process-cpp  3.0.0
A simple convenience library for handling processes in C++11.
oom_adj.cpp
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1 /*
2  * Copyright © 2013 Canonical Ltd.
3  *
4  * This program is free software: you can redistribute it and/or modify it
5  * under the terms of the GNU Lesser General Public License version 3,
6  * as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11  * GNU Lesser General Public License for more details.
12  *
13  * You should have received a copy of the GNU Lesser General Public License
14  * along with this program. If not, see <http://www.gnu.org/licenses/>.
15  *
16  * Authored by: Thomas Voß <thomas.voss@canonical.com>
17  */
18 
20 
21 #include <core/posix/process.h>
22 
23 #include <fstream>
24 #include <sstream>
25 #include <stdexcept>
26 
27 #include <linux/oom.h>
28 
29 namespace core
30 {
31 namespace posix
32 {
33 namespace linux
34 {
35 namespace proc
36 {
37 namespace process
38 {
39 
41 {
42  return OOM_DISABLE;
43 }
44 
46 {
47  return OOM_ADJUST_MIN;
48 }
49 
51 {
52  return OOM_ADJUST_MAX;
53 }
54 
55 const posix::Process& operator>>(const posix::Process& process, OomAdj& adj)
56 {
57  std::stringstream ss; ss << "/proc/" << process.pid() << "/oom_adj";
58  std::ifstream in(ss.str());
59 
60  in >> adj.value;
61 
62  return process;
63 }
64 
65 const posix::Process& operator<<(const posix::Process& process, const OomAdj& adj)
66 {
67  if (!adj.is_valid())
68  throw std::logic_error("Value for adjusting the oom score is invalid.");
69 
70  std::stringstream ss; ss << "/proc/" << process.pid() << "/oom_adj";
71  std::ofstream out(ss.str());
72 
73  out << adj.value;
74 
75  return process;
76 }
77 }
78 }
79 }
80 }
81 }
static int max_value()
Returns the maximum valid value.
Definition: oom_adj.cpp:50
The Process class models a process and possible operations on it.
Definition: process.h:44
static int disable_value()
Returns the value that makes a process "invisible" to the oom killer.
Definition: oom_adj.cpp:40
CORE_POSIX_DLL_PUBLIC const posix::Process & operator>>(const posix::Process &process, OomAdj &adj)
Read the OomAdj value for a process instance.
Definition: oom_adj.cpp:55
virtual pid_t pid() const
Query the pid of the process.
Definition: process.cpp:59
static int min_value()
Returns the minimum valid value.
Definition: oom_adj.cpp:45
bool is_valid() const
is_valid checks whether the contained value is within the predefined bounds.
Definition: oom_adj.h:74
CORE_POSIX_DLL_PUBLIC const posix::Process & operator<<(const posix::Process &process, const OomAdj &adj)
Write the OomAdj value for a process instance.
Definition: oom_adj.cpp:65