[RFC][PATCH 7/7] UBC: proc interface

[Kirill Korotaev <dev@sw.ru>]

Add proc interface (/proc/user_beancounters) allowing to see current
state (usage/limits/fails for each UB). Implemented via seq files.

Signed-Off-By: Pavel Emelianov <xemul@sw.ru>
Signed-Off-By: Kirill Korotaev <dev@sw.ru>

---
 init/main.c        |    1
 kernel/ub/Makefile |    1
 kernel/ub/proc.c   |  205 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 207 insertions(+)

--- ./init/main.c.ubproc	2006-07-31 18:40:20.000000000 +0400
+++ ./init/main.c	2006-08-03 16:02:19.000000000 +0400
@@ -578,6 +578,7 @@ asmlinkage void __init start_kernel(void
 	page_writeback_init();
 #ifdef CONFIG_PROC_FS
 	proc_root_init();
+	ub_init_proc();
 #endif
 	cpuset_init();
 	taskstats_init_early();
--- ./kernel/ub/Makefile.ubproc	2006-07-31 17:49:05.000000000 +0400
+++ ./kernel/ub/Makefile	2006-08-01 11:08:39.000000000 +0400
@@ -4,3 +4,4 @@ obj-$(CONFIG_USER_RESOURCE) += beancount
 obj-$(CONFIG_USER_RESOURCE) += misc.o
 obj-y += sys.o
 obj-$(CONFIG_USER_RESOURCE) += kmem.o
+obj-$(CONFIG_USER_RESOURCE) += proc.o
--- ./kernel/ub/proc.c.ubproc	2006-08-01 10:22:09.000000000 +0400
+++ ./kernel/ub/proc.c	2006-08-03 15:50:35.000000000 +0400
@@ -0,0 +1,205 @@
+/*
+ *  kernel/ub/proc.c 
+ *
+ *  Copyright (C) 2006 OpenVZ. SWsoft Inc.
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include <ub/beancounter.h>
+
+#ifdef CONFIG_PROC_FS
+
+#if BITS_PER_LONG == 32
+static const char *head_fmt = "%10s %-12s %10s %10s %10s %10s %10s\n";
+static const char *res_fmt = "%10s %-12s %10lu %10lu %10lu %10lu %10lu\n";
+#else
+static const char *head_fmt = "%10s %-12s %20s %20s %20s %20s %20s\n";
+static const char *res_fmt = "%10s %-12s %20lu %20lu %20lu %20lu %20lu\n";
+#endif
+
+static void ub_show_header(struct seq_file *f)
+{
+	seq_printf(f, head_fmt, "uid", "resource",
+			"held", "maxheld", "barrier", "limit", "failcnt");
+}
+
+static void ub_show_res(struct seq_file *f, struct user_beancounter *ub, int r)
+{
+	char ub_uid[64];
+
+	if (r == 0)
+		ub_print_uid(ub, ub_uid, sizeof(ub_uid));
+	else
+		strcpy(ub_uid, "");
+
+	seq_printf(f, res_fmt, ub_uid, ub_rnames[r],
+			ub->ub_parms[r].held,
+			ub->ub_parms[r].maxheld,
+			ub->ub_parms[r].barrier,
+			ub->ub_parms[r].limit,
+			ub->ub_parms[r].failcnt);
+}
+
+static struct ub_seq_struct {
+	unsigned long flags;
+	int slot;
+	struct user_beancounter *ub;
+} ub_seq_ctx;
+
+static int ub_show(struct seq_file *f, void *v)
+{
+	int res;
+
+	for (res = 0; res < UB_RESOURCES; res++)
+		ub_show_res(f, ub_seq_ctx.ub, res);
+	return 0;
+}
+
+static void *ub_start_ctx(struct seq_file *f, unsigned long p, int sub)
+{
+	struct user_beancounter *ub;
+	struct hlist_node *pos;
+	unsigned long flags;
+	int slot;
+
+	if (p == 0)
+		ub_show_header(f);
+
+	spin_lock_irqsave(&ub_hash_lock, flags);
+	ub_seq_ctx.flags = flags;
+
+	for (slot = 0; slot < UB_HASH_SIZE; slot++)
+		hlist_for_each_entry (ub, pos, &ub_hash[slot], hash) {
+			if (!sub && ub->parent != NULL)
+				continue;
+
+			if (p-- == 0) {
+				ub_seq_ctx.ub = ub;
+				ub_seq_ctx.slot = slot;
+				return &ub_seq_ctx;
+			}
+		}
+
+	return NULL;
+}
+
+static void *ub_next_ctx(struct seq_file *f, loff_t *ppos, int sub)
+{
+	struct user_beancounter *ub;
+	struct hlist_node *pos;
+	int slot;
+
+	ub = ub_seq_ctx.ub;
+
+	pos = &ub->hash;
+	hlist_for_each_entry_continue (ub, pos, hash) {
+		if (!sub && ub->parent != NULL)
+			continue;
+
+		ub_seq_ctx.ub = ub;
+		(*ppos)++;
+		return &ub_seq_ctx;
+	}
+
+	for (slot = ub_seq_ctx.slot + 1; slot < UB_HASH_SIZE; slot++)
+		hlist_for_each_entry (ub, pos, &ub_hash[slot], hash) {
+			if (!sub && ub->parent != NULL)
+				continue;
+
+			ub_seq_ctx.ub = ub;
+			ub_seq_ctx.slot = slot;
+			(*ppos)++;
+			return &ub_seq_ctx;
+		}
+
+	return NULL;
+}
+
+static void *ub_start(struct seq_file *f, loff_t *ppos)
+{
+	return ub_start_ctx(f, *ppos, 0);
+}
+
+static void *ub_sub_start(struct seq_file *f, loff_t *ppos)
+{
+	return ub_start_ctx(f, *ppos, 1);
+}
+
+static void *ub_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	return ub_next_ctx(f, pos, 0);
+}
+
+static void *ub_sub_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	return ub_next_ctx(f, pos, 1);
+}
+
+static void ub_stop(struct seq_file *f, void *v)
+{
+	unsigned long flags;
+
+	flags = ub_seq_ctx.flags;
+	spin_unlock_irqrestore(&ub_hash_lock, flags);
+}
+
+static struct seq_operations ub_seq_ops = {
+	.start = ub_start,
+	.next  = ub_next,
+	.stop  = ub_stop,
+	.show  = ub_show
+};
+
+static int ub_open(struct inode *inode, struct file *filp)
+{
+	return seq_open(filp, &ub_seq_ops);
+}
+
+static struct file_operations ub_file_operations = {
+	.open		= ub_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static struct seq_operations ub_sub_seq_ops = {
+	.start = ub_sub_start,
+	.next  = ub_sub_next,
+	.stop  = ub_stop,
+	.show  = ub_show
+};
+
+static int ub_sub_open(struct inode *inode, struct file *filp)
+{
+	return seq_open(filp, &ub_sub_seq_ops);
+}
+
+static struct file_operations ub_sub_file_operations = {
+	.open		= ub_sub_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+void __init ub_init_proc(void)
+{
+	struct proc_dir_entry *entry;
+
+	entry = create_proc_entry("user_beancounters", S_IRUGO, NULL);
+	if (entry)
+		entry->proc_fops = &ub_file_operations;
+	else
+		panic("Can't create /proc/user_beancounters\n");
+
+	entry = create_proc_entry("user_beancounters_sub", S_IRUGO, NULL);
+	if (entry)
+		entry->proc_fops = &ub_sub_file_operations;
+	else
+		panic("Can't create /proc/user_beancounters_sub\n");
+}
+#endif