From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f197.google.com (mail-lb0-f197.google.com [209.85.217.197]) by kanga.kvack.org (Postfix) with ESMTP id 714656B0261 for ; Thu, 26 May 2016 08:40:29 -0400 (EDT) Received: by mail-lb0-f197.google.com with SMTP id rs7so38989291lbb.2 for ; Thu, 26 May 2016 05:40:29 -0700 (PDT) Received: from mail-wm0-f67.google.com (mail-wm0-f67.google.com. [74.125.82.67]) by mx.google.com with ESMTPS id c10si4456424wmf.52.2016.05.26.05.40.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 26 May 2016 05:40:26 -0700 (PDT) Received: by mail-wm0-f67.google.com with SMTP id a136so5050293wme.0 for ; Thu, 26 May 2016 05:40:26 -0700 (PDT) From: Michal Hocko Subject: [PATCH 2/6] proc, oom_adj: extract oom_score_adj setting into a helper Date: Thu, 26 May 2016 14:40:11 +0200 Message-Id: <1464266415-15558-3-git-send-email-mhocko@kernel.org> In-Reply-To: <1464266415-15558-1-git-send-email-mhocko@kernel.org> References: <1464266415-15558-1-git-send-email-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Tetsuo Handa , David Rientjes , Oleg Nesterov , Vladimir Davydov , Andrew Morton , LKML , Michal Hocko From: Michal Hocko Currently we have two proc interfaces to set oom_score_adj. The legacy /proc//oom_adj and /proc//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. Signed-off-by: Michal Hocko --- fs/proc/base.c | 133 +++++++++++++++++++++++++-------------------------------- 1 file changed, 59 insertions(+), 74 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index be73f4d0cb01..23679673bf5a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1041,6 +1041,63 @@ 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 int __set_oom_adj(struct file *file, int oom_adj, bool legacy) +{ + struct task_struct *task; + unsigned long flags; + int err = 0; + + task = get_proc_task(file_inode(file)); + 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 (legacy) { + if (oom_adj < task->signal->oom_score_adj && + !capable(CAP_SYS_RESOURCE)) { + err = -EACCES; + goto err_sighand; + } + /* + * /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_sighand; + } + } + + 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_sighand: + unlock_task_sighand(task, &flags); +err_task_lock: + task_unlock(task); + put_task_struct(task); +out: + return err; +} + /* * /proc/pid/oom_adj exists solely for backwards compatibility with previous * kernels. The effective policy is defined by oom_score_adj, which has a @@ -1054,10 +1111,8 @@ static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count, 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; - unsigned long flags; int err; memset(buffer, 0, sizeof(buffer)); @@ -1077,23 +1132,6 @@ 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; - } - - task_lock(task); - if (!task->mm) { - err = -EINVAL; - goto err_task_lock; - } - - if (!lock_task_sighand(task, &flags)) { - err = -ESRCH; - goto err_task_lock; - } - /* * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum * value is always attainable. @@ -1103,27 +1141,8 @@ static ssize_t oom_adj_write(struct file *file, const char __user *buf, else oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE; - if (oom_adj < task->signal->oom_score_adj && - !capable(CAP_SYS_RESOURCE)) { - err = -EACCES; - goto err_sighand; - } - - /* - * /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)); + err = __set_oom_adj(file, oom_adj, true); - task->signal->oom_score_adj = oom_adj; - 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; } @@ -1157,9 +1176,7 @@ 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]; - unsigned long flags; int oom_score_adj; int err; @@ -1180,39 +1197,7 @@ 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; - } - - 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 ((short)oom_score_adj < task->signal->oom_score_adj_min && - !capable(CAP_SYS_RESOURCE)) { - err = -EACCES; - goto err_sighand; - } - - 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_sighand: - unlock_task_sighand(task, &flags); -err_task_lock: - task_unlock(task); - put_task_struct(task); + err = __set_oom_adj(file, oom_score_adj, false); out: return err < 0 ? err : count; } -- 2.8.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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