6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei <ming.lei@xxxxxxxxxx> [ Upstream commit 523f1ea76aad9025f9bd5258d77f4406fa9dbe5d ] Map irq vector into group, which allows to abstract the algorithm for a generic use case outside of the interrupt core. Rename irq_build_affinity_masks as group_cpus_evenly, so the API can be reused for blk-mq to make default queue mapping even though irq vectors aren't involved. No functional change, just rename vector as group. Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Jens Axboe <axboe@xxxxxxxxx> Link: https://lore.kernel.org/r/20221227022905.352674-5-ming.lei@xxxxxxxxxx Stable-dep-of: 0263f92fadbb ("lib/group_cpus.c: avoid acquiring cpu hotplug lock in group_cpus_evenly") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- kernel/irq/affinity.c | 242 +++++++++++++++++++++--------------------- 1 file changed, 121 insertions(+), 121 deletions(-) diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c index 00bba1020ecb2..54083331f1bcb 100644 --- a/kernel/irq/affinity.c +++ b/kernel/irq/affinity.c @@ -9,13 +9,13 @@ #include <linux/cpu.h> #include <linux/sort.h> -static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk, - unsigned int cpus_per_vec) +static void grp_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk, + unsigned int cpus_per_grp) { const struct cpumask *siblmsk; int cpu, sibl; - for ( ; cpus_per_vec > 0; ) { + for ( ; cpus_per_grp > 0; ) { cpu = cpumask_first(nmsk); /* Should not happen, but I'm too lazy to think about it */ @@ -24,18 +24,18 @@ static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk, cpumask_clear_cpu(cpu, nmsk); cpumask_set_cpu(cpu, irqmsk); - cpus_per_vec--; + cpus_per_grp--; /* If the cpu has siblings, use them first */ siblmsk = topology_sibling_cpumask(cpu); - for (sibl = -1; cpus_per_vec > 0; ) { + for (sibl = -1; cpus_per_grp > 0; ) { sibl = cpumask_next(sibl, siblmsk); if (sibl >= nr_cpu_ids) break; if (!cpumask_test_and_clear_cpu(sibl, nmsk)) continue; cpumask_set_cpu(sibl, irqmsk); - cpus_per_vec--; + cpus_per_grp--; } } } @@ -95,48 +95,48 @@ static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask, return nodes; } -struct node_vectors { +struct node_groups { unsigned id; union { - unsigned nvectors; + unsigned ngroups; unsigned ncpus; }; }; static int ncpus_cmp_func(const void *l, const void *r) { - const struct node_vectors *ln = l; - const struct node_vectors *rn = r; + const struct node_groups *ln = l; + const struct node_groups *rn = r; return ln->ncpus - rn->ncpus; } /* - * Allocate vector number for each node, so that for each node: + * Allocate group number for each node, so that for each node: * * 1) the allocated number is >= 1 * - * 2) the allocated numbver is <= active CPU number of this node + * 2) the allocated number is <= active CPU number of this node * - * The actual allocated total vectors may be less than @numvecs when - * active total CPU number is less than @numvecs. + * The actual allocated total groups may be less than @numgrps when + * active total CPU number is less than @numgrps. * * Active CPUs means the CPUs in '@cpu_mask AND @node_to_cpumask[]' * for each node. */ -static void alloc_nodes_vectors(unsigned int numvecs, - cpumask_var_t *node_to_cpumask, - const struct cpumask *cpu_mask, - const nodemask_t nodemsk, - struct cpumask *nmsk, - struct node_vectors *node_vectors) +static void alloc_nodes_groups(unsigned int numgrps, + cpumask_var_t *node_to_cpumask, + const struct cpumask *cpu_mask, + const nodemask_t nodemsk, + struct cpumask *nmsk, + struct node_groups *node_groups) { unsigned n, remaining_ncpus = 0; for (n = 0; n < nr_node_ids; n++) { - node_vectors[n].id = n; - node_vectors[n].ncpus = UINT_MAX; + node_groups[n].id = n; + node_groups[n].ncpus = UINT_MAX; } for_each_node_mask(n, nodemsk) { @@ -148,61 +148,61 @@ static void alloc_nodes_vectors(unsigned int numvecs, if (!ncpus) continue; remaining_ncpus += ncpus; - node_vectors[n].ncpus = ncpus; + node_groups[n].ncpus = ncpus; } - numvecs = min_t(unsigned, remaining_ncpus, numvecs); + numgrps = min_t(unsigned, remaining_ncpus, numgrps); - sort(node_vectors, nr_node_ids, sizeof(node_vectors[0]), + sort(node_groups, nr_node_ids, sizeof(node_groups[0]), ncpus_cmp_func, NULL); /* - * Allocate vectors for each node according to the ratio of this - * node's nr_cpus to remaining un-assigned ncpus. 'numvecs' is + * Allocate groups for each node according to the ratio of this + * node's nr_cpus to remaining un-assigned ncpus. 'numgrps' is * bigger than number of active numa nodes. Always start the * allocation from the node with minimized nr_cpus. * * This way guarantees that each active node gets allocated at - * least one vector, and the theory is simple: over-allocation - * is only done when this node is assigned by one vector, so - * other nodes will be allocated >= 1 vector, since 'numvecs' is + * least one group, and the theory is simple: over-allocation + * is only done when this node is assigned by one group, so + * other nodes will be allocated >= 1 groups, since 'numgrps' is * bigger than number of numa nodes. * - * One perfect invariant is that number of allocated vectors for + * One perfect invariant is that number of allocated groups for * each node is <= CPU count of this node: * * 1) suppose there are two nodes: A and B * ncpu(X) is CPU count of node X - * vecs(X) is the vector count allocated to node X via this + * grps(X) is the group count allocated to node X via this * algorithm * * ncpu(A) <= ncpu(B) * ncpu(A) + ncpu(B) = N - * vecs(A) + vecs(B) = V + * grps(A) + grps(B) = G * - * vecs(A) = max(1, round_down(V * ncpu(A) / N)) - * vecs(B) = V - vecs(A) + * grps(A) = max(1, round_down(G * ncpu(A) / N)) + * grps(B) = G - grps(A) * - * both N and V are integer, and 2 <= V <= N, suppose - * V = N - delta, and 0 <= delta <= N - 2 + * both N and G are integer, and 2 <= G <= N, suppose + * G = N - delta, and 0 <= delta <= N - 2 * - * 2) obviously vecs(A) <= ncpu(A) because: + * 2) obviously grps(A) <= ncpu(A) because: * - * if vecs(A) is 1, then vecs(A) <= ncpu(A) given + * if grps(A) is 1, then grps(A) <= ncpu(A) given * ncpu(A) >= 1 * * otherwise, - * vecs(A) <= V * ncpu(A) / N <= ncpu(A), given V <= N + * grps(A) <= G * ncpu(A) / N <= ncpu(A), given G <= N * - * 3) prove how vecs(B) <= ncpu(B): + * 3) prove how grps(B) <= ncpu(B): * - * if round_down(V * ncpu(A) / N) == 0, vecs(B) won't be - * over-allocated, so vecs(B) <= ncpu(B), + * if round_down(G * ncpu(A) / N) == 0, vecs(B) won't be + * over-allocated, so grps(B) <= ncpu(B), * * otherwise: * - * vecs(A) = - * round_down(V * ncpu(A) / N) = + * grps(A) = + * round_down(G * ncpu(A) / N) = * round_down((N - delta) * ncpu(A) / N) = * round_down((N * ncpu(A) - delta * ncpu(A)) / N) >= * round_down((N * ncpu(A) - delta * N) / N) = @@ -210,52 +210,50 @@ static void alloc_nodes_vectors(unsigned int numvecs, * * then: * - * vecs(A) - V >= ncpu(A) - delta - V + * grps(A) - G >= ncpu(A) - delta - G * => - * V - vecs(A) <= V + delta - ncpu(A) + * G - grps(A) <= G + delta - ncpu(A) * => - * vecs(B) <= N - ncpu(A) + * grps(B) <= N - ncpu(A) * => - * vecs(B) <= cpu(B) + * grps(B) <= cpu(B) * * For nodes >= 3, it can be thought as one node and another big * node given that is exactly what this algorithm is implemented, - * and we always re-calculate 'remaining_ncpus' & 'numvecs', and - * finally for each node X: