On 05/01/2023 22.46, Matthew Wilcox (Oracle) wrote:
Convert __page_pool_alloc_page_order() and __page_pool_alloc_pages_slow()
to use netmem internally. This removes a couple of calls
to compound_head() that are hidden inside put_page().
Convert trace_page_pool_state_hold(), page_pool_dma_map() and
page_pool_set_pp_info() to take a netmem argument.
Saves 83 bytes of text in __page_pool_alloc_page_order() and 98 in
__page_pool_alloc_pages_slow() for a total of 181 bytes.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/trace/events/page_pool.h | 14 +++++------
net/core/page_pool.c | 42 +++++++++++++++++---------------
2 files changed, 29 insertions(+), 27 deletions(-)
Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Question below.
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 437241aba5a7..4e985502c569 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
[...]
@@ -421,7 +422,8 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
page = NULL;
}
- /* When page just alloc'ed is should/must have refcnt 1. */
+ /* When page just allocated it should have refcnt 1 (but may have
+ * speculative references) */
return page;
What does it mean page may have speculative references ?
And do I/we need to worry about that for page_pool?
--Jesper
