Re: [dpdk-dev] [PATCH v3] timer: fix resource leak in finalize

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 05-Jun-19 10:33 AM, Thomas Monjalon wrote:
> 09/05/2019 10:29, Burakov, Anatoly:
>> On 08-May-19 11:35 PM, Erik Gabriel Carrillo wrote:
>>> By using a lock added to the rte_mem_config (which lives in shared
>>> memory), we can synchronize multiple processes in init/finalize and
>>> safely free allocations made during init.
>>>
>>> Signed-off-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
>>> ---
>>> changes in v3:
>>>    - The previous version had race condition.  This version fixes the race
>>>      by adding a lock in shared memory outside of the DPDK heap area
>>>      that can be used to safely free the memzone reserved in the subsystem
>>>      init call. (Anatoly)
>>>
>>>      This patch depends on http://patches.dpdk.org/patch/53333/.
>>>    
>>> changes in v2:
>>>    - Handle scenario where primary process exits before secondaries such
>>>      that memzone is not freed early (Anatoly)
>>>
>>>    lib/librte_eal/common/include/rte_eal_memconfig.h |  3 +++
>>>    lib/librte_timer/rte_timer.c                      | 23 ++++++++++++++++++++++-
>>>    2 files changed, 25 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/librte_eal/common/include/rte_eal_memconfig.h b/lib/librte_eal/common/include/rte_eal_memconfig.h
>>> index 84aabe3..8cbc09c 100644
>>> --- a/lib/librte_eal/common/include/rte_eal_memconfig.h
>>> +++ b/lib/librte_eal/common/include/rte_eal_memconfig.h
>>> @@ -64,6 +64,9 @@ struct rte_mem_config {
>>>    	rte_rwlock_t memory_hotplug_lock;
>>>    	/**< indicates whether memory hotplug request is in progress. */
>>>    
>>> +	rte_spinlock_t timer_subsystem_lock;
>>> +	/**< indicates whether timer subsystem init/finalize is in progress. */
>>> +
>>
>> I believe there's an initialize function somewhere which will initialize
>> all of these locks. This lock should be in there as well.
>>
>> Other than that, i'm OK with this change, however i feel like /just/
>> adding this would be a missed opportunity, because next time we want to
>> add something here it will be an ABI break again.
>>
>> We could perhaps use this opportunity to leave some padding for future
>> data. I'm not sure how would that look like, just an idea floating in my
>> head :)
> 
> Any update or other opinion?
> 

I have a patchset that hides mem config - if we are to add a lock, it 
would be after adding that patch, as a bugfix (since by then it would n 
longer be an ABI breakage or an API change).

-- 
Thanks,
Anatoly