[PATCH v4 21/26] iommu/arm-smmu-v3: Ratelimit event dump
From: Jean-Philippe Brucker <hidden>
Date: 2020-02-24 18:25:27
Also in:
linux-devicetree, linux-iommu, linux-mm, linux-pci
Subsystem:
iommu subsystem, the rest · Maintainers:
Joerg Roedel, Will Deacon, Linus Torvalds
When a device or driver misbehaves, it is possible to receive events much faster than we can print them out. Ratelimit the printing of events. Signed-off-by: Jean-Philippe Brucker <redacted> --- During the SVA tests when the device driver didn't properly stop DMA before unbinding, the event queue thread would almost lock-up the server with a flood of event 0xa. This patch helped recover from the error. --- drivers/iommu/arm-smmu-v3.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 28f8583cd47b..6a5987cce03f 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c@@ -2243,17 +2243,20 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) struct arm_smmu_device *smmu = dev; struct arm_smmu_queue *q = &smmu->evtq.q; struct arm_smmu_ll_queue *llq = &q->llq; + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); u64 evt[EVTQ_ENT_DWORDS]; do { while (!queue_remove_raw(q, evt)) { u8 id = FIELD_GET(EVTQ_0_ID, evt[0]); - dev_info(smmu->dev, "event 0x%02x received:\n", id); - for (i = 0; i < ARRAY_SIZE(evt); ++i) - dev_info(smmu->dev, "\t0x%016llx\n", - (unsigned long long)evt[i]); - + if (__ratelimit(&rs)) { + dev_info(smmu->dev, "event 0x%02x received:\n", id); + for (i = 0; i < ARRAY_SIZE(evt); ++i) + dev_info(smmu->dev, "\t0x%016llx\n", + (unsigned long long)evt[i]); + } } /*
--
2.25.0
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