This patch series completes the removal of rte_smp_XX barrier
functions that was announced over five years ago (20.05).
In the process several race conditions were found and fixed. See
patches 3, 4 and 17, marked with Fixes: and Cc: stable. Patch 2 is
also marked for stable because 3 and 4 do not build with clang
without it.
Most of this is mechanical with AI assistance, so strongly encourage
maintainers to take a good look.
Barriers ordering memory writes against a device doorbell now use
rte_io_wmb() rather than an SMP barrier; on arm64 that is dmb oshst
instead of dmb ishst. In some cases the C11 form gives marginal
performance gains.
The lock-free stack patch measured faster than the generic version it
replaces, up to 63% on a 32-core x86 box; the numbers are in that
patch's commit message.
Patch 19 keeps the Peterson lock test, converted to C11 atomics, with
the seq_cst fence and rte_mb() as its two cases. It comes before
patch 20, which holds the last rte_smp_mb() caller, so x86 builds
with tests enabled stay bisectable. Tested on x86, arm and riscv;
still untested on ppc and loongarch.
Patch 18 has no ack. Bruce, yours landed on 17; 18 changed since.
Left for follow-up: device read barriers in patches 6, 8 and 14 are
acquire fences where rte_io_rmb() would match the write side (same
generated code today, so no regression). And the net/thunderx mailbox
flags in patch 10 are plain bitfields that need to be atomic, which
is pre-existing.
v4 - rebase on main, which obsoleted the netvsc patch; address review
comments from Konstantin, Marat, David and Wei Hu; collect tags
Stephen Hemminger (29):
bpf: replace deprecated SMP barriers with C11 fences
bus/vmbus: remove packed attribute from ring buffer
bus/vmbus: fix ring buffer ordering on weakly ordered CPUs
bus/vmbus: fix missing acquire on receive ring index
bus/vmbus: replace SMP barriers with C11 memory fences
drivers/baseband: convert rte_smp_rmb to fence
net/hinic: replace rte_smp_rmb
net/intel: replace rte_smp_rmb
net/virtio: replace rte_smp_rmb
net/thunderx: replace deprecated SMP barriers
stack: always use C11 memory model implementation
ring: replace SMP read barrier with C11 acquire fence
crypto/virtio: update comment reference to rte_smp_rmb
crypto/caam_jr: replace rte_smp_rmb
crypto/caam_jr: use IO barrier before job ring doorbell
crypto/octeontx: use IO barrier before doorbell
event/sw: fix unlinks in progress counter races
event/sw: replace SMP barriers with C11 atomics
test/barrier: convert to C11 atomics
eal/x86: move optimized fence out of SMP barrier
common/octeontx: remove redundant barrier in mbox
mempool/octeontx: use IO barrier in pool destroy
event/octeontx: replace deprecated SMP barriers
event/dpaa2: replace deprecated barrier in selftest
event/dsw: replace SMP barriers with release fences
event/opdl: replace SMP barriers with C11 atomics
net/virtio: replace deprecated barrier in avail index update
eal: remove stale SMP barrier in rte_service
eal: remove rte_smp_XX
app/test/test_barrier.c | 71 ++++----
devtools/checkpatches.sh | 8 -
doc/guides/rel_notes/deprecation.rst | 8 -
doc/guides/rel_notes/release_26_11.rst | 11 ++
.../fpga_5gnr_fec/rte_fpga_5gnr_fec.c | 8 +-
drivers/baseband/fpga_lte_fec/fpga_lte_fec.c | 12 +-
drivers/bus/vmbus/private.h | 12 +-
drivers/bus/vmbus/rte_vmbus_reg.h | 4 +-
drivers/bus/vmbus/vmbus_bufring.c | 22 +--
drivers/bus/vmbus/vmbus_channel.c | 13 +-
drivers/common/octeontx/octeontx_mbox.c | 6 +-
drivers/crypto/caam_jr/caam_jr.c | 5 +-
.../crypto/octeontx/otx_cryptodev_hw_access.h | 4 +-
drivers/crypto/virtio/virtqueue.h | 8 +-
drivers/event/dpaa2/dpaa2_eventdev_selftest.c | 4 +-
drivers/event/dsw/dsw_event.c | 8 +-
drivers/event/octeontx/ssovf_evdev_selftest.c | 6 +-
drivers/event/octeontx/ssovf_worker.c | 8 +-
drivers/event/opdl/opdl_evdev.c | 8 +-
drivers/event/sw/sw_evdev.c | 37 +++--
drivers/event/sw/sw_evdev.h | 11 +-
drivers/event/sw/sw_evdev_scheduler.c | 24 ++-
drivers/mempool/octeontx/octeontx_fpavf.c | 4 +-
drivers/net/hinic/base/hinic_pmd_cmdq.c | 3 +-
drivers/net/hinic/base/hinic_pmd_mgmt.c | 2 +-
drivers/net/intel/ice/ice_rxtx.c | 2 +-
drivers/net/intel/ixgbe/ixgbe_rxtx.c | 2 +-
drivers/net/thunderx/base/nicvf_hw.c | 3 +-
drivers/net/thunderx/base/nicvf_plat.h | 5 +-
drivers/net/virtio/virtqueue.h | 22 +--
lib/bpf/bpf_pkt.c | 26 +--
lib/eal/arm/include/rte_atomic_32.h | 6 -
lib/eal/arm/include/rte_atomic_64.h | 6 -
lib/eal/common/rte_service.c | 1 -
lib/eal/include/generic/rte_atomic.h | 61 -------
lib/eal/loongarch/include/rte_atomic.h | 6 -
lib/eal/ppc/include/rte_atomic.h | 6 -
lib/eal/riscv/include/rte_atomic.h | 6 -
lib/eal/x86/include/rte_atomic.h | 41 ++---
lib/ring/rte_ring_gcc_pvt.h | 6 +-
lib/stack/meson.build | 1 -
lib/stack/rte_stack_lf.h | 4 -
lib/stack/rte_stack_lf_generic.h | 153 ------------------
43 files changed, 226 insertions(+), 438 deletions(-)
delete mode 100644 lib/stack/rte_stack_lf_generic.h
--
2.53.0
