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| author | David S. Miller <davem@davemloft.net> | 2021-10-18 13:54:41 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-10-18 13:54:41 +0200 |
| commit | f8ba22a14268b432f685fd8463a958a3594b7fb6 (patch) | |
| tree | 6feb3ee12123611d1988813e9e139c4c81280aec /drivers/net | |
| parent | net: make use of helper netif_is_bridge_master() (diff) | |
| parent | net: sched: Remove Qdisc::running sequence counter (diff) | |
| download | linux-f8ba22a14268b432f685fd8463a958a3594b7fb6.tar.xz linux-f8ba22a14268b432f685fd8463a958a3594b7fb6.zip | |
Merge branch 'remove-qdisc-running-counter'
Sebastian Andrzej Siewior says:
====================
Try to simplify the gnet_stats and remove qdisc->running sequence counter.
The first few patches is a follow up to
https://lore.kernel.org/all/20211007175000.2334713-1-bigeasy@linutronix.de/
The remaining patches (#5+) remove the seqcount_t (Qdisc::running) from
the Qdisc. The statistics (Qdisc::bstats and Qdisc::cpu_bstats) use
u64_stats_t and the "running state" is now represented by a bit in
Qdisc::state.
By removing the seqcount_t from Qdisc and decoupling the bstats
statistics from the seqcount_t it is possible to query the statistics
even if the Qdisc is running instead of waiting until it is idle again.
The try-lock like usage of the seqcount_t in qdisc_run_begin() is
problematic on PREEMPT_RT. Inside the qdisc_run_begin/end() qdisc->running
sequence counter write sections, at sch_direct_xmit(), the seqcount write
serialization lock is released then re-acquired. This is fine for !RT, because
the writer is in a BH disabled region and there is a no in-IRQ reader. For RT
though, BH sections are preemptible. The earlier introduced seqcount_LOCKNAME_t
mechanism, which for RT the reader acquires then relesaes the write
serailization lock to avoid infinite spinning if it preempts a seqcount write
section, cannot work: the qdisc->running write serialization lock is already
intermittingly released inside the seqcount write section.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/ethernet/netronome/nfp/abm/qdisc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/ethernet/netronome/nfp/abm/qdisc.c b/drivers/net/ethernet/netronome/nfp/abm/qdisc.c index 2473fb5f75e5..2a5cc64227e9 100644 --- a/drivers/net/ethernet/netronome/nfp/abm/qdisc.c +++ b/drivers/net/ethernet/netronome/nfp/abm/qdisc.c @@ -458,7 +458,7 @@ nfp_abm_qdisc_graft(struct nfp_abm_link *alink, u32 handle, u32 child_handle, static void nfp_abm_stats_calculate(struct nfp_alink_stats *new, struct nfp_alink_stats *old, - struct gnet_stats_basic_packed *bstats, + struct gnet_stats_basic_sync *bstats, struct gnet_stats_queue *qstats) { _bstats_update(bstats, new->tx_bytes - old->tx_bytes, |