_score_adj instead.
*/
pr_warn_once("%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_score_adj = oom_adj;
trace_oom_score_adj_update(task);
err_unlock:
mutex_unlock(&oom_adj_mutex);
put_task_struct(task);
err = __set_oom_adj(file, oom_adj, true);
out:
return err < 0 ? err : count;
}
@ -1138,7 +1152,6 @@ static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF];
int oom_score_adj;
int err;
@ -1160,28 +1173,7 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
goto out;
}
task = get_proc_task(file_inode(file));
if (!task) {
err = -ESRCH;
goto out;
}
mutex_lock(&oom_adj_mutex);
if ((short)oom_score_adj < task->signal->oom_score_adj_min &&
!capable(CAP_SYS_RESOURCE)) {
err = -EACCES;
goto err_unlock;
}
task->signal->oom_score_adj = (short)oom_score_adj;
if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
task->signal->oom_score_adj_min = (short)oom_score_adj;
trace_oom_score_adj_update(task);
err_unlock:
mutex_unlock(&oom_adj_mutex);
put_task_struct(task);
err = __set_oom_adj(file, oom_score_adj, false);
out:
return err < 0 ? err : count;
}