From: Michal Hocko <mhocko@xxxxxxxx> Subject: 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@xxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/base.c | 94 +++++++++++++++++++++-------------------------- 1 file changed, 43 insertions(+), 51 deletions(-) diff -puN fs/proc/base.c~proc-oom_adj-extract-oom_score_adj-setting-into-a-helper fs/proc/base.c --- a/fs/proc/base.c~proc-oom_adj-extract-oom_score_adj-setting-into-a-helper +++ a/fs/proc/base.c @@ -1037,7 +1037,47 @@ static ssize_t oom_adj_read(struct file 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 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 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 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(struc 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; } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
