[PATCH] doc/eal: add signal safety warning

[fengchengwen]

On 2022/6/11 7:42, Tyler Retzlaff wrote:
> On Fri, Jun 10, 2022 at 08:23:43AM -0700, Stephen Hemminger wrote:
>> The DPDK is not designed to be used from a signal handler.
>> Add a notice in the documentation describing this limitation,
>> similar to Linux signal-safety manual page.
>>
>> Bugzilla ID: 1030
>> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> 
> Acked-by: Tyler Retzlaff <roretzla at linux.microsoft.com>

Acked-by: Chengwen Feng <fengchengwen at huawei.com>

> 
>> ---
>>  doc/guides/prog_guide/env_abstraction_layer.rst | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
>> index 5f0748fba1c0..36ab4b5ba9b6 100644
>> --- a/doc/guides/prog_guide/env_abstraction_layer.rst
>> +++ b/doc/guides/prog_guide/env_abstraction_layer.rst
>> @@ -732,6 +732,19 @@ controlled with tools like taskset (Linux) or cpuset (FreeBSD),
>>  - with affinity restricted to 2-3, the Control Threads will end up on
>>    CPU 2 (main lcore, which is the default when no CPU is available).
>>  
>> +Signal Safety
>> +~~~~~~~~~~~~~
>> +
>> +The DPDK functions in general can not be safely called from a signal handler.
>> +Most functions are not async-signal-safe because they can acquire locks
>> +and other resources that make them nonrentrant.
>> +
>> +To avoid problems with unsafe functions, can be avoided if required
>> +signals are blocked and a mechanism such as signalfd (Linux) is used
>> +to convert the asynchronous signals into messages that are processed
>> +by a EAL thread.
>> +
>> +
>>  .. _known_issue_label:
>>  
>>  Known Issues
>> -- 
>> 2.35.1
> 
> .
>