coresight: catu: Fix number of pages while using 64k pages

[PATCH] coresight: catu: Fix number of pages while using 64k pages

Posted by Ilkka Koskinen 11 months, 2 weeks ago

Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
This happens due to a bug in calculating the number of table pages, which
returns zero. Fix the issue by rounding up.

$ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
failed to mmap with 12 (Cannot allocate memory)

Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
---
 drivers/hwtracing/coresight/coresight-catu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
index 275cc0d9f505..3378bb77e6b4 100644
--- a/drivers/hwtracing/coresight/coresight-catu.c
+++ b/drivers/hwtracing/coresight/coresight-catu.c
@@ -269,7 +269,7 @@ catu_init_sg_table(struct device *catu_dev, int node,
 	 * Each table can address upto 1MB and we can have
 	 * CATU_PAGES_PER_SYSPAGE tables in a system page.
 	 */
-	nr_tpages = DIV_ROUND_UP(size, SZ_1M) / CATU_PAGES_PER_SYSPAGE;
+	nr_tpages = DIV_ROUND_UP(size, CATU_PAGES_PER_SYSPAGE * SZ_1M);
 	catu_table = tmc_alloc_sg_table(catu_dev, node, nr_tpages,
 					size >> PAGE_SHIFT, pages);
 	if (IS_ERR(catu_table))
-- 
2.47.0

Re: [PATCH] coresight: catu: Fix number of pages while using 64k pages

Posted by Suzuki K Poulose 10 months ago

On Thu, 9 Jan 2025 21:53:48 +0000, Ilkka Koskinen wrote:
> Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
> This happens due to a bug in calculating the number of table pages, which
> returns zero. Fix the issue by rounding up.
> 
> $ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
> failed to mmap with 12 (Cannot allocate memory)
> 
> [...]

Applied, thanks!

[1/1] coresight: catu: Fix number of pages while using 64k pages
      https://git.kernel.org/coresight/c/0e14e062f5ff

Best regards,
-- 
Suzuki K Poulose <suzuki.poulose@arm.com>

Re: [PATCH] coresight: catu: Fix number of pages while using 64k pages

Posted by Suzuki K Poulose 11 months, 1 week ago

On 09/01/2025 21:53, Ilkka Koskinen wrote:
> Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
> This happens due to a bug in calculating the number of table pages, which
> returns zero. Fix the issue by rounding up.
> 
> $ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
> failed to mmap with 12 (Cannot allocate memory)
> 

Needs a Fixes tag.

Fixes : 8ed536b1e283 ("coresight: catu: Add support for scatter gather 
tables")

> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
> ---
>   drivers/hwtracing/coresight/coresight-catu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
> index 275cc0d9f505..3378bb77e6b4 100644
> --- a/drivers/hwtracing/coresight/coresight-catu.c
> +++ b/drivers/hwtracing/coresight/coresight-catu.c
> @@ -269,7 +269,7 @@ catu_init_sg_table(struct device *catu_dev, int node,
>   	 * Each table can address upto 1MB and we can have
>   	 * CATU_PAGES_PER_SYSPAGE tables in a system page.
>   	 */
> -	nr_tpages = DIV_ROUND_UP(size, SZ_1M) / CATU_PAGES_PER_SYSPAGE;
> +	nr_tpages = DIV_ROUND_UP(size, CATU_PAGES_PER_SYSPAGE * SZ_1M);
>   	catu_table = tmc_alloc_sg_table(catu_dev, node, nr_tpages,
>   					size >> PAGE_SHIFT, pages);
>   	if (IS_ERR(catu_table))

Looks good to me, I will queue this later for v6.15.

Suzuki

Re: [PATCH] coresight: catu: Fix number of pages while using 64k pages

Posted by Ilkka Koskinen 11 months, 1 week ago

Hi Suzuko,

On Fri, 10 Jan 2025, Suzuki K Poulose wrote:
> On 09/01/2025 21:53, Ilkka Koskinen wrote:
>> Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
>> This happens due to a bug in calculating the number of table pages, which
>> returns zero. Fix the issue by rounding up.
>> 
>> $ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k 
>> --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
>> failed to mmap with 12 (Cannot allocate memory)
>> 
>
> Needs a Fixes tag.
>
> Fixes : 8ed536b1e283 ("coresight: catu: Add support for scatter gather 
> tables")

That's a good point

>
>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-catu.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/hwtracing/coresight/coresight-catu.c 
>> b/drivers/hwtracing/coresight/coresight-catu.c
>> index 275cc0d9f505..3378bb77e6b4 100644
>> --- a/drivers/hwtracing/coresight/coresight-catu.c
>> +++ b/drivers/hwtracing/coresight/coresight-catu.c
>> @@ -269,7 +269,7 @@ catu_init_sg_table(struct device *catu_dev, int node,
>>   	 * Each table can address upto 1MB and we can have
>>   	 * CATU_PAGES_PER_SYSPAGE tables in a system page.
>>   	 */
>> -	nr_tpages = DIV_ROUND_UP(size, SZ_1M) / CATU_PAGES_PER_SYSPAGE;
>> +	nr_tpages = DIV_ROUND_UP(size, CATU_PAGES_PER_SYSPAGE * SZ_1M);
>>   	catu_table = tmc_alloc_sg_table(catu_dev, node, nr_tpages,
>>   					size >> PAGE_SHIFT, pages);
>>   	if (IS_ERR(catu_table))
>
> Looks good to me, I will queue this later for v6.15.
>
> Suzuki

Sounds great. Just to confirm, are you ok to add the fixes line or would 
you prefer me to submit v2 with it?

