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-rw-r--r--kernel/slow-work-proc.c227
1 files changed, 227 insertions, 0 deletions
diff --git a/kernel/slow-work-proc.c b/kernel/slow-work-proc.c
new file mode 100644
index 00000000000..3988032571f
--- /dev/null
+++ b/kernel/slow-work-proc.c
@@ -0,0 +1,227 @@
+/* Slow work debugging
+ *
+ * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/slow-work.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/seq_file.h>
+#include "slow-work.h"
+
+#define ITERATOR_SHIFT (BITS_PER_LONG - 4)
+#define ITERATOR_SELECTOR (0xfUL << ITERATOR_SHIFT)
+#define ITERATOR_COUNTER (~ITERATOR_SELECTOR)
+
+void slow_work_new_thread_desc(struct slow_work *work, struct seq_file *m)
+{
+ seq_puts(m, "Slow-work: New thread");
+}
+
+/*
+ * Render the time mark field on a work item into a 5-char time with units plus
+ * a space
+ */
+static void slow_work_print_mark(struct seq_file *m, struct slow_work *work)
+{
+ struct timespec now, diff;
+
+ now = CURRENT_TIME;
+ diff = timespec_sub(now, work->mark);
+
+ if (diff.tv_sec < 0)
+ seq_puts(m, " -ve ");
+ else if (diff.tv_sec == 0 && diff.tv_nsec < 1000)
+ seq_printf(m, "%3luns ", diff.tv_nsec);
+ else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000)
+ seq_printf(m, "%3luus ", diff.tv_nsec / 1000);
+ else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000000)
+ seq_printf(m, "%3lums ", diff.tv_nsec / 1000000);
+ else if (diff.tv_sec <= 1)
+ seq_puts(m, " 1s ");
+ else if (diff.tv_sec < 60)
+ seq_printf(m, "%4lus ", diff.tv_sec);
+ else if (diff.tv_sec < 60 * 60)
+ seq_printf(m, "%4lum ", diff.tv_sec / 60);
+ else if (diff.tv_sec < 60 * 60 * 24)
+ seq_printf(m, "%4luh ", diff.tv_sec / 3600);
+ else
+ seq_puts(m, "exces ");
+}
+
+/*
+ * Describe a slow work item for /proc
+ */
+static int slow_work_runqueue_show(struct seq_file *m, void *v)
+{
+ struct slow_work *work;
+ struct list_head *p = v;
+ unsigned long id;
+
+ switch ((unsigned long) v) {
+ case 1:
+ seq_puts(m, "THR PID ITEM ADDR FL MARK DESC\n");
+ return 0;
+ case 2:
+ seq_puts(m, "=== ===== ================ == ===== ==========\n");
+ return 0;
+
+ case 3 ... 3 + SLOW_WORK_THREAD_LIMIT - 1:
+ id = (unsigned long) v - 3;
+
+ read_lock(&slow_work_execs_lock);
+ work = slow_work_execs[id];
+ if (work) {
+ smp_read_barrier_depends();
+
+ seq_printf(m, "%3lu %5d %16p %2lx ",
+ id, slow_work_pids[id], work, work->flags);
+ slow_work_print_mark(m, work);
+
+ if (work->ops->desc)
+ work->ops->desc(work, m);
+ seq_putc(m, '\n');
+ }
+ read_unlock(&slow_work_execs_lock);
+ return 0;
+
+ default:
+ work = list_entry(p, struct slow_work, link);
+ seq_printf(m, "%3s - %16p %2lx ",
+ work->flags & SLOW_WORK_VERY_SLOW ? "vsq" : "sq",
+ work, work->flags);
+ slow_work_print_mark(m, work);
+
+ if (work->ops->desc)
+ work->ops->desc(work, m);
+ seq_putc(m, '\n');
+ return 0;
+ }
+}
+
+/*
+ * map the iterator to a work item
+ */
+static void *slow_work_runqueue_index(struct seq_file *m, loff_t *_pos)
+{
+ struct list_head *p;
+ unsigned long count, id;
+
+ switch (*_pos >> ITERATOR_SHIFT) {
+ case 0x0:
+ if (*_pos == 0)
+ *_pos = 1;
+ if (*_pos < 3)
+ return (void *)(unsigned long) *_pos;
+ if (*_pos < 3 + SLOW_WORK_THREAD_LIMIT)
+ for (id = *_pos - 3;
+ id < SLOW_WORK_THREAD_LIMIT;
+ id++, (*_pos)++)
+ if (slow_work_execs[id])
+ return (void *)(unsigned long) *_pos;
+ *_pos = 0x1UL << ITERATOR_SHIFT;
+
+ case 0x1:
+ count = *_pos & ITERATOR_COUNTER;
+ list_for_each(p, &slow_work_queue) {
+ if (count == 0)
+ return p;
+ count--;
+ }
+ *_pos = 0x2UL << ITERATOR_SHIFT;
+
+ case 0x2:
+ count = *_pos & ITERATOR_COUNTER;
+ list_for_each(p, &vslow_work_queue) {
+ if (count == 0)
+ return p;
+ count--;
+ }
+ *_pos = 0x3UL << ITERATOR_SHIFT;
+
+ default:
+ return NULL;
+ }
+}
+
+/*
+ * set up the iterator to start reading from the first line
+ */
+static void *slow_work_runqueue_start(struct seq_file *m, loff_t *_pos)
+{
+ spin_lock_irq(&slow_work_queue_lock);
+ return slow_work_runqueue_index(m, _pos);
+}
+
+/*
+ * move to the next line
+ */
+static void *slow_work_runqueue_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+ struct list_head *p = v;
+ unsigned long selector = *_pos >> ITERATOR_SHIFT;
+
+ (*_pos)++;
+ switch (selector) {
+ case 0x0:
+ return slow_work_runqueue_index(m, _pos);
+
+ case 0x1:
+ if (*_pos >> ITERATOR_SHIFT == 0x1) {
+ p = p->next;
+ if (p != &slow_work_queue)
+ return p;
+ }
+ *_pos = 0x2UL << ITERATOR_SHIFT;
+ p = &vslow_work_queue;
+
+ case 0x2:
+ if (*_pos >> ITERATOR_SHIFT == 0x2) {
+ p = p->next;
+ if (p != &vslow_work_queue)
+ return p;
+ }
+ *_pos = 0x3UL << ITERATOR_SHIFT;
+
+ default:
+ return NULL;
+ }
+}
+
+/*
+ * clean up after reading
+ */
+static void slow_work_runqueue_stop(struct seq_file *m, void *v)
+{
+ spin_unlock_irq(&slow_work_queue_lock);
+}
+
+static const struct seq_operations slow_work_runqueue_ops = {
+ .start = slow_work_runqueue_start,
+ .stop = slow_work_runqueue_stop,
+ .next = slow_work_runqueue_next,
+ .show = slow_work_runqueue_show,
+};
+
+/*
+ * open "/proc/slow_work_rq" to list queue contents
+ */
+static int slow_work_runqueue_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &slow_work_runqueue_ops);
+}
+
+const struct file_operations slow_work_runqueue_fops = {
+ .owner = THIS_MODULE,
+ .open = slow_work_runqueue_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};