From: Nicolin Chen <nicolinc@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: <will@kernel.org>, <jgg@nvidia.com>, <joro@8bytes.org>,
<jean-philippe@linaro.org>, <apopple@nvidia.com>,
<linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>, <iommu@lists.linux.dev>
Subject: Re: [PATCH 1/3] iommu/io-pgtable-arm: Add nents_per_pgtable in struct io_pgtable_cfg
Date: Tue, 22 Aug 2023 09:42:24 -0700 [thread overview]
Message-ID: <ZOTlcFs2NG6nJEPN@Asurada-Nvidia> (raw)
In-Reply-To: <f468b461-b203-5179-eb6d-9432b9911329@arm.com>
On Tue, Aug 22, 2023 at 10:19:21AM +0100, Robin Murphy wrote:
> > out_free_data:
> > @@ -1071,6 +1073,7 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
> > ARM_MALI_LPAE_TTBR_ADRMODE_TABLE;
> > if (cfg->coherent_walk)
> > cfg->arm_mali_lpae_cfg.transtab |= ARM_MALI_LPAE_TTBR_SHARE_OUTER;
> > + cfg->nents_per_pgtable = 1 << data->bits_per_level;
>
> The result of this highly complex and expensive calculation is clearly
> redundant with the existing bits_per_level field, so why do we need to
> waste space storing when the driver could simply use bits_per_level?
bits_per_level is in the private struct arm_lpae_io_pgtable, while
drivers can only access struct io_pgtable_cfg. Are you suggesting
to move bits_per_level out of the private struct arm_lpae_io_pgtable
to the public struct io_pgtable_cfg?
Or am I missing another bits_per_level?
Thanks
Nicolin
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next prev parent reply other threads:[~2023-08-22 16:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-22 8:45 [PATCH 0/3] iommu/arm-smmu-v3: Reduce latency in __arm_smmu_tlb_inv_range() Nicolin Chen
2023-08-22 8:45 ` [PATCH 1/3] iommu/io-pgtable-arm: Add nents_per_pgtable in struct io_pgtable_cfg Nicolin Chen
2023-08-22 9:19 ` Robin Murphy
2023-08-22 16:42 ` Nicolin Chen [this message]
2023-08-29 15:37 ` Robin Murphy
2023-08-29 20:15 ` Nicolin Chen
2023-08-29 21:25 ` Robin Murphy
2023-08-29 22:15 ` Nicolin Chen
2023-08-30 21:49 ` Will Deacon
2023-08-31 17:39 ` Nicolin Chen
2023-09-01 0:08 ` Nicolin Chen
2023-09-01 18:02 ` Robin Murphy
2023-09-01 18:23 ` Nicolin Chen
2024-01-20 19:59 ` Nicolin Chen
2024-01-22 13:01 ` Jason Gunthorpe
2024-01-22 17:24 ` Nicolin Chen
2024-01-22 17:57 ` Jason Gunthorpe
2024-01-24 0:11 ` Nicolin Chen
2024-01-25 13:55 ` Jason Gunthorpe
2024-01-25 17:23 ` Nicolin Chen
2024-01-25 17:47 ` Jason Gunthorpe
2024-01-25 19:55 ` Nicolin Chen
[not found] ` <098d64da-ecf5-4a23-bff9-a04840726ef0@huawei.com>
2024-01-25 5:09 ` Nicolin Chen
2023-08-22 8:45 ` [PATCH 2/3] iommu/arm-smmu-v3: Add an arm_smmu_tlb_inv_domain helper Nicolin Chen
2023-08-22 9:40 ` Robin Murphy
2023-08-22 17:03 ` Nicolin Chen
2023-08-29 21:54 ` Robin Murphy
2023-08-29 23:03 ` Nicolin Chen
2023-08-22 8:45 ` [PATCH 3/3] iommu/arm-smmu-v3: Add a max_tlbi_ops for __arm_smmu_tlb_inv_range() Nicolin Chen
2023-08-22 9:30 ` Robin Murphy
2023-08-22 16:32 ` Nicolin Chen
2023-08-22 23:04 ` Nicolin Chen
2023-08-29 22:40 ` Robin Murphy
2023-08-29 23:14 ` Nicolin Chen
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