From: John Garry <john.garry@huawei.com> To: Cong Wang <xiyou.wangcong@gmail.com>, <iommu@lists.linux-foundation.org> Cc: <linux-kernel@vger.kernel.org> Subject: Re: [Patch v2 3/3] iommu: avoid taking iova_rbtree_lock twice Date: Fri, 29 Nov 2019 13:34:03 +0000 [thread overview] Message-ID: <dea0de02-cedc-7817-5b04-3888e0e86812@huawei.com> (raw) In-Reply-To: <20191129004855.18506-4-xiyou.wangcong@gmail.com> On 29/11/2019 00:48, Cong Wang wrote: > Both find_iova() and __free_iova() take iova_rbtree_lock, > there is no reason to take and release it twice inside > free_iova(). > > Fold them into the critical section by calling the unlock > versions instead. Since generally the iova would be non-NULL, this seems a reasonable change (which could be mentioned in the commit log) John > > Cc: Joerg Roedel <joro@8bytes.org> > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> > --- > drivers/iommu/iova.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 184d4c0e20b5..f46f8f794678 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -390,10 +390,14 @@ EXPORT_SYMBOL_GPL(__free_iova); > void > free_iova(struct iova_domain *iovad, unsigned long pfn) > { > - struct iova *iova = find_iova(iovad, pfn); > + unsigned long flags; > + struct iova *iova; > > + spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); > + iova = private_find_iova(iovad, pfn); > if (iova) > - __free_iova(iovad, iova); > + private_free_iova(iovad, iova); > + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); > > } > EXPORT_SYMBOL_GPL(free_iova); >
WARNING: multiple messages have this Message-ID (diff)
From: John Garry <john.garry@huawei.com> To: Cong Wang <xiyou.wangcong@gmail.com>, <iommu@lists.linux-foundation.org> Cc: linux-kernel@vger.kernel.org Subject: Re: [Patch v2 3/3] iommu: avoid taking iova_rbtree_lock twice Date: Fri, 29 Nov 2019 13:34:03 +0000 [thread overview] Message-ID: <dea0de02-cedc-7817-5b04-3888e0e86812@huawei.com> (raw) In-Reply-To: <20191129004855.18506-4-xiyou.wangcong@gmail.com> On 29/11/2019 00:48, Cong Wang wrote: > Both find_iova() and __free_iova() take iova_rbtree_lock, > there is no reason to take and release it twice inside > free_iova(). > > Fold them into the critical section by calling the unlock > versions instead. Since generally the iova would be non-NULL, this seems a reasonable change (which could be mentioned in the commit log) John > > Cc: Joerg Roedel <joro@8bytes.org> > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> > --- > drivers/iommu/iova.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 184d4c0e20b5..f46f8f794678 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -390,10 +390,14 @@ EXPORT_SYMBOL_GPL(__free_iova); > void > free_iova(struct iova_domain *iovad, unsigned long pfn) > { > - struct iova *iova = find_iova(iovad, pfn); > + unsigned long flags; > + struct iova *iova; > > + spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); > + iova = private_find_iova(iovad, pfn); > if (iova) > - __free_iova(iovad, iova); > + private_free_iova(iovad, iova); > + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); > > } > EXPORT_SYMBOL_GPL(free_iova); > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-11-29 13:34 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-29 0:48 [Patch v2 0/3] iommu: reduce spinlock contention on fast path Cong Wang 2019-11-29 0:48 ` Cong Wang 2019-11-29 0:48 ` [Patch v2 1/3] iommu: match the original algorithm Cong Wang 2019-11-29 0:48 ` Cong Wang 2019-11-29 14:43 ` John Garry 2019-11-29 14:43 ` John Garry 2019-11-30 5:58 ` Cong Wang 2019-11-30 5:58 ` Cong Wang 2019-12-02 10:55 ` John Garry 2019-12-02 10:55 ` John Garry 2019-12-03 19:26 ` Cong Wang 2019-12-03 19:26 ` Cong Wang 2019-12-02 16:58 ` Christoph Hellwig 2019-12-02 16:58 ` Christoph Hellwig 2019-12-03 19:24 ` Cong Wang 2019-12-03 19:24 ` Cong Wang 2019-11-29 0:48 ` [Patch v2 2/3] iommu: optimize iova_magazine_free_pfns() Cong Wang 2019-11-29 0:48 ` Cong Wang 2019-11-29 13:24 ` John Garry 2019-11-29 13:24 ` John Garry 2019-11-30 6:02 ` Cong Wang 2019-11-30 6:02 ` Cong Wang 2019-12-02 10:02 ` John Garry 2019-12-02 10:02 ` John Garry 2019-12-03 19:40 ` Cong Wang 2019-12-03 19:40 ` Cong Wang 2019-12-02 16:59 ` Christoph Hellwig 2019-12-02 16:59 ` Christoph Hellwig 2019-12-03 19:28 ` Cong Wang 2019-12-03 19:28 ` Cong Wang 2019-11-29 0:48 ` [Patch v2 3/3] iommu: avoid taking iova_rbtree_lock twice Cong Wang 2019-11-29 0:48 ` Cong Wang 2019-11-29 13:34 ` John Garry [this message] 2019-11-29 13:34 ` John Garry 2019-11-30 6:03 ` Cong Wang 2019-11-30 6:03 ` Cong Wang 2019-12-17 9:43 ` [Patch v2 0/3] iommu: reduce spinlock contention on fast path Joerg Roedel 2019-12-17 9:43 ` Joerg Roedel 2019-12-18 4:32 ` Cong Wang 2019-12-18 4:32 ` Cong Wang
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