2017-12-18 09:00:20

by Jia-Ju Bai

Subject: [PATCH V2] hyper-v: use GFP_KERNEL for hv_context.hv_numa_map

The kzalloc function is called with GFP_ATOMIC.
But according to driver call graph, it is not in atomic context,
namely no spinlock is held nor in an interrupt handler.

This GFP_ATOMIC is unnecessary, and replace with GFP_KERNEL.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/hv/hv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 8267439..b0d025a 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -150,7 +150,7 @@ int hv_synic_alloc(void)
int cpu;

hv_context.hv_numa_map = kzalloc(sizeof(struct cpumask) * nr_node_ids,
- GFP_ATOMIC);
+ GFP_KERNEL);
if (hv_context.hv_numa_map == NULL) {
pr_err("Unable to allocate NUMA map\n");
goto err;
--
1.7.9.5

2017-12-18 17:05:37

by Stephen Hemminger

Subject: Re: [PATCH V2] hyper-v: use GFP_KERNEL for hv_context.hv_numa_map

On Mon, 18 Dec 2017 17:02:52 +0800
Jia-Ju Bai <[email protected]> wrote:

> The kzalloc function is called with GFP_ATOMIC.
> But according to driver call graph, it is not in atomic context,
> namely no spinlock is held nor in an interrupt handler.
>
> This GFP_ATOMIC is unnecessary, and replace with GFP_KERNEL.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> ---
> drivers/hv/hv.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> index 8267439..b0d025a 100644
> --- a/drivers/hv/hv.c
> +++ b/drivers/hv/hv.c
> @@ -150,7 +150,7 @@ int hv_synic_alloc(void)
> int cpu;
>
> hv_context.hv_numa_map = kzalloc(sizeof(struct cpumask) * nr_node_ids,
> - GFP_ATOMIC);
> + GFP_KERNEL);
> if (hv_context.hv_numa_map == NULL) {
> pr_err("Unable to allocate NUMA map\n");
> goto err;

Thanks, for fixing this.
While you are at it; wouldn't it make sense to use kcalloc here?

2017-12-19 08:41:17

by Jia-Ju Bai

Subject: Re: [PATCH V2] hyper-v: use GFP_KERNEL for hv_context.hv_numa_map

On 2017/12/19 1:05, Stephen Hemminger wrote:
> On Mon, 18 Dec 2017 17:02:52 +0800
> Jia-Ju Bai <[email protected]> wrote:
>
>> The kzalloc function is called with GFP_ATOMIC.
>> But according to driver call graph, it is not in atomic context,
>> namely no spinlock is held nor in an interrupt handler.
>>
>> This GFP_ATOMIC is unnecessary, and replace with GFP_KERNEL.
>>
>> Signed-off-by: Jia-Ju Bai <[email protected]>
>> ---
>> drivers/hv/hv.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
>> index 8267439..b0d025a 100644
>> --- a/drivers/hv/hv.c
>> +++ b/drivers/hv/hv.c
>> @@ -150,7 +150,7 @@ int hv_synic_alloc(void)
>> int cpu;
>>
>> hv_context.hv_numa_map = kzalloc(sizeof(struct cpumask) * nr_node_ids,
>> - GFP_ATOMIC);
>> + GFP_KERNEL);
>> if (hv_context.hv_numa_map == NULL) {
>> pr_err("Unable to allocate NUMA map\n");
>> goto err;
> Thanks, for fixing this.
> While you are at it; wouldn't it make sense to use kcalloc here?

I think kcalloc can be used here.


Thanks,
Jia-Ju Bai