From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- lib/dim/rdma_dim.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 lib/dim/rdma_dim.c (limited to 'lib/dim/rdma_dim.c') diff --git a/lib/dim/rdma_dim.c b/lib/dim/rdma_dim.c new file mode 100644 index 000000000..88f779486 --- /dev/null +++ b/lib/dim/rdma_dim.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +/* + * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved. + */ + +#include + +static int rdma_dim_step(struct dim *dim) +{ + if (dim->tune_state == DIM_GOING_RIGHT) { + if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1)) + return DIM_ON_EDGE; + dim->profile_ix++; + dim->steps_right++; + } + if (dim->tune_state == DIM_GOING_LEFT) { + if (dim->profile_ix == 0) + return DIM_ON_EDGE; + dim->profile_ix--; + dim->steps_left++; + } + + return DIM_STEPPED; +} + +static int rdma_dim_stats_compare(struct dim_stats *curr, + struct dim_stats *prev) +{ + /* first stat */ + if (!prev->cpms) + return DIM_STATS_SAME; + + if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms)) + return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER : + DIM_STATS_WORSE; + + if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio)) + return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER : + DIM_STATS_WORSE; + + return DIM_STATS_SAME; +} + +static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim) +{ + int prev_ix = dim->profile_ix; + u8 state = dim->tune_state; + int stats_res; + int step_res; + + if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) { + stats_res = rdma_dim_stats_compare(curr_stats, + &dim->prev_stats); + + switch (stats_res) { + case DIM_STATS_SAME: + if (curr_stats->cpe_ratio <= 50 * prev_ix) + dim->profile_ix = 0; + break; + case DIM_STATS_WORSE: + dim_turn(dim); + fallthrough; + case DIM_STATS_BETTER: + step_res = rdma_dim_step(dim); + if (step_res == DIM_ON_EDGE) + dim_turn(dim); + break; + } + } + + dim->prev_stats = *curr_stats; + + return dim->profile_ix != prev_ix; +} + +void rdma_dim(struct dim *dim, u64 completions) +{ + struct dim_sample *curr_sample = &dim->measuring_sample; + struct dim_stats curr_stats; + u32 nevents; + + dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0, + curr_sample->comp_ctr + completions, + &dim->measuring_sample); + + switch (dim->state) { + case DIM_MEASURE_IN_PROGRESS: + nevents = curr_sample->event_ctr - dim->start_sample.event_ctr; + if (nevents < DIM_NEVENTS) + break; + if (!dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats)) + break; + if (rdma_dim_decision(&curr_stats, dim)) { + dim->state = DIM_APPLY_NEW_PROFILE; + schedule_work(&dim->work); + break; + } + fallthrough; + case DIM_START_MEASURE: + dim->state = DIM_MEASURE_IN_PROGRESS; + dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0, + curr_sample->comp_ctr, + &dim->start_sample); + break; + case DIM_APPLY_NEW_PROFILE: + break; + } +} +EXPORT_SYMBOL(rdma_dim); -- cgit v1.3.1