BugLink: http://bugs.launchpad.net/bugs/1759723
This patch figures out the final selected CPU, then writes
it to hctx->next_cpu once, then we can avoid to intermediate
next cpu observed from other dispatch paths.
Cc: Stefan Haberland <sth@linux.vnet.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit
476f8c98a9bccccbb97866974ffc80879adf2bbb)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
{
bool tried = false;
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
{
bool tried = false;
+ int next_cpu = hctx->next_cpu;
if (hctx->queue->nr_hw_queues == 1)
return WORK_CPU_UNBOUND;
if (--hctx->next_cpu_batch <= 0) {
if (hctx->queue->nr_hw_queues == 1)
return WORK_CPU_UNBOUND;
if (--hctx->next_cpu_batch <= 0) {
- next_cpu = cpumask_next_and(hctx->next_cpu, hctx->cpumask,
+ next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
cpu_online_mask);
if (next_cpu >= nr_cpu_ids)
cpu_online_mask);
if (next_cpu >= nr_cpu_ids)
- next_cpu = cpumask_first_and(hctx->cpumask,cpu_online_mask);
+ next_cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
/*
* No online CPU is found, so have to make sure hctx->next_cpu
* is set correctly for not breaking workqueue.
*/
if (next_cpu >= nr_cpu_ids)
/*
* No online CPU is found, so have to make sure hctx->next_cpu
* is set correctly for not breaking workqueue.
*/
if (next_cpu >= nr_cpu_ids)
- hctx->next_cpu = cpumask_first(hctx->cpumask);
- else
- hctx->next_cpu = next_cpu;
+ next_cpu = cpumask_first(hctx->cpumask);
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
}
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
}
* Do unbound schedule if we can't find a online CPU for this hctx,
* and it should only happen in the path of handling CPU DEAD.
*/
* Do unbound schedule if we can't find a online CPU for this hctx,
* and it should only happen in the path of handling CPU DEAD.
*/
- if (!cpu_online(hctx->next_cpu)) {
+ if (!cpu_online(next_cpu)) {
if (!tried) {
tried = true;
goto select_cpu;
if (!tried) {
tried = true;
goto select_cpu;
* Make sure to re-select CPU next time once after CPUs
* in hctx->cpumask become online again.
*/
* Make sure to re-select CPU next time once after CPUs
* in hctx->cpumask become online again.
*/
+ hctx->next_cpu = next_cpu;
hctx->next_cpu_batch = 1;
return WORK_CPU_UNBOUND;
}
hctx->next_cpu_batch = 1;
return WORK_CPU_UNBOUND;
}
+
+ hctx->next_cpu = next_cpu;
+ return next_cpu;
}
static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
}
static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,