* FAILED: patch "[PATCH] IB/hfi1: Avoid hardlockup with flushlist_lock" failed to apply to 4.4-stable tree
@ 2019-06-23 15:58 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2019-06-23 15:58 UTC (permalink / raw)
To: mike.marciniszyn, dennis.dalessandro, dledford, stable; +Cc: stable
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cf131a81967583ae737df6383a0893b9fee75b4e Mon Sep 17 00:00:00 2001
From: Mike Marciniszyn <mike.marciniszyn@intel.com>
Date: Fri, 14 Jun 2019 12:32:26 -0400
Subject: [PATCH] IB/hfi1: Avoid hardlockup with flushlist_lock
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.
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>
diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c
index b0110728f541..70828de7436b 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)
@@ -2413,7 +2410,7 @@ int sdma_send_txreq(struct sdma_engine *sde,
list_add_tail(&tx->list, &sde->flushlist);
spin_unlock(&sde->flushlist_lock);
iowait_inc_wait_count(wait, tx->num_desc);
- schedule_work(&sde->flush_worker);
+ queue_work_on(sde->cpu, system_highpri_wq, &sde->flush_worker);
ret = -ECOMM;
goto unlock;
nodesc:
@@ -2511,7 +2508,7 @@ int sdma_send_txlist(struct sdma_engine *sde, struct iowait_work *wait,
iowait_inc_wait_count(wait, tx->num_desc);
}
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:
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2019-06-23 15:58 FAILED: patch "[PATCH] IB/hfi1: Avoid hardlockup with flushlist_lock" failed to apply to 4.4-stable tree gregkh
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