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seq_file: Add seq_cpumask_list(), seq_nodemask_list()

PATCH In review Lai Jiangshan 3 participants 4 messages Oct 12, 2008 – Oct 16, 2008 VFS

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Lai Jiangshan

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#0 lore raw

PATCH 2/4 seq_file: Add seq_cpumask_list(), seq_nodemask_list()

seq_cpumask_list(), seq_nodemask_list() are very like seq_cpumask(), seq_nodemask(), but they print human readable string.

Signed-off-by Lai Jiangshan <[email protected]>

---

fs/seq_file.c +16 -0
index 11c85fe..eba2eab 100644
@@ -465,6 +465,22 @@ int seq_bitmap(struct seq_file *m, unsigned long *bits, unsigned int nr_bits)
 }
 EXPORT_SYMBOL(seq_bitmap);
 
+int seq_bitmap_list(struct seq_file *m, unsigned long *bits,
+		unsigned int nr_bits)
+{
+	if (m->count < m->size) {
+		int len = bitmap_scnlistprintf(m->buf + m->count,
+				m->size - m->count, bits, nr_bits);
+		if (m->count + len < m->size) {
+			m->count += len;
+			return 0;
+		}
+	}
+	m->count = m->size;
+	return -1;
+}
+EXPORT_SYMBOL(seq_bitmap_list);
+
 static void *single_start(struct seq_file *p, loff_t *pos)
 {
 	return NULL + (*pos == 0);
include/linux/seq_file.h +13 -0
index a1783b2..dc50bcc 100644
@@ -60,6 +60,19 @@ static inline int seq_nodemask(struct seq_file *m, nodemask_t *mask)
 	return seq_bitmap(m, mask->bits, MAX_NUMNODES);
 }
 
+int seq_bitmap_list(struct seq_file *m, unsigned long *bits,
+		unsigned int nr_bits);
+
+static inline int seq_cpumask_list(struct seq_file *m, cpumask_t *mask)
+{
+	return seq_bitmap_list(m, mask->bits, NR_CPUS);
+}
+
+static inline int seq_nodemask_list(struct seq_file *m, nodemask_t *mask)
+{
+	return seq_bitmap_list(m, mask->bits, MAX_NUMNODES);
+}
+
 int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
 int single_release(struct inode *, struct file *);
 void *__seq_open_private(struct file *, const struct seq_operations *, int);
#1 lore raw

include/linux/seq_file.h static inline int seq_nodemask(struct seq_file *m, nodemask_t *mask) · line 69

Quoted 4 lines · On Sun, 12 Oct 2008 17:29:25 +0800 Lai Jiangshan <[email protected]> wrote:
include/linux/seq_file.h +4 -0
+static inline int seq_cpumask_list(struct seq_file *m, cpumask_t *mask)
+{
+	return seq_bitmap_list(m, mask->bits, NR_CPUS);
+}

Is it possible to avoid using NR_CPUS? In some situations it'd be much more efficient to use the runtime-determined max possible cpu index.

But I don't immediately recall how to get at that number. num_possible_cpus() assumes that there are no holes in the CPU identifier list.

#2 lore raw
Quoted 11 lines · Andrew Morton

include/linux/seq_file.h static inline int seq_nodemask(struct seq_file *m, nodemask_t *mask) · line 69

Quoted 4 lines · On Sun, 12 Oct 2008 17:29:25 +0800 Lai Jiangshan <[email protected]> wrote:
include/linux/seq_file.h +4 -0
+static inline int seq_cpumask_list(struct seq_file *m, cpumask_t *mask)
+{
+	return seq_bitmap_list(m, mask->bits, NR_CPUS);
+}

Is it possible to avoid using NR_CPUS? In some situations it'd be much more efficient to use the runtime-determined max possible cpu index.

Quoted 4 lines

But I don't immediately recall how to get at that number. num_possible_cpus() assumes that there are no holes in the CPU identifier list.

nr_cpu_ids represents the max index +1 of the possible cpus. (Usually the same as num_possible_cpus() except a.) it doesn't need to do the cpus_weight() op, and b.) *if* (a big if) the cpu indices are sparse, then they wouldn't be the same values.)

Thanks,
Mike

#3 lore raw
Quoted 17 lines · On Thu, 16 Oct 2008 15:56:30 -0700 Mike Travis <[email protected]> wrote:
Quoted 11 lines · Andrew Morton

include/linux/seq_file.h static inline int seq_nodemask(struct seq_file *m, nodemask_t *mask) · line 69

Quoted 4 lines · On Sun, 12 Oct 2008 17:29:25 +0800 Lai Jiangshan <[email protected]> wrote:
include/linux/seq_file.h +4 -0
+static inline int seq_cpumask_list(struct seq_file *m, cpumask_t *mask)
+{
+	return seq_bitmap_list(m, mask->bits, NR_CPUS);
+}

Is it possible to avoid using NR_CPUS? In some situations it'd be much more efficient to use the runtime-determined max possible cpu index.

Quoted 4 lines

But I don't immediately recall how to get at that number. num_possible_cpus() assumes that there are no holes in the CPU identifier list.

Quoted 4 lines

nr_cpu_ids represents the max index +1 of the possible cpus. (Usually the same as num_possible_cpus() except a.) it doesn't need to do the cpus_weight() op, and b.) *if* (a big if) the cpu indices are sparse, then they wouldn't be the same values.)

OK, thanks. I was foggily looking for max_possible_cpus(), to match num_online_cpus(), num_possible_cpus(), num_present_cpus(). Silly me.