From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
Sagi Grimberg <sagi@grimberg.me>,
Chaitanya Kulkarni <kch@nvidia.com>,
Kanchan Joshi <joshi.k@samsung.com>,
Leon Romanovsky <leon@kernel.org>,
Nitesh Shetty <nj.shetty@samsung.com>,
Logan Gunthorpe <logang@deltatee.com>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCH 3/8] nvme-pci: refactor nvme_pci_use_sgls
Date: Tue, 24 Jun 2025 14:46:25 +0200 [thread overview]
Message-ID: <20250624124625.GA19239@lst.de> (raw)
In-Reply-To: <aFlyYjALviyhQ-IE@kbusch-mbp>
On Mon, Jun 23, 2025 at 09:27:30AM -0600, Keith Busch wrote:
> > - if (nvme_pci_use_sgls(dev, req, iod->sgt.nents))
> > + if (use_sgl == SGL_FORCED ||
> > + (use_sgl == SGL_SUPPORTED &&
> > + (!sgl_threshold || nvme_pci_avg_seg_size(req) >= sgl_threshold)))
> > ret = nvme_pci_setup_sgls(nvmeq, req, &cmnd->rw);
>
> We historically interpreted sgl_threshold set to 0 to mean disable SGL
> usage, maybe because the controller is broken or something. It might be
> okay to have 0 mean to not consider segment sizes, but I just wanted to
> point out this is a different interpretation of the user parameter.
This is still a leftover from the threshold mess in the first version.
I'll fix it for the next one.
next prev parent reply other threads:[~2025-06-24 12:46 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-23 14:12 new DMA API conversion for nvme-pci v2 Christoph Hellwig
2025-06-23 14:12 ` [PATCH 1/8] block: don't merge different kinds of P2P transfers in a single bio Christoph Hellwig
2025-06-23 15:43 ` Keith Busch
2025-06-23 14:12 ` [PATCH 2/8] block: add scatterlist-less DMA mapping helpers Christoph Hellwig
2025-06-23 15:43 ` Keith Busch
2025-06-23 14:12 ` [PATCH 3/8] nvme-pci: refactor nvme_pci_use_sgls Christoph Hellwig
2025-06-23 15:27 ` Keith Busch
2025-06-24 12:46 ` Christoph Hellwig [this message]
2025-06-25 4:28 ` Chaitanya Kulkarni
2025-06-25 6:07 ` Christoph Hellwig
2025-06-23 14:12 ` [PATCH 4/8] nvme-pci: merge the simple PRP and SGL setup into a common helper Christoph Hellwig
2025-06-23 15:43 ` Keith Busch
2025-06-23 14:12 ` [PATCH 5/8] nvme-pci: remove superfluous arguments Christoph Hellwig
2025-06-23 14:12 ` [PATCH 6/8] nvme-pci: convert the data mapping to blk_rq_dma_map Christoph Hellwig
2025-06-23 15:44 ` Keith Busch
2025-06-23 14:12 ` [PATCH 7/8] nvme-pci: replace NVME_MAX_KB_SZ with NVME_MAX_BYTE Christoph Hellwig
2025-06-23 15:44 ` Keith Busch
2025-06-23 14:12 ` [PATCH 8/8] nvme-pci: rework the build time assert for NVME_MAX_NR_DESCRIPTORS Christoph Hellwig
2025-06-23 15:44 ` Keith Busch
2025-06-23 21:45 ` new DMA API conversion for nvme-pci v2 Chaitanya Kulkarni
2025-06-25 4:32 ` Chaitanya Kulkarni
-- strict thread matches above, loose matches on Subject: below --
2025-06-25 11:34 new DMA API conversion for nvme-pci v3 Christoph Hellwig
2025-06-25 11:35 ` [PATCH 3/8] nvme-pci: refactor nvme_pci_use_sgls Christoph Hellwig
2025-06-25 16:03 ` Keith Busch
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