Messages in this thread | | | From | Alexander Lobakin <> | Subject | [PATCH bpf-next v3 0/4] xdp: recycle Page Pool backed skbs built from XDP frames | Date | Mon, 13 Mar 2023 22:42:56 +0100 |
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Yeah, I still remember that "Who needs cpumap nowadays" (c), but anyway.
__xdp_build_skb_from_frame() missed the moment when the networking stack became able to recycle skb pages backed by a page_pool. This was making e.g. cpumap redirect even less effective than simple %XDP_PASS. veth was also affected in some scenarios. A lot of drivers use skb_mark_for_recycle() already, it's been almost two years and seems like there are no issues in using it in the generic code too. {__,}xdp_release_frame() can be then removed as it losts its last user. Page Pool becomes then zero-alloc (or almost) in the abovementioned cases, too. Other memory type models (who needs them at this point) have no changes.
Some numbers on 1 Xeon Platinum core bombed with 27 Mpps of 64-byte IPv6 UDP, iavf w/XDP[0] (CONFIG_PAGE_POOL_STATS is enabled):
Plain %XDP_PASS on baseline, Page Pool driver:
src cpu Rx drops dst cpu Rx 2.1 Mpps N/A 2.1 Mpps
cpumap redirect (cross-core, w/o leaving its NUMA node) on baseline:
6.8 Mpps 5.0 Mpps 1.8 Mpps
cpumap redirect with skb PP recycling:
7.9 Mpps 5.7 Mpps 2.2 Mpps +22% (from cpumap redir on baseline)
[0] https://github.com/alobakin/linux/commits/iavf-xdp
Alexander Lobakin (4): selftests/bpf: robustify test_xdp_do_redirect with more payload magics net: page_pool, skbuff: make skb_mark_for_recycle() always available xdp: recycle Page Pool backed skbs built from XDP frames xdp: remove unused {__,}xdp_release_frame()
include/linux/skbuff.h | 4 +-- include/net/xdp.h | 29 --------------- net/core/xdp.c | 19 ++-------- .../bpf/progs/test_xdp_do_redirect.c | 36 +++++++++++++------ 4 files changed, 30 insertions(+), 58 deletions(-)
--- From v2[1]: * fix the test_xdp_do_redirect selftest failing after the series: it was relying on that %XDP_PASS frames can't be recycled on veth (BPF CI, Alexei); * explain "w/o leaving its node" in the cover letter (Jesper).
From v1[2]: * make skb_mark_for_recycle() always available, otherwise there are build failures on non-PP systems (kbuild bot); * 'Page Pool' -> 'page_pool' when it's about a page_pool instance, not API (Jesper); * expanded test system info a bit in the cover letter (Jesper).
[1] https://lore.kernel.org/bpf/20230303133232.2546004-1-aleksander.lobakin@intel.com [2] https://lore.kernel.org/bpf/20230301160315.1022488-1-aleksander.lobakin@intel.com -- 2.39.2
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