Messages in this thread | | | Date | Mon, 12 Jan 2009 15:59:14 +0300 | From | Evgeniy Polyakov <> | Subject | Re: Data corruption issue with splice() on 2.6.27.10 |
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On Mon, Jan 12, 2009 at 11:56:07PM +1100, Herbert Xu (herbert@gondor.apana.org.au) wrote: > > As a long-term solution this sounds as the best case, but introduces > > quite heavy overhead for the allocators. Right now we allocate > > 1500+shared_info rounded up to the nearest power of the two (2k), but > > then we will either need to have own network allocator (I have one :) or > > allocate PAGE_SIZE+shared_info rounded up to the pwoer of the two (i.e. > > 8k), which is unfeasible. > > No that's not what I was suggesting. The page split model allocates > an skb with a very small head that accomodates only the headers. > All payload is stored in the frags structure. > > For 1500-byte packets, we can manage the payload area efficiently > by dividing each allocated page into 2K chunks. The page will > then be automatically freed once all the 2K chunks on it have been > freed through the page ref count mechanism.
That's the part I referred to as a network own allocator. We can have multiple kmem_caches though for the popular MTUs and round up the requested size otherwise.
-- Evgeniy Polyakov
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