> On 14 Mar 2019, at 07.17, Marcin Dziegielewski > <[email protected]> wrote: > > In some cases write thread migration between cpus can cause > sending writes in improper order and in consequence a lot of > errors from device. > > Write thread affinity to particular cpu prevent before it. > > Signed-off-by: Marcin Dziegielewski <[email protected]> > --- > drivers/lightnvm/pblk-init.c | 30 +++++++++++++++++++++++++++++- > drivers/lightnvm/pblk.h | 1 + > drivers/nvme/host/lightnvm.c | 1 + > include/linux/lightnvm.h | 2 ++ > 4 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c > index 81e8ed4..bd25004 100644 > --- a/drivers/lightnvm/pblk-init.c > +++ b/drivers/lightnvm/pblk-init.c > @@ -21,6 +21,8 @@ > > #include "pblk.h" > #include "pblk-trace.h" > +#include <linux/cpumask.h> > +#include <linux/numa.h> > > static unsigned int write_buffer_size; > > @@ -47,6 +49,8 @@ struct pblk_global_caches { > > struct bio_set pblk_bio_set; > > +cpumask_t free_cpumask; > + > static int pblk_rw_io(struct request_queue *q, struct pblk *pblk, > struct bio *bio) > { > @@ -1098,6 +1102,9 @@ static int pblk_lines_init(struct pblk *pblk) > > static int pblk_writer_init(struct pblk *pblk) > { > + cpumask_t tmp_cpumask, cpumask; > + int cpu; > + > pblk->writer_ts = kthread_create(pblk_write_ts, pblk, "pblk-writer-t"); > if (IS_ERR(pblk->writer_ts)) { > int err = PTR_ERR(pblk->writer_ts); > @@ -1108,6 +1115,22 @@ static int pblk_writer_init(struct pblk *pblk) > return err; > } > > + cpumask_and(&tmp_cpumask, cpumask_of_node(pblk->dev->parent->node), > + cpu_online_mask); > + cpumask_and(&cpumask, &tmp_cpumask, &free_cpumask); > + > + if (!cpumask_weight(&free_cpumask)) { > + free_cpumask = CPU_MASK_ALL; > + cpumask_and(&cpumask, &tmp_cpumask, &free_cpumask); > + } > + > + cpu = cpumask_last(&cpumask); > + > + kthread_bind(pblk->writer_ts, cpu); > + > + cpumask_clear_cpu(cpu, &free_cpumask); > + pblk->writer_cpu = cpu; > + > timer_setup(&pblk->wtimer, pblk_write_timer_fn, 0); > mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(100)); > > @@ -1126,8 +1149,11 @@ static void pblk_writer_stop(struct pblk *pblk) > "Stopping not fully synced write buffer\n"); > > del_timer_sync(&pblk->wtimer); > - if (pblk->writer_ts) > + if (pblk->writer_ts) { > + set_cpus_allowed_ptr(pblk->writer_ts, cpu_online_mask); > kthread_stop(pblk->writer_ts); > + cpumask_set_cpu(pblk->writer_cpu, &free_cpumask); > + } > } > > static void pblk_free(struct pblk *pblk) > @@ -1328,6 +1354,8 @@ static int __init pblk_module_init(void) > { > int ret; > > + free_cpumask = CPU_MASK_ALL; > + > ret = bioset_init(&pblk_bio_set, BIO_POOL_SIZE, 0, 0); > if (ret) > return ret; > diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h > index 381f074..650f983 100644 > --- a/drivers/lightnvm/pblk.h > +++ b/drivers/lightnvm/pblk.h > @@ -690,6 +690,7 @@ struct pblk { > atomic_t inflight_io; /* General inflight I/O counter */ > > struct task_struct *writer_ts; > + int writer_cpu; > > /* Simple translation map of logical addresses to physical addresses. > * The logical addresses is known by the host system, while the physical > diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c > index 949e29e..971a19f 100644 > --- a/drivers/nvme/host/lightnvm.c > +++ b/drivers/nvme/host/lightnvm.c > @@ -982,6 +982,7 @@ int nvme_nvm_register(struct nvme_ns *ns, char > *disk_name, int node) > memcpy(dev->name, disk_name, DISK_NAME_LEN); > dev->ops = &nvme_nvm_dev_ops; > dev->private_data = ns; > + dev->node = node; > ns->ndev = dev; > > return nvm_register(dev); > diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h > index 5d865a5..312029e 100644 > --- a/include/linux/lightnvm.h > +++ b/include/linux/lightnvm.h > @@ -427,6 +427,8 @@ struct nvm_dev { > char name[DISK_NAME_LEN]; > void *private_data; > > + int node; > + > void *rmap; > > struct mutex mlock; > -- > 1.8.3.1
We have a per-CPU semaphore that only allows to send a single I/O in order to prevent write pointer violations. Are you seeing this error, or is it theoretical? Javier
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