Hi,
On 10/2/24 04:34, Yunsheng Lin wrote:
On 10/1/2024 9:32 PM, Paolo Abeni wrote:
Is the problem only tied to VFs drivers? It's a pity all the page_pool
users will have to pay a bill for it...
I am afraid it is not only tied to VFs drivers, as:
attempting DMA unmaps after the driver has already unbound may leak
resources or at worst corrupt memory.
Unloading PFs driver might cause the above problems too, I guess the
probability of crashing is low for the PF as PF can not be disable
unless it can be hot-unplug'ed, but the probability of leaking resources
behind the dma mapping might be similar.
Out of sheer ignorance, why/how the refcount acquired by the page pool
on the device does not prevent unloading?
I fear the performance impact could be very high: AFICS, if the item
array become fragmented, insertion will take linar time, with the quite
large item_count/pool size. If so, it looks like a no-go.
I fear we should consider blocking the device removal until all the
pages are returned/unmapped ?!? (I hope that could be easier/faster)
/P
