Hi
Setup: sdm845 connected to external modem over pcie interface
During a data call, we found out we spend more than 25% of cpu for
memory ops with io coherency. That include allocation, freeing, dma
mapping, and unmapping. As we pushing to higher data rate (beyond 7
Gbps), the time we spend in memory operation is significant. So, we're
looking into ways we can reclaim this memory.
One of idea we're thinking is:
1. allocate pages
2. Increment reference count of page
3. allocate skb, and assign page into paged data portion
4. Assign cb function to skb->destructor
5. once destructor get called, move the page to a new skb
Sound simple enough, but we couldn't find anyone actually doing this
way. Anything to be concern with above proposal? We see some example of
using destructor to do deferred unmap but didn't see any example of
re-using the buffer. Also, couldn't find any meaningful discussion about
reclaiming memory for network data. Any thoughts on how we should solve
this issue? Any comment is welcome, thanks.
Sincerely
Sujeev
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