vecs(X) <= ncpu(X). + * and we always re-calculate 'remaining_ncpus' & 'numgrps', and + * finally for each node X: grps(X) <= ncpu(X). * */ for (n = 0; n < nr_node_ids; n++) { - unsigned nvectors, ncpus; + unsigned ngroups, ncpus; - if (node_vectors[n].ncpus == UINT_MAX) + if (node_groups[n].ncpus == UINT_MAX) continue; - WARN_ON_ONCE(numvecs == 0); + WARN_ON_ONCE(numgrps == 0); - ncpus = node_vectors[n].ncpus; - nvectors = max_t(unsigned, 1, - numvecs * ncpus / remaining_ncpus); - WARN_ON_ONCE(nvectors > ncpus); + ncpus = node_groups[n].ncpus; + ngroups = max_t(unsigned, 1, + numgrps * ncpus / remaining_ncpus); + WARN_ON_ONCE(ngroups > ncpus); - node_vectors[n].nvectors = nvectors; + node_groups[n].ngroups = ngroups; remaining_ncpus -= ncpus; - numvecs -= nvectors; + numgrps -= ngroups; } } -static int __irq_build_affinity_masks(unsigned int startvec, - unsigned int numvecs, - cpumask_var_t *node_to_cpumask, - const struct cpumask *cpu_mask, - struct cpumask *nmsk, - struct cpumask *masks) +static int __group_cpus_evenly(unsigned int startgrp, unsigned int numgrps, + cpumask_var_t *node_to_cpumask, + const struct cpumask *cpu_mask, + struct cpumask *nmsk, struct cpumask *masks) { - unsigned int i, n, nodes, cpus_per_vec, extra_vecs, done = 0; - unsigned int last_affv = numvecs; - unsigned int curvec = startvec; + unsigned int i, n, nodes, cpus_per_grp, extra_grps, done = 0; + unsigned int last_grp = numgrps; + unsigned int curgrp = startgrp; nodemask_t nodemsk = NODE_MASK_NONE; - struct node_vectors *node_vectors; + struct node_groups *node_groups; if (cpumask_empty(cpu_mask)) return 0; @@ -264,34 +262,33 @@ static int __irq_build_affinity_masks(unsigned int startvec, /* * If the number of nodes in the mask is greater than or equal the - * number of vectors we just spread the vectors across the nodes. + * number of groups we just spread the groups across the nodes. */ - if (numvecs <= nodes) { + if (numgrps <= nodes) { for_each_node_mask(n, nodemsk) { /* Ensure that only CPUs which are in both masks are set */ cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]); - cpumask_or(&masks[curvec], &masks[curvec], nmsk); - if (++curvec == last_affv) - curvec = 0; + cpumask_or(&masks[curgrp], &masks[curgrp], nmsk); + if (++curgrp == last_grp) + curgrp = 0; } - return numvecs; + return numgrps; } - node_vectors = kcalloc(nr_node_ids, - sizeof(struct node_vectors), + node_groups = kcalloc(nr_node_ids, + sizeof(struct node_groups), GFP_KERNEL); - if (!node_vectors) + if (!node_groups) return -ENOMEM; - /* allocate vector number for each node */ - alloc_nodes_vectors(numvecs, node_to_cpumask, cpu_mask, - nodemsk, nmsk, node_vectors); - + /* allocate group number for each node */ + alloc_nodes_groups(numgrps, node_to_cpumask, cpu_mask, + nodemsk, nmsk, node_groups); for (i = 0; i < nr_node_ids; i++) { unsigned int ncpus, v; - struct node_vectors *nv = &node_vectors[i]; + struct node_groups *nv = &node_groups[i]; - if (nv->nvectors == UINT_MAX) + if (nv->ngroups == UINT_MAX) continue; /* Get the cpus on this node which are in the mask */ @@ -300,44 +297,47 @@ static int __irq_build_affinity_masks(unsigned int startvec, if (!ncpus) continue; - WARN_ON_ONCE(nv->nvectors > ncpus); + WARN_ON_ONCE(nv->ngroups > ncpus); /* Account for rounding errors */ - extra_vecs = ncpus - nv->nvectors * (ncpus / nv->nvectors); + extra_grps = ncpus - nv->ngroups * (ncpus / nv->ngroups); - /* Spread allocated vectors on CPUs of the current node */ - for (v = 0; v < nv->nvectors; v++, curvec++) { - cpus_per_vec = ncpus / nv->nvectors; + /* Spread allocated groups on CPUs of the current node */ + for (v = 0; v < nv->ngroups; v++, curgrp++) { + cpus_per_grp = ncpus / nv->ngroups; - /* Account