Date: Fri, 17 Apr 2026 17:35:05 +0000 From: Andrew Gallatin <gallatin@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 52e7958702be - main - iflib: ignore reclaim coalescing when low on tx descriptors Message-ID: <69e26f49.329ea.298f2de3@gitrepo.freebsd.org>
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The branch main has been updated by gallatin: URL: https://cgit.FreeBSD.org/src/commit/?id=52e7958702be469a61a5e3173c20a08fc0721b4d commit 52e7958702be469a61a5e3173c20a08fc0721b4d Author: Andrew Gallatin <gallatin@FreeBSD.org> AuthorDate: 2026-04-17 15:52:36 +0000 Commit: Andrew Gallatin <gallatin@FreeBSD.org> CommitDate: 2026-04-17 17:34:27 +0000 iflib: ignore reclaim coalescing when low on tx descriptors If we are low on TX descriptors, bypass iflib_txq_can_reclaim() and force a reclaim. This is intended to reduce the number of output drops under heavy load when using simple transmit. Differential Revision: https://reviews.freebsd.org/D56339 Sponsored by: Netflix --- sys/net/iflib.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/sys/net/iflib.c b/sys/net/iflib.c index b58544255efd..085b69b62553 100644 --- a/sys/net/iflib.c +++ b/sys/net/iflib.c @@ -703,6 +703,7 @@ static struct mbuf *iflib_fixup_rx(struct mbuf *m); #endif static __inline int iflib_completed_tx_reclaim(iflib_txq_t txq, struct mbuf **m_defer); +static __inline void iflib_completed_tx_reclaim_force(iflib_txq_t txq); static SLIST_HEAD(cpu_offset_list, cpu_offset) cpu_offsets = SLIST_HEAD_INITIALIZER(cpu_offsets); @@ -3600,7 +3601,7 @@ defrag: * cxgb */ if (__predict_false(nsegs > TXQ_AVAIL(txq))) { - (void)iflib_completed_tx_reclaim(txq, NULL); + iflib_completed_tx_reclaim_force(txq); if (__predict_false(nsegs > TXQ_AVAIL(txq))) { txq->ift_no_desc_avail++; bus_dmamap_unload(buf_tag, map); @@ -3789,6 +3790,20 @@ iflib_completed_tx_reclaim(iflib_txq_t txq, struct mbuf **m_defer) return (reclaim); } +/* + * Reclaim any transmit descriptors possible, ignoring coalescing + */ +static __inline void +iflib_completed_tx_reclaim_force(iflib_txq_t txq) +{ + int reclaim; + + iflib_tx_credits_update(txq->ift_ctx, txq); + reclaim = DESC_RECLAIMABLE(txq); + if (reclaim != 0) + _iflib_completed_tx_reclaim(txq, NULL, reclaim); +} + static struct mbuf ** _ring_peek_one(struct ifmp_ring *r, int cidx, int offset, int remaining) {home | help
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