This patch implements a procfs interface for soft CPU rate caps.
Via files of the form /proc/<tgid>/task/<pid>/cpu_rate_cap.
Signed-off-by: Peter Williams <[EMAIL PROTECTED]>
fs/proc/base.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/Kconfig.caps | 5 ++++
2 files changed, 64 insertions(+)
Index: MM-2.6.17-mm1/fs/proc/base.c
===================================================================
--- MM-2.6.17-mm1.orig/fs/proc/base.c 2006-06-22 09:27:19.000000000 +1000
+++ MM-2.6.17-mm1/fs/proc/base.c 2006-06-22 10:40:18.000000000 +1000
@@ -168,6 +168,9 @@ enum pid_directory_inos {
#ifdef CONFIG_CPUSETS
PROC_TID_CPUSET,
#endif
+#ifdef CONFIG_CPU_RATE_CAPS
+ PROC_TID_CPU_RATE_CAP,
+#endif
#ifdef CONFIG_SECURITY
PROC_TID_ATTR,
PROC_TID_ATTR_CURRENT,
@@ -282,6 +285,9 @@ static struct pid_entry tid_base_stuff[]
#ifdef CONFIG_AUDITSYSCALL
E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
+#ifdef CONFIG_CPU_RATE_CAPS
+ E(PROC_TID_CPU_RATE_CAP, "cpu_rate_cap", S_IFREG|S_IRUGO|S_IWUSR),
+#endif
{0,0,NULL,0}
};
@@ -1041,6 +1047,54 @@ static struct file_operations proc_secco
};
#endif /* CONFIG_SECCOMP */
+#ifdef CONFIG_CPU_RATE_CAPS
+static ssize_t cpu_rate_cap_read(struct file * file, char * buf,
+ size_t count, loff_t *ppos)
+{
+ struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
+ char buffer[64];
+ size_t len;
+ unsigned int cppt = get_cpu_rate_cap(task);
+
+ if (*ppos)
+ return 0;
+ *ppos = len = sprintf(buffer, "%u\n", cppt);
+ if (copy_to_user(buf, buffer, len))
+ return -EFAULT;
+
+ return len;
+}
+
+static ssize_t cpu_rate_cap_write(struct file * file, const char * buf,
+ size_t count, loff_t *ppos)
+{
+ struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
+ char buffer[128] = "";
+ char *endptr = NULL;
+ unsigned long hcppt;
+ int res;
+
+
+ if ((count > 63) || *ppos)
+ return -EFBIG;
+ if (copy_from_user(buffer, buf, count))
+ return -EFAULT;
+ hcppt = simple_strtoul(buffer, &endptr, 0);
+ if ((endptr == buffer) || (hcppt == ULONG_MAX))
+ return -EINVAL;
+
+ if ((res = set_cpu_rate_cap(task, hcppt)) != 0)
+ return res;
+
+ return count;
+}
+
+struct file_operations proc_cpu_rate_cap_operations = {
+ read: cpu_rate_cap_read,
+ write: cpu_rate_cap_write,
+};
+#endif
+
static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
@@ -1803,6 +1857,11 @@ static struct dentry *proc_pident_lookup
inode->i_fop = &proc_loginuid_operations;
break;
#endif
+#ifdef CONFIG_CPU_RATE_CAPS
+ case PROC_TID_CPU_RATE_CAP:
+ inode->i_fop = &proc_cpu_rate_cap_operations;
+ break;
+#endif
default:
printk("procfs: impossible type (%d)",p->type);
iput(inode);
Index: MM-2.6.17-mm1/kernel/Kconfig.caps
===================================================================
--- MM-2.6.17-mm1.orig/kernel/Kconfig.caps 2006-06-22 10:29:46.000000000
+1000
+++ MM-2.6.17-mm1/kernel/Kconfig.caps 2006-06-22 10:48:54.000000000 +1000
@@ -11,6 +11,11 @@ config CPU_RATE_CAPS
allocated a soft CPU rate cap will be limited to that rate of CPU
usage unless there is spare CPU resources available after the needs
of uncapped tasks are met.
+ Task soft caps can be set/got via the procfs file system using
+ files of the form /proc/<tgid>/task/<pid>/cpu_rate_cap in parts
+ per thousand. Minimum soft cap is 0 and effectively places the
+ task in the background. Maximum soft cap is 1000 and means
+ unlimited.
config CPU_RATE_HARD_CAPS
bool "Support CPU rate hard caps"
--
Peter Williams [EMAIL PROTECTED]
"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
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