From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>
Cc: patches@lists.linux.dev, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH] iommupt: Optimize the gather processing for DMA-FQ mode
Date: Tue, 3 Mar 2026 11:55:33 +0800 [thread overview]
Message-ID: <d1a49e84-9829-41ef-88df-c7f7a30aa2ae@linux.intel.com> (raw)
In-Reply-To: <0-v1-37d146e56632+ce4-iommupt_no_gaps_fq_jgg@nvidia.com>
On 2/27/26 23:27, Jason Gunthorpe wrote:
> In PT_FEAT_FLUSH_RANGE mode the gather was accumulated but never flushed
> and then the accumulated range was discarded by the dma-iommu code in
> DMA-FQ mode. This is basically optimal.
>
> However for PT_FEAT_FLUSH_RANGE_NO_GAPS the page table would push flushes
> that are redundant with the flush all generated by the DMA-FQ mode.
>
> Disable all range accumulation in the gather, and iommu_pt triggered
> flushing when in iommu_iotlb_gather_queued() indicates it is in DMA-FQ
> mode.
>
> Reported-by: Robin Murphy<robin.murphy@arm.com>
> Closes:https://lore.kernel.org/r/794b6121-b66b-4819-b291-9761ed21cd83@arm.com
> Signed-off-by: Jason Gunthorpe<jgg@nvidia.com>
> ---
> drivers/iommu/generic_pt/iommu_pt.h | 27 +++++++++++++++++++--------
> 1 file changed, 19 insertions(+), 8 deletions(-)
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
next prev parent reply other threads:[~2026-03-03 3:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-27 15:27 [PATCH] iommupt: Optimize the gather processing for DMA-FQ mode Jason Gunthorpe
2026-02-27 21:02 ` Samiullah Khawaja
2026-03-03 3:55 ` Baolu Lu [this message]
2026-03-17 12:15 ` Joerg Roedel
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