for extra vectors to compensate rounding errors */ - if (extra_vecs) { - cpus_per_vec++; - --extra_vecs; + /* Account for extra groups to compensate rounding errors */ + if (extra_grps) { + cpus_per_grp++; + --extra_grps; } /* - * wrapping has to be considered given 'startvec' + * wrapping has to be considered given 'startgrp' * may start anywhere */ - if (curvec >= last_affv) - curvec = 0; - irq_spread_init_one(&masks[curvec], nmsk, - cpus_per_vec); + if (curgrp >= last_grp) + curgrp = 0; + grp_spread_init_one(&masks[curgrp], nmsk, + cpus_per_grp); } - done += nv->nvectors; + done += nv->ngroups; } - kfree(node_vectors); + kfree(node_groups); return done; } /* - * build affinity in two stages: - * 1) spread present CPU on these vectors - * 2) spread other possible CPUs on these vectors + * build affinity in two stages for each group, and try to put close CPUs + * in viewpoint of CPU and NUMA locality into same group, and we run + * two-stage grouping: + * + * 1) allocate present CPUs on these groups evenly first + * 2) allocate other possible CPUs on these groups evenly */ -static struct cpumask *irq_build_affinity_masks(unsigned int numvecs) +static struct cpumask *group_cpus_evenly(unsigned int numgrps) { - unsigned int curvec = 0, nr_present = 0, nr_others = 0; + unsigned int curgrp = 0, nr_present = 0, nr_others = 0; cpumask_var_t *node_to_cpumask; cpumask_var_t nmsk, npresmsk; int ret = -ENOMEM; @@ -353,7 +353,7 @@ static struct cpumask *irq_build_affinity_masks(unsigned int numvecs) if (!node_to_cpumask) goto fail_npresmsk; - masks = kcalloc(numvecs, sizeof(*masks), GFP_KERNEL); + masks = kcalloc(numgrps, sizeof(*masks), GFP_KERNEL); if (!masks) goto fail_node_to_cpumask; @@ -361,26 +361,26 @@ static struct cpumask *irq_build_affinity_masks(unsigned int numvecs) cpus_read_lock(); build_node_to_cpumask(node_to_cpumask); - /* Spread on present CPUs starting from affd->pre_vectors */ - ret = __irq_build_affinity_masks(curvec, numvecs, node_to_cpumask, - cpu_present_mask, nmsk, masks); + /* grouping present CPUs first */ + ret = __group_cpus_evenly(curgrp, numgrps, node_to_cpumask, + cpu_present_mask, nmsk, masks); if (ret < 0) goto fail_build_affinity; nr_present = ret; /* - * Spread on non present CPUs starting from the next vector to be - * handled. If the spreading of present CPUs already exhausted the - * vector space, assign the non present CPUs to the already spread - * out vectors. + * Allocate non present CPUs starting from the next group to be + * handled. If the grouping of present CPUs already exhausted the + * group space, assign the non present CPUs to the already + * allocated out groups. */ - if (nr_present >= numvecs) - curvec = 0; + if (nr_present >= numgrps) + curgrp = 0; else - curvec = nr_present; + curgrp = nr_present; cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask); - ret = __irq_build_affinity_masks(curvec, numvecs, node_to_cpumask, - npresmsk, nmsk, masks); + ret = __group_cpus_evenly(curgrp, numgrps, node_to_cpumask, + npresmsk, nmsk, masks); if (ret >= 0) nr_others = ret; @@ -388,7 +388,7 @@ static struct cpumask *irq_build_affinity_masks(unsigned int numvecs) cpus_read_unlock(); if (ret >= 0) - WARN_ON(nr_present + nr_others < numvecs); + WARN_ON(nr_present + nr_others < numgrps); fail_node_to_cpumask: free_node_to_cpumask(node_to_cpumask); @@ -467,7 +467,7 @@ irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd) for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) { unsigned int this_vecs = affd->set_size[i]; int j; - struct cpumask *result = irq_build_affinity_masks(this_vecs); + struct cpumask *result = group_cpus_evenly(this_vecs); if (!result) { kfree(masks); -- 2.43.0
