[PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[chenxiang]

From: Xiang Chen <chenxiang66@hisilicon.com>

It is not necessary to put free_iova_mem() inside of spinlock/unlock
iova_rbtree_lock which only leads to more completion for the spinlock.
It has a small promote on the performance after the change. And also
rename private_free_iova() as remove_iova() because the function will not
free iova after that change.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
---
 drivers/iommu/iova.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index b7ecd5b..b6cf5f1 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -412,12 +412,11 @@ private_find_iova(struct iova_domain *iovad, unsigned long pfn)
 	return NULL;
 }
 
-static void private_free_iova(struct iova_domain *iovad, struct iova *iova)
+static void remove_iova(struct iova_domain *iovad, struct iova *iova)
 {
 	assert_spin_locked(&iovad->iova_rbtree_lock);
 	__cached_rbnode_delete_update(iovad, iova);
 	rb_erase(&iova->node, &iovad->rbroot);
-	free_iova_mem(iova);
 }
 
 /**
@@ -452,8 +451,9 @@ __free_iova(struct iova_domain *iovad, struct iova *iova)
 	unsigned long flags;
 
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
-	private_free_iova(iovad, iova);
+	remove_iova(iovad, iova);
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+	free_iova_mem(iova);
 }
 EXPORT_SYMBOL_GPL(__free_iova);
 
@@ -472,10 +472,13 @@ free_iova(struct iova_domain *iovad, unsigned long pfn)
 
 	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
 	iova = private_find_iova(iovad, pfn);
-	if (iova)
-		private_free_iova(iovad, iova);
+	if (!iova) {
+		spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
+		return;
+	}
+	remove_iova(iovad, iova);
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
-
+	free_iova_mem(iova);
 }
 EXPORT_SYMBOL_GPL(free_iova);
 
@@ -825,7 +828,8 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
 		if (WARN_ON(!iova))
 			continue;
 
-		private_free_iova(iovad, iova);
+		remove_iova(iovad, iova);
+		free_iova_mem(iova);
 	}
 
 	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
-- 
2.8.1

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Re: [PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[John Garry]

On 19/04/2021 08:13, chenxiang wrote:
> From: Xiang Chen<chenxiang66@hisilicon.com>
> 
> It is not necessary to put free_iova_mem() inside of spinlock/unlock
> iova_rbtree_lock which only leads to more completion for the spinlock.
> It has a small promote on the performance after the change. And also
> rename private_free_iova() as remove_iova() because the function will not
> free iova after that change.
> 
> Signed-off-by: Xiang Chen<chenxiang66@hisilicon.com>

I think that you will need to resend after v5.13-rc1 comes out, however:

Reviewed-by: John Garry <john.garry@huawei.com>

> ---
>   drivers/iommu/



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Re: [PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[Joerg Roedel]

On Mon, Apr 19, 2021 at 03:13:35PM +0800, chenxiang wrote:
> From: Xiang Chen <chenxiang66@hisilicon.com>
> 
> It is not necessary to put free_iova_mem() inside of spinlock/unlock
> iova_rbtree_lock which only leads to more completion for the spinlock.
> It has a small promote on the performance after the change. And also
> rename private_free_iova() as remove_iova() because the function will not
> free iova after that change.
> 
> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
> ---
>  drivers/iommu/iova.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)

Looks good to me, but I'll wait for Robins opinion before applying.

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Re: [PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[chenxiang (M)]

Hi Joerg,

在 2021/5/18 17:08, Joerg Roedel 写道:
> On Mon, Apr 19, 2021 at 03:13:35PM +0800, chenxiang wrote:
>> From: Xiang Chen <chenxiang66@hisilicon.com>
>>
>> It is not necessary to put free_iova_mem() inside of spinlock/unlock
>> iova_rbtree_lock which only leads to more completion for the spinlock.
>> It has a small promote on the performance after the change. And also
>> rename private_free_iova() as remove_iova() because the function will not
>> free iova after that change.
>>
>> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
>> ---
>>   drivers/iommu/iova.c | 18 +++++++++++-------
>>   1 file changed, 11 insertions(+), 7 deletions(-)
> Looks good to me, but I'll wait for Robins opinion before applying.

I have re-sent v3, and Robin has given his acked-by:
https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg50950.html

>
>
> .
>


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Re: [PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[Robin Murphy]

On 2021-05-18 10:08, Joerg Roedel wrote:
> On Mon, Apr 19, 2021 at 03:13:35PM +0800, chenxiang wrote:
>> From: Xiang Chen <chenxiang66@hisilicon.com>
>>
>> It is not necessary to put free_iova_mem() inside of spinlock/unlock
>> iova_rbtree_lock which only leads to more completion for the spinlock.
>> It has a small promote on the performance after the change. And also
>> rename private_free_iova() as remove_iova() because the function will not
>> free iova after that change.
>>
>> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
>> ---
>>   drivers/iommu/iova.c | 18 +++++++++++-------
>>   1 file changed, 11 insertions(+), 7 deletions(-)
> 
> Looks good to me, but I'll wait for Robins opinion before applying.

Go ahead - I acked the resend[1] :)

Thanks,
Robin.

[1] 
https://lore.kernel.org/linux-iommu/9edc6849-f9ff-f6fc-30a0-8bb2e8d3bd0d@arm.com/
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Re: [PATCH v3] iommu/iova: put free_iova_mem() outside of spinlock iova_rbtree_lock

[Joerg Roedel]

On Tue, May 18, 2021 at 11:08:47AM +0200, Joerg Roedel wrote:
> Looks good to me, but I'll wait for Robins opinion before applying.

Nevermind, just found the new version which Robin already acked.
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