On 2023/9/14 23:17, Paolo Abeni wrote:

quoted

--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c

@@ -376,6 +376,14 @@ static void page_pool_set_pp_info(struct page_pool *pool,
 {
 	page->pp = pool;
 	page->pp_magic |= PP_SIGNATURE;
+
+	/* Ensuring all pages have been split into one big frag initially:
+	 * page_pool_set_pp_info() is only called once for every page when it
+	 * is allocated from the page allocator and page_pool_fragment_page()
+	 * is dirtying the same cache line as the page->pp_magic above, so
+	 * the overhead is negligible.
+	 */
+	page_pool_fragment_page(page, 1);
 	if (pool->p.init_callback)
 		pool->p.init_callback(page, pool->p.init_arg);
 }

I think it would be nice backing the above claim with some benchmarks.
(possibly even just a micro-benchmark around the relevant APIs)
and include such info into the changelog message.

Sure, will adjust Jesper's below micro-benchmark to test it:
https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/lib/bench_page_pool_simple.c

Please let me know if there is other better idea to do the
micro-benchmark in your mind, thanks.

Cheers,

Paolo

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