Cheers, Ilkka

Re: [PATCH] coresight: catu: Fix number of pages while using 64k pages

Posted by Suzuki K Poulose 11 months, 1 week ago

On 10/01/2025 21:32, Ilkka Koskinen wrote:
> 
> Hi Suzuko,
> 
> On Fri, 10 Jan 2025, Suzuki K Poulose wrote:
>> On 09/01/2025 21:53, Ilkka Koskinen wrote:
>>> Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
>>> This happens due to a bug in calculating the number of table pages, 
>>> which
>>> returns zero. Fix the issue by rounding up.
>>>
>>> $ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k 
>>> --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
>>> failed to mmap with 12 (Cannot allocate memory)
>>>
>>
>> Needs a Fixes tag.
>>
>> Fixes : 8ed536b1e283 ("coresight: catu: Add support for scatter gather 
>> tables")
> 
> That's a good point
> 
>>
>>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
>>> ---
>>>   drivers/hwtracing/coresight/coresight-catu.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/ 
>>> hwtracing/coresight/coresight-catu.c
>>> index 275cc0d9f505..3378bb77e6b4 100644
>>> --- a/drivers/hwtracing/coresight/coresight-catu.c
>>> +++ b/drivers/hwtracing/coresight/coresight-catu.c
>>> @@ -269,7 +269,7 @@ catu_init_sg_table(struct device *catu_dev, int 
>>> node,
>>>        * Each table can address upto 1MB and we can have
>>>        * CATU_PAGES_PER_SYSPAGE tables in a system page.
>>>        */
>>> -    nr_tpages = DIV_ROUND_UP(size, SZ_1M) / CATU_PAGES_PER_SYSPAGE;
>>> +    nr_tpages = DIV_ROUND_UP(size, CATU_PAGES_PER_SYSPAGE * SZ_1M);
>>>       catu_table = tmc_alloc_sg_table(catu_dev, node, nr_tpages,
>>>                       size >> PAGE_SHIFT, pages);
>>>       if (IS_ERR(catu_table))
>>
>> Looks good to me, I will queue this later for v6.15.
>>
>> Suzuki
> 
> Sounds great. Just to confirm, are you ok to add the fixes line or would 
> you prefer me to submit v2 with it?

No, not required. I have picked this up for v6.15, and will push it out
once v6.14-rc is out.

Suzuki


> 
> Cheers, Ilkka

Re: [PATCH] coresight: catu: Fix number of pages while using 64k pages

Posted by Ilkka Koskinen 11 months, 1 week ago


On Mon, 13 Jan 2025, Suzuki K Poulose wrote:
> On 10/01/2025 21:32, Ilkka Koskinen wrote:
>> 
>> Hi Suzuko,
>> 
>> On Fri, 10 Jan 2025, Suzuki K Poulose wrote:
>>> On 09/01/2025 21:53, Ilkka Koskinen wrote:
>>>> Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
>>>> This happens due to a bug in calculating the number of table pages, which
>>>> returns zero. Fix the issue by rounding up.
>>>> 
>>>> $ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k 
>>>> --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
>>>> failed to mmap with 12 (Cannot allocate memory)
>>>> 
>>> 
>>> Needs a Fixes tag.
>>> 
>>> Fixes : 8ed536b1e283 ("coresight: catu: Add support for scatter gather 
>>> tables")
>> 
>> That's a good point
>> 
>>> 
>>>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
>>>> ---
>>>>   drivers/hwtracing/coresight/coresight-catu.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>> 
>>>> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/ 
>>>> hwtracing/coresight/coresight-catu.c
>>>> index 275cc0d9f505..3378bb77e6b4 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-catu.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-catu.c
>>>> @@ -269,7 +269,7 @@ catu_init_sg_table(struct device *catu_dev, int node,
>>>>        * Each table can address upto 1MB and we can have
>>>>        * CATU_PAGES_PER_SYSPAGE tables in a system page.
>>>>        */
>>>> -    nr_tpages = DIV_ROUND_UP(size, SZ_1M) / CATU_PAGES_PER_SYSPAGE;
>>>> +    nr_tpages = DIV_ROUND_UP(size, CATU_PAGES_PER_SYSPAGE * SZ_1M);
>>>>       catu_table = tmc_alloc_sg_table(catu_dev, node, nr_tpages,
>>>>                       size >> PAGE_SHIFT, pages);
>>>>       if (IS_ERR(catu_table))
>>> 
>>> Looks good to me, I will queue this later for v6.15.
>>> 
>>> Suzuki
>> 
>> Sounds great. Just to confirm, are you ok to add the fixes line or would 
>> you prefer me to submit v2 with it?
>
> No, not required. I have picked this up for v6.15, and will push it out
> once v6.14-rc is out.

Perfect, thanks!

--Ilkka