Currently there are three implementations for page frag:
1. mm/page_alloc.c: net stack seems to be using it in the
rx part with 'struct page_frag_cache' and the main API
being page_frag_alloc_align().
2. net/core/sock.c: net stack seems to be using it in the
tx part with 'struct page_frag' and the main API being
skb_page_frag_refill().
3. drivers/vhost/net.c: vhost seems to be using it to build
xdp frame, and it's implementation seems to be a mix of
the above two.
This patchset tries to unfiy the page frag implementation a
little bit by unifying gfp bit for order 3 page allocation
and replacing page frag implementation in vhost.c with the
one in page_alloc.c.
After this patchset, we are not only able to unify the page
frag implementation a little, but also able to have about
0.5% performance boost testing by using the vhost_net_test
introduced in the last patch.
Before this patchset:
Performance counter stats for './vhost_net_test' (10 runs):
305325.78 msec task-clock # 1.738 CPUs utilized ( +- 0.12% )
1048668 context-switches # 3.435 K/sec ( +- 0.00% )
11 cpu-migrations # 0.036 /sec ( +- 17.64% )
33 page-faults # 0.108 /sec ( +- 0.49% )
244651819491 cycles # 0.801 GHz ( +- 0.43% ) (64)
64714638024 stalled-cycles-frontend # 26.45% frontend cycles idle ( +- 2.19% ) (67)
30774313491 stalled-cycles-backend # 12.58% backend cycles idle ( +- 7.68% ) (70)
201749748680 instructions # 0.82 insn per cycle
# 0.32 stalled cycles per insn ( +- 0.41% ) (66.76%)
65494787909 branches # 214.508 M/sec ( +- 0.35% ) (64)
4284111313 branch-misses # 6.54% of all branches ( +- 0.45% ) (66)
175.699 +- 0.189 seconds time elapsed ( +- 0.11% )
After this patchset:
Performance counter stats for './vhost_net_test' (10 runs):
303974.38 msec task-clock # 1.739 CPUs utilized ( +- 0.14% )
1048807 context-switches # 3.450 K/sec ( +- 0.00% )
14 cpu-migrations # 0.046 /sec ( +- 12.86% )
33 page-faults # 0.109 /sec ( +- 0.46% )
251289376347 cycles # 0.827 GHz ( +- 0.32% ) (60)
67885175415 stalled-cycles-frontend # 27.01% frontend cycles idle ( +- 0.48% ) (63)
27809282600 stalled-cycles-backend # 11.07% backend cycles idle ( +- 0.36% ) (71)
195543234672 instructions # 0.78 insn per cycle
# 0.35 stalled cycles per insn ( +- 0.29% ) (69.04%)
62423183552 branches # 205.357 M/sec ( +- 0.48% ) (67)
4135666632 branch-misses # 6.63% of all branches ( +- 0.63% ) (67)
174.764 +- 0.214 seconds time elapsed ( +- 0.12% )
Changelog:
V5: Address the comment from jason in vhost_net_test.c and the
comment about leaving out the gfp change for page frag in
sock.c as suggested by Paolo.
V4: Resend based on latest net-next branch.
V3:
1. Add __page_frag_alloc_align() which is passed with the align mask
the original function expected as suggested by Alexander.
2. Drop patch 3 in v2 suggested by Alexander.
3. Reorder patch 4 & 5 in v2 suggested by Alexander.
Note that placing this gfp flags handing for order 3 page in an inline
function is not considered, as we may be able to unify the page_frag
and page_frag_cache handling.
V2: Change 'xor'd' to 'masked off', add vhost tx testing for
vhost_net_test.
V1: Fix some typo, drop RFC tag and rebase on latest net-next.
Yunsheng Lin (5):
mm/page_alloc: modify page_frag_alloc_align() to accept align as an
argument
page_frag: unify gfp bits for order 3 page allocation
net: introduce page_frag_cache_drain()
vhost/net: remove vhost_net_page_frag_refill()
tools: virtio: introduce vhost_net_test
drivers/net/ethernet/google/gve/gve_main.c | 11 +-
drivers/net/ethernet/mediatek/mtk_wed_wo.c | 17 +-
drivers/nvme/host/tcp.c | 7 +-
drivers/nvme/target/tcp.c | 4 +-
drivers/vhost/net.c | 91 ++--
include/linux/gfp.h | 16 +-
mm/page_alloc.c | 22 +-
net/core/skbuff.c | 9 +-
tools/virtio/.gitignore | 1 +
tools/virtio/Makefile | 8 +-
tools/virtio/linux/virtio_config.h | 4 +
tools/virtio/vhost_net_test.c | 536 +++++++++++++++++++++
12 files changed, 613 insertions(+), 113 deletions(-)
create mode 100644 tools/virtio/vhost_net_test.c
--
2.33.0