Re: [PATCH 1/2] net: thunderx: Set recevie buffer page usage count in bulk

From: Sunil Kovvuri
Date: Mon Mar 07 2016 - 11:58:51 EST


Hi David,

>> you create a window of time during which the consumer
>> can release the page and prematurely free it.
Okay, but here the consumer i.e HW is notified only after page count
is incremented.
For example if you check 'nicvf_refill_rbdr' fn() only after receive
buffer ring is
refilled with buffers, doorbell is issued to hardware to start using
the new buffers.

So
@@ -241,6 +254,8 @@ refill:
new_rb++;
}

+ nicvf_get_page(nic);
+
calling 'nicvf_get_page' before issuing doorbell ensures page ref
count is properly
set before hw/consumer can use the buffers.

Thanks,
Sunil.