[PATCH] dma-debug: add a schedule point in debug_dma_dump_mappings()

From: Eric Dumazet
Date: Mon Oct 28 2019 - 17:56:54 EST


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@xxxxxxxxxx>
Cc: Corentin Labbe <clabbe@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
kernel/dma/debug.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 099002d84f466af0a8e421d035ac8eb119e08bd8..4ad74f5987ea9e95f9bb5e2d1592254e367d24fb 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();
}
}

--
2.24.0.rc0.303.g954a862665-goog