From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 470F36B025F for ; Fri, 3 Jun 2016 05:16:57 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id e3so38456690wme.3 for ; Fri, 03 Jun 2016 02:16:57 -0700 (PDT) Received: from mail-wm0-f68.google.com (mail-wm0-f68.google.com. [74.125.82.68]) by mx.google.com with ESMTPS id r4si6319809wjm.231.2016.06.03.02.16.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Jun 2016 02:16:52 -0700 (PDT) Received: by mail-wm0-f68.google.com with SMTP id n184so21522759wmn.1 for ; Fri, 03 Jun 2016 02:16:52 -0700 (PDT) From: Michal Hocko Subject: [PATCH 03/10] proc, oom_adj: extract oom_score_adj setting into a helper Date: Fri, 3 Jun 2016 11:16:37 +0200 Message-Id: <1464945404-30157-4-git-send-email-mhocko@kernel.org> In-Reply-To: <1464945404-30157-1-git-send-email-mhocko@kernel.org> References: <1464945404-30157-1-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 | 97 ++++++++++++++++++++++++++++------------------------------ 1 file changed, 46 insertions(+), 51 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 968d5ea06e62..520fa467cad0 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1037,7 +1037,50 @@ 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) { + err = -ESRCH; + goto out; + } + + 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); +out: + return err; +} /* * /proc/pid/oom_adj exists solely for backwards compatibility with previous @@ -1052,7 +1095,6 @@ 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 +1116,6 @@ 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 +1125,7 @@ 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 +1155,6 @@ 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 +1176,7 @@ 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; } -- 2.8.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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