From: Bart Van Assche <bvanassche@acm.org>
To: John Garry <john.garry@huawei.com>,
damien.lemoal@opensource.wdc.com, joro@8bytes.org,
will@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com,
hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-ide@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-scsi@vger.kernel.org, liyihang6@hisilicon.com,
chenxiang66@hisilicon.com, thunder.leizhen@huawei.com
Subject: Re: [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits
Date: Wed, 8 Jun 2022 10:33:26 -0700 [thread overview]
Message-ID: <fe365aa8-00d5-153d-ceb2-f887a71a6927@acm.org> (raw)
In-Reply-To: <1654507822-168026-4-git-send-email-john.garry@huawei.com>
On 6/6/22 02:30, John Garry wrote:
> + if (dma_dev->dma_mask) {
> + shost->max_sectors = min_t(unsigned int, shost->max_sectors,
> + dma_opt_mapping_size(dma_dev) >> SECTOR_SHIFT);
> + }
Since IOVA_RANGE_CACHE_MAX_SIZE = 6 this limits max_sectors to 2**6 *
PAGE_SIZE or 256 KiB if the page size is 4 KiB. I think that's too
small. Some (SRP) storage arrays require much larger transfers to
achieve optimal performance.
Thanks,
Bart.
next prev parent reply other threads:[~2022-06-08 17:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-06 9:30 [PATCH v3 0/4] DMA mapping changes for SCSI core John Garry
2022-06-06 9:30 ` [PATCH v3 1/4] dma-mapping: Add dma_opt_mapping_size() John Garry
2022-06-08 17:27 ` Bart Van Assche
2022-06-06 9:30 ` [PATCH v3 2/4] dma-iommu: Add iommu_dma_opt_mapping_size() John Garry
2022-06-08 17:26 ` Bart Van Assche
2022-06-08 17:39 ` John Garry
2022-06-14 13:12 ` John Garry
2022-06-23 8:38 ` John Garry
2022-06-06 9:30 ` [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits John Garry
2022-06-08 17:33 ` Bart Van Assche [this message]
2022-06-08 17:50 ` John Garry
2022-06-08 21:07 ` Bart Van Assche
2022-06-09 8:00 ` John Garry
2022-06-09 17:18 ` Bart Van Assche
2022-06-09 17:54 ` John Garry
2022-06-09 20:34 ` Bart Van Assche
2022-06-10 15:37 ` John Garry
2022-06-23 8:36 ` John Garry
2022-06-06 9:30 ` [PATCH v3 4/4] libata-scsi: Cap ata_device->max_sectors according to shost->max_sectors John Garry
2022-06-07 22:43 ` [PATCH v3 0/4] DMA mapping changes for SCSI core Bart Van Assche
2022-06-08 10:14 ` John Garry
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