2014-04-22 14:51:08

by Alexander Gordeev

Subject: [PATCH RESEND 0/2] percpu_ida: Couple of tweaks

Hello,

The patches are against 3.15-rc2

Cc: Kent Overstreet <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "Nicholas A. Bellinger" <[email protected]>

Alexander Gordeev (2):
percpu_ida: Move waking up waiters out of atomic contexts
percpu_ida: Sanity check initialization parameters

lib/percpu_ida.c | 17 ++++++++++++-----
1 files changed, 12 insertions(+), 5 deletions(-)

--
1.7.7.6

2014-04-22 14:51:18

by Alexander Gordeev

Subject: [PATCH RESEND 1/2] percpu_ida: Move waking up waiters out of atomic contexts

Currently percpu_ida_free() waikes up waiters always with local
interrupts disabled and sometimes with pool->lock held. Yet, it
does not appear there is any reason why it could not be done out
of these atomic contexts.

Signed-off-by: Alexander Gordeev <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "Nicholas A. Bellinger" <[email protected]>
Acked-by: Kent Overstreet <[email protected]>

Signed-off-by: Alexander Gordeev <[email protected]>
---
lib/percpu_ida.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index 93d145e..472ff08 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -221,6 +221,7 @@ void percpu_ida_free(struct percpu_ida *pool, unsigned tag)
struct percpu_ida_cpu *tags;
unsigned long flags;
unsigned nr_free;
+ bool wake_up = false;

BUG_ON(tag >= pool->nr_tags);

@@ -234,9 +235,8 @@ void percpu_ida_free(struct percpu_ida *pool, unsigned tag)
spin_unlock(&tags->lock);

if (nr_free == 1) {
- cpumask_set_cpu(smp_processor_id(),
- &pool->cpus_have_tags);
- wake_up(&pool->wait);
+ cpumask_set_cpu(smp_processor_id(), &pool->cpus_have_tags);
+ wake_up = true;
}

if (nr_free == pool->percpu_max_size) {
@@ -250,13 +250,15 @@ void percpu_ida_free(struct percpu_ida *pool, unsigned tag)
move_tags(pool->freelist, &pool->nr_free,
tags->freelist, &tags->nr_free,
pool->percpu_batch_size);
-
- wake_up(&pool->wait);
+ wake_up = true;
}
spin_unlock(&pool->lock);
}

local_irq_restore(flags);
+
+ if (wake_up)
+ wake_up(&pool->wait);
}
EXPORT_SYMBOL_GPL(percpu_ida_free);

--
1.7.7.6

2014-04-22 14:51:25

by Alexander Gordeev

Subject: [PATCH RESEND 2/2] percpu_ida: Sanity check initialization parameters

Signed-off-by: Alexander Gordeev <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "Nicholas A. Bellinger" <[email protected]>
Acked-by: Kent Overstreet <[email protected]>
---
lib/percpu_ida.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index 472ff08..f474f03 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -293,6 +293,11 @@ int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
{
unsigned i, cpu, order;

+ if (batch_size > max_size)
+ return -ERANGE;
+ if (!batch_size)
+ return -EINVAL;
+
memset(pool, 0, sizeof(*pool));

init_waitqueue_head(&pool->wait);
--
1.7.7.6