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Date:   Mon, 25 Sep 2023 10:12:14 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Huang Jiaqing <jiaqing.huang@intel.com>
Cc:     kvm@vger.kernel.org, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org, will@kernel.org,
        robin.murphy@arm.com, kevin.tian@intel.com,
        baolu.lu@linux.intel.com, jacob.jun.pan@linux.intel.com,
        yi.l.liu@intel.com, yi.y.sun@intel.com
Subject: Re: [PATCH] iommu/vt-d: Introduce a rb_tree for looking up device
Message-ID: <ZRFA3uj1-QjlXpGx@8bytes.org>
References: <20230821071659.123981-1-jiaqing.huang@intel.com>
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On Mon, Aug 21, 2023 at 12:16:59AM -0700, Huang Jiaqing wrote:
> The existing IO page fault handler locates the PCI device by calling
> pci_get_domain_bus_and_slot(), which searches the list of all PCI
> devices until the desired PCI device is found. This is inefficient
> because the algorithm efficiency of searching a list is O(n). In the
> critical path of handling an IO page fault, this can cause a significant
> performance bottleneck.

Can you elaborate a little more on the 'significant performance
bottleneck' part? Where do you see this as a problem?

Regards,

	Joerg