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From: John Garry <john.garry@huawei.com>
To: Robin Murphy <robin.murphy@arm.com>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"will@kernel.org" <will@kernel.org>,
	"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
	"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
	"hch@lst.de" <hch@lst.de>,
	"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>
Cc: "iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	Linuxarm <linuxarm@huawei.com>
Subject: Re: [PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator
Date: Mon, 22 Mar 2021 15:01:00 +0000	[thread overview]
Message-ID: <08c0f4b9-8713-fa97-3986-3cfb0d6b820b@huawei.com> (raw)
In-Reply-To: <afc2fc05-a799-cb14-debd-d36afed8f456@arm.com>

On 19/03/2021 19:20, Robin Murphy wrote:

Hi Robin,

>> So then we have the issue of how to dynamically increase this rcache
>> threshold. The problem is that we may have many devices associated with
>> the same domain. So, in theory, we can't assume that when we increase
>> the threshold that some other device will try to fast free an IOVA which
>> was allocated prior to the increase and was not rounded up.
>>
>> I'm very open to better (or less bad) suggestions on how to do this ...
> ...but yes, regardless of exactly where it happens, rounding up or not
> is the problem for rcaches in general. I've said several times that my
> preferred approach is to not change it that dynamically at all, but
> instead treat it more like we treat the default domain type.
> 

Can you remind me of that idea? I don't remember you mentioning using 
default domain handling as a reference in any context.

Thanks,
John

WARNING: multiple messages have this Message-ID (diff)
From: John Garry <john.garry@huawei.com>
To: Robin Murphy <robin.murphy@arm.com>,
	"joro@8bytes.org" <joro@8bytes.org>,
	 "will@kernel.org" <will@kernel.org>,
	"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
	"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
	"hch@lst.de" <hch@lst.de>,
	"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>
Cc: "iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	Linuxarm <linuxarm@huawei.com>
Subject: Re: [PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator
Date: Mon, 22 Mar 2021 15:01:00 +0000	[thread overview]
Message-ID: <08c0f4b9-8713-fa97-3986-3cfb0d6b820b@huawei.com> (raw)
In-Reply-To: <afc2fc05-a799-cb14-debd-d36afed8f456@arm.com>

On 19/03/2021 19:20, Robin Murphy wrote:

Hi Robin,

>> So then we have the issue of how to dynamically increase this rcache
>> threshold. The problem is that we may have many devices associated with
>> the same domain. So, in theory, we can't assume that when we increase
>> the threshold that some other device will try to fast free an IOVA which
>> was allocated prior to the increase and was not rounded up.
>>
>> I'm very open to better (or less bad) suggestions on how to do this ...
> ...but yes, regardless of exactly where it happens, rounding up or not
> is the problem for rcaches in general. I've said several times that my
> preferred approach is to not change it that dynamically at all, but
> instead treat it more like we treat the default domain type.
> 

Can you remind me of that idea? I don't remember you mentioning using 
default domain handling as a reference in any context.

Thanks,
John
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2021-03-22 15:04 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 13:25 [PATCH 0/6] dma mapping/iommu: Allow IOMMU IOVA rcache range to be configured John Garry
2021-03-19 13:25 ` John Garry
2021-03-19 13:25 ` [PATCH 1/6] iommu: Move IOVA power-of-2 roundup into allocator John Garry
2021-03-19 13:25   ` John Garry
2021-03-19 16:13   ` Robin Murphy
2021-03-19 16:13     ` Robin Murphy
2021-03-19 16:58     ` John Garry
2021-03-19 16:58       ` John Garry
2021-03-19 19:20       ` Robin Murphy
2021-03-19 19:20         ` Robin Murphy
2021-03-22 15:01         ` John Garry [this message]
2021-03-22 15:01           ` John Garry
2021-03-31  9:58           ` Robin Murphy
2021-03-31  9:58             ` Robin Murphy
2021-04-06 16:54             ` John Garry
2021-04-06 16:54               ` John Garry
2021-04-14 17:44               ` John Garry
2021-04-14 17:44                 ` John Garry
2021-03-19 13:25 ` [PATCH 2/6] iova: Add a per-domain count of reserved nodes John Garry
2021-03-19 13:25   ` John Garry
2021-03-19 13:25 ` [PATCH 3/6] iova: Allow rcache range upper limit to be configurable John Garry
2021-03-19 13:25   ` John Garry
2021-03-19 16:25   ` Robin Murphy
2021-03-19 16:25     ` Robin Murphy
2021-03-19 17:26     ` John Garry
2021-03-19 17:26       ` John Garry
2021-03-31 10:53       ` Robin Murphy
2021-03-31 10:53         ` Robin Murphy
2021-03-19 13:25 ` [PATCH 4/6] iommu: Add iommu_dma_set_opt_size() John Garry
2021-03-19 13:25   ` John Garry
2021-03-19 13:25 ` [PATCH 5/6] dma-mapping/iommu: Add dma_set_max_opt_size() John Garry
2021-03-19 13:25   ` John Garry
2021-03-19 17:00   ` Robin Murphy
2021-03-19 17:00     ` Robin Murphy
2021-03-19 18:02     ` John Garry
2021-03-19 18:02       ` John Garry
2021-03-31  8:01     ` Salil Mehta
2021-03-31  8:01       ` Salil Mehta
2021-03-31  8:08     ` Salil Mehta
2021-03-31  8:08       ` Salil Mehta
2021-03-19 13:25 ` [PATCH 6/6] scsi: hisi_sas: Set max optimal DMA size for v3 hw John Garry
2021-03-19 13:25   ` John Garry
2021-03-19 13:40 ` [PATCH 0/6] dma mapping/iommu: Allow IOMMU IOVA rcache range to be configured Christoph Hellwig
2021-03-19 13:40   ` Christoph Hellwig
2021-03-19 15:42   ` John Garry
2021-03-19 15:42     ` John Garry

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