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Message-ID: <20180213132959.kkavgzt37hm7n2tt@8bytes.org>
Date: Tue, 13 Feb 2018 14:29:59 +0100
From: Joerg Roedel <joro@...tes.org>
To: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Cc: iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
jroedel@...e.de
Subject: Re: [PATCH v3] iommu/amd: Add support for fast IOTLB flushing
Hi Suravee,
thanks for working on this.
On Wed, Jan 31, 2018 at 12:01:14AM -0500, Suravee Suthikulpanit wrote:
> +static void amd_iommu_iotlb_range_add(struct iommu_domain *domain,
> + unsigned long iova, size_t size)
> +{
> + struct amd_iommu_flush_entries *entry, *p;
> + unsigned long flags;
> + bool found = false;
> +
> + spin_lock_irqsave(&amd_iommu_flush_list_lock, flags);
I am not happy with introducing or using global locks when they are not
necessary. Can this be a per-domain lock?
Besides, did you check it makes sense to actually keep track of the
ranges here? My approach would be to just make iotlb_range_add() an noop
and do a full domain flush in iotlb_sync(). But maybe you did
measurements you can share here to show there is a benefit.
Joerg
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