Lo! Just stumbled on this by chance while preparing a updated regression report:
On 19.03.2018 16:49, Sasha Levin wrote: > From: Christoph Hellwig <h...@lst.de> > > [ Upstream commit 84676c1f21e8ff54befe985f4f14dc1edc10046b ] TWIMC: That commit (also reported by autosel for 4.14) triggered a regression in 4.16 reported by Artem Bityutskiy in "regression: SCSI/SATA failure" (https://marc.info/?l=linux-kernel&m=151931128006031 ). There were more discussions about the issue and even a patch that fixed it (https://marc.info/?l=linux-kernel&m=152026091325037 https://marc.info/?l=linux-block&m=152051511802229&w=2 https://marc.info/?l=linux-block&m=152102086831636&w=2 ). But a proper fix has not hit mainline yet afaics. Ciao, Thorsten > Currently we assign managed interrupt vectors to all present CPUs. This > works fine for systems were we only online/offline CPUs. But in case of > systems that support physical CPU hotplug (or the virtualized version of > it) this means the additional CPUs covered for in the ACPI tables or on > the command line are not catered for. To fix this we'd either need to > introduce new hotplug CPU states just for this case, or we can start > assining vectors to possible but not present CPUs. > > Reported-by: Christian Borntraeger <borntrae...@de.ibm.com> > Tested-by: Christian Borntraeger <borntrae...@de.ibm.com> > Tested-by: Stefan Haberland <s...@linux.vnet.ibm.com> > Fixes: 4b855ad37194 ("blk-mq: Create hctx for each present CPU") > Cc: linux-kernel@vger.kernel.org > Cc: Thomas Gleixner <t...@linutronix.de> > Signed-off-by: Christoph Hellwig <h...@lst.de> > Signed-off-by: Jens Axboe <ax...@kernel.dk> > Signed-off-by: Sasha Levin <alexander.le...@microsoft.com> > --- > kernel/irq/affinity.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c > index e12d35108225..a37a3b4b6342 100644 > --- a/kernel/irq/affinity.c > +++ b/kernel/irq/affinity.c > @@ -39,7 +39,7 @@ static void irq_spread_init_one(struct cpumask *irqmsk, > struct cpumask *nmsk, > } > } > > -static cpumask_var_t *alloc_node_to_present_cpumask(void) > +static cpumask_var_t *alloc_node_to_possible_cpumask(void) > { > cpumask_var_t *masks; > int node; > @@ -62,7 +62,7 @@ static cpumask_var_t *alloc_node_to_present_cpumask(void) > return NULL; > } > > -static void free_node_to_present_cpumask(cpumask_var_t *masks) > +static void free_node_to_possible_cpumask(cpumask_var_t *masks) > { > int node; > > @@ -71,22 +71,22 @@ static void free_node_to_present_cpumask(cpumask_var_t > *masks) > kfree(masks); > } > > -static void build_node_to_present_cpumask(cpumask_var_t *masks) > +static void build_node_to_possible_cpumask(cpumask_var_t *masks) > { > int cpu; > > - for_each_present_cpu(cpu) > + for_each_possible_cpu(cpu) > cpumask_set_cpu(cpu, masks[cpu_to_node(cpu)]); > } > > -static int get_nodes_in_cpumask(cpumask_var_t *node_to_present_cpumask, > +static int get_nodes_in_cpumask(cpumask_var_t *node_to_possible_cpumask, > const struct cpumask *mask, nodemask_t *nodemsk) > { > int n, nodes = 0; > > /* Calculate the number of nodes in the supplied affinity mask */ > for_each_node(n) { > - if (cpumask_intersects(mask, node_to_present_cpumask[n])) { > + if (cpumask_intersects(mask, node_to_possible_cpumask[n])) { > node_set(n, *nodemsk); > nodes++; > } > @@ -109,7 +109,7 @@ irq_create_affinity_masks(int nvecs, const struct > irq_affinity *affd) > int last_affv = affv + affd->pre_vectors; > nodemask_t nodemsk = NODE_MASK_NONE; > struct cpumask *masks; > - cpumask_var_t nmsk, *node_to_present_cpumask; > + cpumask_var_t nmsk, *node_to_possible_cpumask; > > /* > * If there aren't any vectors left after applying the pre/post > @@ -125,8 +125,8 @@ irq_create_affinity_masks(int nvecs, const struct > irq_affinity *affd) > if (!masks) > goto out; > > - node_to_present_cpumask = alloc_node_to_present_cpumask(); > - if (!node_to_present_cpumask) > + node_to_possible_cpumask = alloc_node_to_possible_cpumask(); > + if (!node_to_possible_cpumask) > goto out; > > /* Fill out vectors at the beginning that don't need affinity */ > @@ -135,8 +135,8 @@ irq_create_affinity_masks(int nvecs, const struct > irq_affinity *affd) > > /* Stabilize the cpumasks */ > get_online_cpus(); > - build_node_to_present_cpumask(node_to_present_cpumask); > - nodes = get_nodes_in_cpumask(node_to_present_cpumask, cpu_present_mask, > + build_node_to_possible_cpumask(node_to_possible_cpumask); > + nodes = get_nodes_in_cpumask(node_to_possible_cpumask, > cpu_possible_mask, > &nodemsk); > > /* > @@ -146,7 +146,7 @@ irq_create_affinity_masks(int nvecs, const struct > irq_affinity *affd) > if (affv <= nodes) { > for_each_node_mask(n, nodemsk) { > cpumask_copy(masks + curvec, > - node_to_present_cpumask[n]); > + node_to_possible_cpumask[n]); > if (++curvec == last_affv) > break; > } > @@ -160,7 +160,7 @@ irq_create_affinity_masks(int nvecs, const struct > irq_affinity *affd) > vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes; > > /* Get the cpus on this node which are in the mask */ > - cpumask_and(nmsk, cpu_present_mask, node_to_present_cpumask[n]); > + cpumask_and(nmsk, cpu_possible_mask, > node_to_possible_cpumask[n]); > > /* Calculate the number of cpus per vector */ > ncpus = cpumask_weight(nmsk); > @@ -192,7 +192,7 @@ irq_create_affinity_masks(int nvecs, const struct > irq_affinity *affd) > /* Fill out vectors at the end that don't need affinity */ > for (; curvec < nvecs; curvec++) > cpumask_copy(masks + curvec, irq_default_affinity); > - free_node_to_present_cpumask(node_to_present_cpumask); > + free_node_to_possible_cpumask(node_to_possible_cpumask); > out: > free_cpumask_var(nmsk); > return masks; > @@ -214,7 +214,7 @@ int irq_calc_affinity_vectors(int minvec, int maxvec, > const struct irq_affinity > return 0; > > get_online_cpus(); > - ret = min_t(int, cpumask_weight(cpu_present_mask), vecs) + resv; > + ret = min_t(int, cpumask_weight(cpu_possible_mask), vecs) + resv; > put_online_cpus(); > return ret; > } >
