The MM subsystem is trying to reduce struct page to a single pointer.
The first step towards that is splitting struct page by its individual
users, as has already been done with folio and slab. This attempt chooses
'netmem' as a name, but I am not even slightly committed to that name,
and will happily use another.
There are some relatively significant reductions in kernel text
size from these changes. I'm not qualified to judge how they
might affect performance, but every call to put_page() includes
a call to compound_head(), which is now rather more complex
than it once was (at least in a distro config which enables
CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP).
I've only converted one user of the page_pool APIs to use the new netmem
APIs, all the others continue to use the page based ones.
Uh, I see I left netmem_to_virt() as its own commit instead of squashing
it into "netmem: Add utility functions". I'll fix that in the next
version, because I'm sure you'll want some changes anyway.
Happy to answer questions.
Matthew Wilcox (Oracle) (24):
netmem: Create new type
netmem: Add utility functions
page_pool: Add netmem_set_dma_addr() and netmem_get_dma_addr()
page_pool: Convert page_pool_release_page() to
page_pool_release_netmem()
page_pool: Start using netmem in allocation path.
page_pool: Convert page_pool_return_page() to
page_pool_return_netmem()
page_pool: Convert __page_pool_put_page() to __page_pool_put_netmem()
page_pool: Convert pp_alloc_cache to contain netmem
page_pool: Convert page_pool_defrag_page() to
page_pool_defrag_netmem()
page_pool: Convert page_pool_put_defragged_page() to netmem
page_pool: Convert page_pool_empty_ring() to use netmem
page_pool: Convert page_pool_alloc_pages() to page_pool_alloc_netmem()
page_pool: Convert page_pool_dma_sync_for_device() to take a netmem
page_pool: Convert page_pool_recycle_in_cache() to netmem
page_pool: Remove page_pool_defrag_page()
page_pool: Use netmem in page_pool_drain_frag()
page_pool: Convert page_pool_return_skb_page() to use netmem
page_pool: Convert frag_page to frag_nmem
xdp: Convert to netmem
mm: Remove page pool members from struct page
netmem_to_virt
page_pool: Pass a netmem to init_callback()
net: Add support for netmem in skb_frag
mvneta: Convert to netmem
drivers/net/ethernet/marvell/mvneta.c | 48 ++---
include/linux/mm_types.h | 22 ---
include/linux/skbuff.h | 11 ++
include/net/page_pool.h | 181 ++++++++++++++---
include/trace/events/page_pool.h | 28 +--
net/bpf/test_run.c | 4 +-
net/core/page_pool.c | 274 +++++++++++++-------------
net/core/xdp.c | 7 +-
8 files changed, 344 insertions(+), 231 deletions(-)
base-commit: 13ee7ef407cfcf63f4f047460ac5bb6ba5a3447d
--
2.35.1
