On 16-Sep-20 5:32 AM, Kamaraj P wrote:
Hi Anatoly,
We just dump the memory contents when it fails to allocate the memory.
Hi Kamaraj,
Yes, i can see that the memory is fragmented. That's not what i was
asking though, because memory fragmentation is *expected* if you're
using igb_uio. You're not using VFIO and IOVA as VA addressing, so
you're at the mercy of your kernel when it comes to getting
IOVA-contiguous address. We in DPDK cannot do anything about it, because
we don't control which pages we get and what addresses they get
assigned. There's nothing to fix on our side in this situation.
Here are the things you can do to avoid allocation failure in your case:
1) Drop the IOVA-contiguous allocation flag [1]
2) Use legacy mode [2] [3]
3) Switch to using VFIO [4]
4) Use bigger page size
The first point is crucial! Your allocation *wouldn't have failed* if
your code didn't specify for the allocation to require
IOVA-contiguousness. The fact that it has failed means that your
allocation has requested such memory, so it's on you to ensure that
whatever you're allocating, IOVA-contiguousness is *required*. I cannot
decide that for you as it is your code, so it is up to you to figure out
if whatever you're allocating actually requires such memory, or if you
can safely remove this allocation flag from your code.
[1]
http://doc.dpdk.org/api/rte__memzone_8h.html#a3ccbea77ccab608c6e683817a3eb170f
[2]
http://doc.dpdk.org/guides/prog_guide/env_abstraction_layer.html#memory-mapping-discovery-and-memory-reservation
[3] http://doc.dpdk.org/guides/linux_gsg/linux_eal_parameters.html#id3
[4] I understand the requirement for PF driver, but i think support for
PF in VFIO is coming in 20.11 release
--
Thanks,
Anatoly
