From: Mike Marciniszyn <mike.marciniszyn@intel.com>
To: stable@vger.kernel.org
Cc: linux-rdma@vger.kernel.org, stable-commits@vger.kernel.org
Subject: [PATCH] IB/hfi1: Avoid hardlockup with flushlist_lock
Date: Mon, 24 Jun 2019 12:14:29 -0400 [thread overview]
Message-ID: <20190624161428.17461.31880.stgit@awfm-01.aw.intel.com> (raw)
commit cf131a81967583ae737df6383a0893b9fee75b4e upstream.
Heavy contention of the sde flushlist_lock can cause hard lockups at
extreme scale when the flushing logic is under stress.
Mitigate by replacing the item at a time copy to the local list with
an O(1) list_splice_init() and using the high priority work queue to
do the flushes.
Ported to linux-4.14.y.
Fixes: 7724105686e7 ("IB/hfi1: add driver files")
Cc: <stable@vger.kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
---
drivers/infiniband/hw/hfi1/sdma.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c
index 6781bcd..ec613d5 100644
--- a/drivers/infiniband/hw/hfi1/sdma.c
+++ b/drivers/infiniband/hw/hfi1/sdma.c
@@ -410,10 +410,7 @@ static void sdma_flush(struct sdma_engine *sde)
sdma_flush_descq(sde);
spin_lock_irqsave(&sde->flushlist_lock, flags);
/* copy flush list */
- list_for_each_entry_safe(txp, txp_next, &sde->flushlist, list) {
- list_del_init(&txp->list);
- list_add_tail(&txp->list, &flushlist);
- }
+ list_splice_init(&sde->flushlist, &flushlist);
spin_unlock_irqrestore(&sde->flushlist_lock, flags);
/* flush from flush list */
list_for_each_entry_safe(txp, txp_next, &flushlist, list)
@@ -2437,7 +2434,7 @@ int sdma_send_txreq(struct sdma_engine *sde,
wait->tx_count++;
wait->count += tx->num_desc;
}
- schedule_work(&sde->flush_worker);
+ queue_work_on(sde->cpu, system_highpri_wq, &sde->flush_worker);
ret = -ECOMM;
goto unlock;
nodesc:
@@ -2537,7 +2534,7 @@ int sdma_send_txlist(struct sdma_engine *sde, struct iowait *wait,
}
}
spin_unlock(&sde->flushlist_lock);
- schedule_work(&sde->flush_worker);
+ queue_work_on(sde->cpu, system_highpri_wq, &sde->flush_worker);
ret = -ECOMM;
goto update_tail;
nodesc:
next reply other threads:[~2019-06-24 16:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 16:14 Mike Marciniszyn [this message]
2019-06-24 20:17 ` [PATCH] IB/hfi1: Avoid hardlockup with flushlist_lock Sasha Levin
-- strict thread matches above, loose matches on Subject: below --
2019-06-24 16:26 Mike Marciniszyn
2019-06-24 15:56 Mike Marciniszyn
2019-06-24 20:17 ` Sasha Levin
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