On 05-May-20 4:01 PM, Bruce Richardson wrote:
On Tue, May 05, 2020 at 02:24:07PM +0000, Anatoly Burakov wrote:
Currently, in order to perform a memzone lookup and create/free
the memzone, the user has to call two API's, creating a race
condition. This is particularly destructive for memzone_free call
because the reference provided to memzone_free at the time of call
may be stale or refer to a different memzone altogether.
Fix this race condition by adding an API to perform lookup and
create/free memzone in one go.
Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
lib/librte_eal/common/eal_common_memzone.c | 125 ++++++++---
lib/librte_eal/include/rte_memzone.h | 235 +++++++++++++++++++++
lib/librte_eal/rte_eal_version.map | 4 +
3 files changed, 340 insertions(+), 24 deletions(-)
While I agree that there is a race, is this really a problem in the real
world? Do we really need to expand the number of APIs for allocating memory
further?
I'm not sure how much of a problem it is, hence why this is an RFC
rather than a full blown patch :) as in, "i've identified a race, do we
care?" kind of proposition.
If we really do need the ability to do lookup and create in one, rather
than adding new APIs can we not just add another flag to the existing
rte_memzone_reserve call?
That's a good idea for memzone_reserve(), but it wouldn't work for
memzone_free().
--
Thanks,
Anatoly
