Re: [dpdk-dev] [PATCH v6 04/21] mem: do not check for invalid socket ID

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

On 27-Sep-18 2:14 PM, Alejandro Lucero wrote:
> On Thu, Sep 27, 2018 at 11:41 AM Anatoly Burakov <anatoly.burakov@intel.com>
> wrote:
> 
>> We will be assigning "invalid" socket ID's to external heap, and
>> malloc will now be able to verify if a supplied socket ID is in
>> fact a valid one, rendering parameter checks for sockets
>> obsolete.
>>
>> This changes the semantics of what we understand by "socket ID",
>> so document the change in the release notes.
>>
>> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
>> ---
>>   doc/guides/rel_notes/release_18_11.rst     | 7 +++++++
>>   lib/librte_eal/common/eal_common_memzone.c | 8 +++++---
>>   lib/librte_eal/common/malloc_heap.c        | 2 +-
>>   lib/librte_eal/common/rte_malloc.c         | 4 ----
>>   4 files changed, 13 insertions(+), 8 deletions(-)
>>
>> diff --git a/doc/guides/rel_notes/release_18_11.rst
>> b/doc/guides/rel_notes/release_18_11.rst
>> index 5fc71e208..6ee236302 100644
>> --- a/doc/guides/rel_notes/release_18_11.rst
>> +++ b/doc/guides/rel_notes/release_18_11.rst
>> @@ -98,6 +98,13 @@ API Changes
>>       users of memseg-walk-related functions, as they will now have to skip
>>       externally allocated segments in most cases if the intent is to only
>> iterate
>>       over internal DPDK memory.
>> +  - ``socket_id`` parameter across the entire DPDK has gained additional
>> +    meaning, as some socket ID's will now be representing externally
>> allocated
>> +    memory. No changes will be required for existing code as backwards
>> +    compatibility will be kept, and those who do not use this feature
>> will not
>> +    see these extra socket ID's. Any new API's must not check socket ID
>> +    parameters themselves, and must instead leave it to the memory
>> subsystem to
>> +    decide whether socket ID is a valid one.
>>
>>   ABI Changes
>>   -----------
>> diff --git a/lib/librte_eal/common/eal_common_memzone.c
>> b/lib/librte_eal/common/eal_common_memzone.c
>> index 7300fe05d..b7081afbf 100644
>> --- a/lib/librte_eal/common/eal_common_memzone.c
>> +++ b/lib/librte_eal/common/eal_common_memzone.c
>> @@ -120,13 +120,15 @@ memzone_reserve_aligned_thread_unsafe(const char
>> *name, size_t len,
>>                  return NULL;
>>          }
>>
>> -       if ((socket_id != SOCKET_ID_ANY) &&
>> -           (socket_id >= RTE_MAX_NUMA_NODES || socket_id < 0)) {
>> +       if ((socket_id != SOCKET_ID_ANY) && socket_id < 0) {
>>
> 
> Should not it be better to use RTE_MAX_HEAP instead of removing the check?

First of all, maximum number of heaps should not concern the rest of the 
code - this is purely internal detail of rte_malloc.

More importantly, socket ID is completely independent from number of 
heaps. Socket ID is incremented each time a new heap is created, and 
they are not reused. If you create and destroy a heap 100 times - you'll 
get 100 different socket ID's, even though max number of heaps is less 
than that.

> 
> 
> 
>>                  rte_errno = EINVAL;
>>                  return NULL;
>>          }
>>
>> -       if (!rte_eal_has_hugepages())
>> +       /* only set socket to SOCKET_ID_ANY if we aren't allocating for an
>> +        * external heap.
>> +        */
>> +       if (!rte_eal_has_hugepages() && socket_id < RTE_MAX_NUMA_NODES)
>>                  socket_id = SOCKET_ID_ANY;
>>
>>          contig = (flags & RTE_MEMZONE_IOVA_CONTIG) != 0;
>> diff --git a/lib/librte_eal/common/malloc_heap.c
>> b/lib/librte_eal/common/malloc_heap.c
>> index 1d1e35708..73e478076 100644
>> --- a/lib/librte_eal/common/malloc_heap.c
>> +++ b/lib/librte_eal/common/malloc_heap.c
>> @@ -647,7 +647,7 @@ malloc_heap_alloc(const char *type, size_t size, int
>> socket_arg,
>>          if (size == 0 || (align && !rte_is_power_of_2(align)))
>>                  return NULL;
>>
>> -       if (!rte_eal_has_hugepages())
>> +       if (!rte_eal_has_hugepages() && socket_arg < RTE_MAX_NUMA_NODES)
>>                  socket_arg = SOCKET_ID_ANY;
>>
>>          if (socket_arg == SOCKET_ID_ANY)
>> diff --git a/lib/librte_eal/common/rte_malloc.c
>> b/lib/librte_eal/common/rte_malloc.c
>> index 73d6df31d..9ba1472c3 100644
>> --- a/lib/librte_eal/common/rte_malloc.c
>> +++ b/lib/librte_eal/common/rte_malloc.c
>> @@ -47,10 +47,6 @@ rte_malloc_socket(const char *type, size_t size,
>> unsigned int align,
>>          if (!rte_eal_has_hugepages())
>>                  socket_arg = SOCKET_ID_ANY;
>>
>> -       /* Check socket parameter */
>> -       if (socket_arg >= RTE_MAX_NUMA_NODES)
>> -               return NULL;
>> -
>>
> 
> Sane than before. Better to keep the sanity check using RTE_MAX_HEAPS.

same as above :)


-- 
Thanks,
Anatoly