Messages in this thread Patch in this message | | | From | Jon Derrick <> | Subject | [PATCH] genirq/affinity: report extra vectors on uneven nodes | Date | Wed, 7 Aug 2019 14:10:51 -0600 |
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The current irq spreading algorithm spreads vectors amongst cpus evenly per node. If a node has more cpus than another node, the extra vectors being spread may not be reported back to the caller.
This is most apparent with the NVMe driver and nr_cpus < vectors, where the underreporting results in the caller's WARN being triggered:
irq_build_affinity_masks() ... if (nr_present < numvecs) WARN_ON(nr_present + nr_others < numvecs);
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> --- kernel/irq/affinity.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c index 4352b08ae48d..9beafb8c7e92 100644 --- a/kernel/irq/affinity.c +++ b/kernel/irq/affinity.c @@ -127,7 +127,8 @@ static int __irq_build_affinity_masks(unsigned int startvec, } for_each_node_mask(n, nodemsk) { - unsigned int ncpus, v, vecs_to_assign, vecs_per_node; + unsigned int ncpus, v, vecs_to_assign, total_vecs_to_assign, + vecs_per_node; /* Spread the vectors per node */ vecs_per_node = (numvecs - (curvec - firstvec)) / nodes; @@ -141,14 +142,16 @@ static int __irq_build_affinity_masks(unsigned int startvec, /* Account for rounding errors */ extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign); + total_vecs_to_assign = vecs_to_assign + extra_vecs; - for (v = 0; curvec < last_affv && v < vecs_to_assign; + for (v = 0; curvec < last_affv && v < total_vecs_to_assign; curvec++, v++) { cpus_per_vec = ncpus / vecs_to_assign; /* Account for extra vectors to compensate rounding errors */ if (extra_vecs) { cpus_per_vec++; + v++; --extra_vecs; } irq_spread_init_one(&masks[curvec].mask, nmsk, -- 2.20.1
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