Re: [PATCH 0/5] Introduce a bulk order-0 page allocator with two in-tree users

On Wed, 10 Mar 2021 10:46:13 +0000 Mel Gorman [off-list ref] wrote:

This series introduces a bulk order-0 page allocator with sunrpc and
the network page pool being the first users.

<scratches head>

Right now, the [0/n] doesn't even tell us that it's a performance
patchset!

The whole point of this patchset appears to appear in the final paragraph
of the final patch's changelog.

: For XDP-redirect workload with 100G mlx5 driver (that use page_pool)
: redirecting xdp_frame packets into a veth, that does XDP_PASS to create
: an SKB from the xdp_frame, which then cannot return the page to the
: page_pool.  In this case, we saw[1] an improvement of 18.8% from using
: the alloc_pages_bulk API (3,677,958 pps -> 4,368,926 pps).

Much more detail on the overall objective and the observed results,
please?

Also, that workload looks awfully corner-casey.  How beneficial is this
work for more general and widely-used operations?

The implementation is not
particularly efficient and the intention is to iron out what the semantics
of the API should have for users. Once the semantics are ironed out, it can
be made more efficient.

And some guesstimates about how much benefit remains to be realized
would be helpful.