2012-11-13 01:52:15

by Shan Wei

Subject: [PATCH v4 2/9] net: rds: use this_cpu_* per-cpu helper

From: Shan Wei <[email protected]>


Signed-off-by: Shan Wei <[email protected]>
Reviewed-by: Christoph Lameter <[email protected]>
---
v4:
1. add missing __percpu annotations.
2. [read|write]ing fields of struct rds_ib_cache_head
using __this_cpu_* operation, drop per_cpu_ptr.
---
net/rds/ib.h | 2 +-
net/rds/ib_recv.c | 24 +++++++++++++-----------
2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/net/rds/ib.h b/net/rds/ib.h
index 8d2b3d5..7280ab8 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -50,7 +50,7 @@ struct rds_ib_cache_head {
};

struct rds_ib_refill_cache {
- struct rds_ib_cache_head *percpu;
+ struct rds_ib_cache_head __percpu *percpu;
struct list_head *xfer;
struct list_head *ready;
};
diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 8d19491..8c5bc85 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -418,20 +418,21 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
struct rds_ib_refill_cache *cache)
{
unsigned long flags;
- struct rds_ib_cache_head *chp;
struct list_head *old;
+ struct list_head __percpu *chpfirst;

local_irq_save(flags);

- chp = per_cpu_ptr(cache->percpu, smp_processor_id());
- if (!chp->first)
+ chpfirst = __this_cpu_read(cache->percpu->first);
+ if (!chpfirst)
INIT_LIST_HEAD(new_item);
else /* put on front */
- list_add_tail(new_item, chp->first);
- chp->first = new_item;
- chp->count++;
+ list_add_tail(new_item, chpfirst);

- if (chp->count < RDS_IB_RECYCLE_BATCH_COUNT)
+ __this_cpu_write(chpfirst, new_item);
+ __this_cpu_inc(cache->percpu->count);
+
+ if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
goto end;

/*
@@ -443,12 +444,13 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
do {
old = xchg(&cache->xfer, NULL);
if (old)
- list_splice_entire_tail(old, chp->first);
- old = cmpxchg(&cache->xfer, NULL, chp->first);
+ list_splice_entire_tail(old, chpfirst);
+ old = cmpxchg(&cache->xfer, NULL, chpfirst);
} while (old);

- chp->first = NULL;
- chp->count = 0;
+
+ __this_cpu_write(chpfirst, NULL);
+ __this_cpu_write(cache->percpu->count, 0);
end:
local_irq_restore(flags);
}
--
1.7.1

2012-11-16 08:38:43

by Shan Wei

Subject: Re: [PATCH v4 2/9] net: rds: use this_cpu_* per-cpu helper

Shan Wei said, at 2012/11/13 9:52:
> From: Shan Wei <[email protected]>
>
>
> Signed-off-by: Shan Wei <[email protected]>
> Reviewed-by: Christoph Lameter <[email protected]>

David Miller, would you like to pick it up to your net-next tree?


> ---
> v4:
> 1. add missing __percpu annotations.
> 2. [read|write]ing fields of struct rds_ib_cache_head
> using __this_cpu_* operation, drop per_cpu_ptr.
> ---
> net/rds/ib.h | 2 +-
> net/rds/ib_recv.c | 24 +++++++++++++-----------
> 2 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/net/rds/ib.h b/net/rds/ib.h
> index 8d2b3d5..7280ab8 100644
> --- a/net/rds/ib.h
> +++ b/net/rds/ib.h
> @@ -50,7 +50,7 @@ struct rds_ib_cache_head {
> };
>
> struct rds_ib_refill_cache {
> - struct rds_ib_cache_head *percpu;
> + struct rds_ib_cache_head __percpu *percpu;
> struct list_head *xfer;
> struct list_head *ready;
> };
> diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
> index 8d19491..8c5bc85 100644
> --- a/net/rds/ib_recv.c
> +++ b/net/rds/ib_recv.c
> @@ -418,20 +418,21 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
> struct rds_ib_refill_cache *cache)
> {
> unsigned long flags;
> - struct rds_ib_cache_head *chp;
> struct list_head *old;
> + struct list_head __percpu *chpfirst;
>
> local_irq_save(flags);
>
> - chp = per_cpu_ptr(cache->percpu, smp_processor_id());
> - if (!chp->first)
> + chpfirst = __this_cpu_read(cache->percpu->first);
> + if (!chpfirst)
> INIT_LIST_HEAD(new_item);
> else /* put on front */
> - list_add_tail(new_item, chp->first);
> - chp->first = new_item;
> - chp->count++;
> + list_add_tail(new_item, chpfirst);
>
> - if (chp->count < RDS_IB_RECYCLE_BATCH_COUNT)
> + __this_cpu_write(chpfirst, new_item);
> + __this_cpu_inc(cache->percpu->count);
> +
> + if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
> goto end;
>
> /*
> @@ -443,12 +444,13 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
> do {
> old = xchg(&cache->xfer, NULL);
> if (old)
> - list_splice_entire_tail(old, chp->first);
> - old = cmpxchg(&cache->xfer, NULL, chp->first);
> + list_splice_entire_tail(old, chpfirst);
> + old = cmpxchg(&cache->xfer, NULL, chpfirst);
> } while (old);
>
> - chp->first = NULL;
> - chp->count = 0;
> +
> + __this_cpu_write(chpfirst, NULL);
> + __this_cpu_write(cache->percpu->count, 0);
> end:
> local_irq_restore(flags);
> }
>

2012-11-20 00:00:33

by David Miller

Subject: Re: [PATCH v4 2/9] net: rds: use this_cpu_* per-cpu helper

From: Shan Wei <[email protected]>
Date: Fri, 16 Nov 2012 16:38:33 +0800

> Shan Wei said, at 2012/11/13 9:52:
>> From: Shan Wei <[email protected]>
>>
>>
>> Signed-off-by: Shan Wei <[email protected]>
>> Reviewed-by: Christoph Lameter <[email protected]>
>
> David Miller, would you like to pick it up to your net-next tree?

Applied.