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[5.4,029/191] dma-debug: add a schedule point in debug_dma_dump_mappings()

Message ID 20200102215833.093514241@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Jan. 2, 2020, 10:05 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 9ff6aa027dbb98755f0265695354f2dd07c0d1ce ]

debug_dma_dump_mappings() can take a lot of cpu cycles :

lpk43:/# time wc -l /sys/kernel/debug/dma-api/dump
163435 /sys/kernel/debug/dma-api/dump

real	0m0.463s
user	0m0.003s
sys	0m0.459s

Let's add a cond_resched() to avoid holding cpu for too long.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/dma/debug.c | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 099002d84f46..4ad74f5987ea 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -420,6 +420,7 @@  void debug_dma_dump_mappings(struct device *dev)
 		}
 
 		spin_unlock_irqrestore(&bucket->lock, flags);
+		cond_resched();
 	}
 }