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* [PATCH 1/1] iommu/arm-smmu-v3: Decrease the queue size of evtq and priq
@ 2021-05-31 12:35 Zhen Lei
  2021-06-08 11:42 ` Will Deacon
  0 siblings, 1 reply; 2+ messages in thread
From: Zhen Lei @ 2021-05-31 12:35 UTC (permalink / raw)
  To: Will Deacon, Robin Murphy, Joerg Roedel, linux-arm-kernel, iommu,
	linux-kernel
  Cc: Zhen Lei

Commit d25f6ead162e ("iommu/arm-smmu-v3: Increase maximum size of queues")
expands the cmdq queue size to improve the success rate of concurrent
command queue space allocation by multiple cores. However, this extension
does not apply to evtq and priq, because for both of them, the SMMU driver
is the consumer. Instead, memory resources are wasted. Therefore, the
queue size of evtq and priq is restored to the original setting, one page.

Fixes: d25f6ead162e ("iommu/arm-smmu-v3: Increase maximum size of queues")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 46e8c49214a872e..8e5094fa2863df5 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -184,6 +184,7 @@
 #else
 #define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + MAX_ORDER - 1)
 #endif
+#define Q_MIN_SZ_SHIFT			(PAGE_SHIFT)
 
 /*
  * Stream table.
@@ -366,14 +367,14 @@
 /* Event queue */
 #define EVTQ_ENT_SZ_SHIFT		5
 #define EVTQ_ENT_DWORDS			((1 << EVTQ_ENT_SZ_SHIFT) >> 3)
-#define EVTQ_MAX_SZ_SHIFT		(Q_MAX_SZ_SHIFT - EVTQ_ENT_SZ_SHIFT)
+#define EVTQ_MAX_SZ_SHIFT		(Q_MIN_SZ_SHIFT - EVTQ_ENT_SZ_SHIFT)
 
 #define EVTQ_0_ID			GENMASK_ULL(7, 0)
 
 /* PRI queue */
 #define PRIQ_ENT_SZ_SHIFT		4
 #define PRIQ_ENT_DWORDS			((1 << PRIQ_ENT_SZ_SHIFT) >> 3)
-#define PRIQ_MAX_SZ_SHIFT		(Q_MAX_SZ_SHIFT - PRIQ_ENT_SZ_SHIFT)
+#define PRIQ_MAX_SZ_SHIFT		(Q_MIN_SZ_SHIFT - PRIQ_ENT_SZ_SHIFT)
 
 #define PRIQ_0_SID			GENMASK_ULL(31, 0)
 #define PRIQ_0_SSID			GENMASK_ULL(51, 32)
-- 
2.26.0.106.g9fadedd



^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH 1/1] iommu/arm-smmu-v3: Decrease the queue size of evtq and priq
  2021-05-31 12:35 [PATCH 1/1] iommu/arm-smmu-v3: Decrease the queue size of evtq and priq Zhen Lei
@ 2021-06-08 11:42 ` Will Deacon
  0 siblings, 0 replies; 2+ messages in thread
From: Will Deacon @ 2021-06-08 11:42 UTC (permalink / raw)
  To: linux-kernel, iommu, Robin Murphy, Zhen Lei, linux-arm-kernel,
	Joerg Roedel
  Cc: catalin.marinas, kernel-team, Will Deacon

On Mon, 31 May 2021 20:35:53 +0800, Zhen Lei wrote:
> Commit d25f6ead162e ("iommu/arm-smmu-v3: Increase maximum size of queues")
> expands the cmdq queue size to improve the success rate of concurrent
> command queue space allocation by multiple cores. However, this extension
> does not apply to evtq and priq, because for both of them, the SMMU driver
> is the consumer. Instead, memory resources are wasted. Therefore, the
> queue size of evtq and priq is restored to the original setting, one page.

Applied to will (for-joerg/arm-smmu/updates), thanks!

[1/1] iommu/arm-smmu-v3: Decrease the queue size of evtq and priq
      https://git.kernel.org/will/c/f115f3c0d5d8

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

^ permalink raw reply	[flat|nested] 2+ messages in thread

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