Fixup patch, addressing Andrew's review feedback:
Signed-off-by: Kent Overstreet <kmo@xxxxxxxxxxxxx>
---
include/linux/idr.h | 2 +-
lib/idr.c | 38 +++++++++++++++++++++-----------------
2 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/include/linux/idr.h b/include/linux/idr.h
index f0db12b..cdf39be 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -267,7 +267,7 @@ struct percpu_ida {
* will just keep looking - but the bitmap _must_ be set whenever a
* percpu freelist does have tags.
*/
- unsigned long *cpus_have_tags;
+ cpumask_t cpus_have_tags;
struct {
spinlock_t lock;
diff --git a/lib/idr.c b/lib/idr.c
index 26495e1..15c021c 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -1178,7 +1178,13 @@ EXPORT_SYMBOL(ida_init);
#define IDA_PCPU_SIZE ((IDA_PCPU_BATCH_MOVE * 3) / 2)
struct percpu_ida_cpu {
+ /*
+ * Even though this is percpu, we need a lock for tag stealing by remote
+ * CPUs:
+ */
spinlock_t lock;
+
+ /* nr_free/freelist form a stack of free IDs */
unsigned nr_free;
unsigned freelist[];
};
@@ -1209,21 +1215,21 @@ static inline void steal_tags(struct percpu_ida *pool,
unsigned cpus_have_tags, cpu = pool->cpu_last_stolen;
struct percpu_ida_cpu *remote;
- for (cpus_have_tags = bitmap_weight(pool->cpus_have_tags, nr_cpu_ids);
+ for (cpus_have_tags = cpumask_weight(&pool->cpus_have_tags);
cpus_have_tags * IDA_PCPU_SIZE > pool->nr_tags / 2;
cpus_have_tags--) {
- cpu = find_next_bit(pool->cpus_have_tags, nr_cpu_ids, cpu);
+ cpu = cpumask_next(cpu, &pool->cpus_have_tags);
- if (cpu == nr_cpu_ids)
- cpu = find_first_bit(pool->cpus_have_tags, nr_cpu_ids);
+ if (cpu >= nr_cpu_ids)
+ cpu = cpumask_first(&pool->cpus_have_tags);
- if (cpu == nr_cpu_ids)
+ if (cpu >= nr_cpu_ids)
BUG();
pool->cpu_last_stolen = cpu;
remote = per_cpu_ptr(pool->tag_cpu, cpu);
- clear_bit(cpu, pool->cpus_have_tags);
+ cpumask_clear_cpu(cpu, &pool->cpus_have_tags);
if (remote == tags)
continue;
@@ -1246,6 +1252,10 @@ static inline void steal_tags(struct percpu_ida *pool,
}
}
+/*
+ * Pop up to IDA_PCPU_BATCH_MOVE IDs off the global freelist, and push them onto
+ * our percpu freelist:
+ */
static inline void alloc_global_tags(struct percpu_ida *pool,
struct percpu_ida_cpu *tags)
{
@@ -1317,8 +1327,8 @@ int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
if (tags->nr_free) {
tag = tags->freelist[--tags->nr_free];
if (tags->nr_free)
- set_bit(smp_processor_id(),
- pool->cpus_have_tags);
+ cpumask_set_cpu(smp_processor_id(),
+ &pool->cpus_have_tags);
}
spin_unlock(&pool->lock);
@@ -1363,8 +1373,8 @@ void percpu_ida_free(struct percpu_ida *pool, unsigned tag)
spin_unlock(&tags->lock);
if (nr_free == 1) {
- set_bit(smp_processor_id(),
- pool->cpus_have_tags);
+ cpumask_set_cpu(smp_processor_id(),
+ &pool->cpus_have_tags);
wake_up(&pool->wait);
}
@@ -1398,7 +1408,6 @@ EXPORT_SYMBOL_GPL(percpu_ida_free);
void percpu_ida_destroy(struct percpu_ida *pool)
{
free_percpu(pool->tag_cpu);
- kfree(pool->cpus_have_tags);
free_pages((unsigned long) pool->freelist,
get_order(pool->nr_tags * sizeof(unsigned)));
}
@@ -1428,7 +1437,7 @@ int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
/* Guard against overflow */
if (nr_tags > (unsigned) INT_MAX + 1) {
- pr_err("tags.c: nr_tags too large\n");
+ pr_err("percpu_ida_init(): nr_tags too large\n");
return -EINVAL;
}
@@ -1442,11 +1451,6 @@ int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
pool->nr_free = nr_tags;
- pool->cpus_have_tags = kzalloc(BITS_TO_LONGS(nr_cpu_ids) *
- sizeof(unsigned long), GFP_KERNEL);
- if (!pool->cpus_have_tags)
- goto err;
-
pool->tag_cpu = __alloc_percpu(sizeof(struct percpu_ida_cpu) +
IDA_PCPU_SIZE * sizeof(unsigned),
sizeof(unsigned));
--
1.8.4.rc3
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