From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "axboe@kernel.dk" <axboe@kernel.dk>,
"linux-renesas-soc@vger.kernel.org"
<linux-renesas-soc@vger.kernel.org>,
"ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"wsa+renesas@sang-engineering.com"
<wsa+renesas@sang-engineering.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>
Subject: RE: [RFC PATCH v6 5/5] mmc: queue: Use bigger segments if IOMMU can merge the segments
Date: Mon, 17 Jun 2019 06:46:33 +0000 [thread overview]
Message-ID: <OSBPR01MB3590FA5DB10D9EF34F551335D8EB0@OSBPR01MB3590.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <20190614072459.GD8420@lst.de>
Hi Christoph,
> From: Christoph Hellwig, Sent: Friday, June 14, 2019 4:25 PM
>
> On Thu, Jun 13, 2019 at 07:20:15PM +0900, Yoshihiro Shimoda wrote:
> > +static unsigned int mmc_get_max_segments(struct mmc_host *host)
> > +{
> > + return host->can_merge ? BLK_MAX_SEGMENTS : host->max_segs;
> > +}
>
> Note that BLK_MAX_SEGMENTS is really a little misnamed, it just
> is a BLK_DEFAULT_SEGMENTS. I think you are better of picking your
> own value here (even if 128 ends up ok) than reusing this somewhat
> confusing constant.
Thank you for your comments. I got it. I'll fix this.
> > + /*
> > + * Since blk_mq_alloc_tag_set() calls .init_request() of mmc_mq_ops,
> > + * the host->can_merge should be set before to get max_segs from
> > + * mmc_get_max_segments().
> > + */
> > + if (host->max_segs < BLK_MAX_SEGMENTS &&
> > + device_iommu_mapped(mmc_dev(host)))
> > + host->can_merge = 1;
> > + else
> > + host->can_merge = 0;
> > +
>
> can_merge seems a little too generic a name to me. Maybe can_iommu_merge?
I'll fix the name. Also, only the device_iommu_mapped() condition wiil cause
a problem on iommu=pt [1]. So, I'll add another condition here.
[1]
https://marc.info/?l=linux-mmc&m=156050608709643&w=2
Best regards,
Yoshihiro Shimoda
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next prev parent reply other threads:[~2019-06-17 6:46 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 10:20 [RFC PATCH v6 0/5] treewide: improve R-Car SDHI performance Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 1/5] iommu: add an exported function to get minimum page size for a domain Yoshihiro Shimoda
2019-06-13 19:37 ` Wolfram Sang
2019-06-14 7:16 ` Christoph Hellwig
2019-06-17 5:08 ` Yoshihiro Shimoda
2019-06-14 9:41 ` Robin Murphy
2019-06-17 5:23 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 2/5] block: sort headers on blk-setting.c Yoshihiro Shimoda
2019-06-13 19:40 ` Wolfram Sang
2019-06-13 10:20 ` [RFC PATCH v6 3/5] block: add a helper function to merge the segments by an IOMMU Yoshihiro Shimoda
2019-06-14 7:22 ` Christoph Hellwig
2019-06-14 9:54 ` Robin Murphy
2019-06-17 6:29 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 4/5] mmc: tmio: Use dma_max_mapping_size() instead of a workaround Yoshihiro Shimoda
2019-06-13 19:45 ` Wolfram Sang
2019-06-17 4:25 ` Yoshihiro Shimoda
2019-06-13 20:35 ` Geert Uytterhoeven
2019-06-14 7:18 ` Christoph Hellwig
2019-06-14 7:27 ` Geert Uytterhoeven
2019-06-17 4:54 ` Yoshihiro Shimoda
2019-06-17 6:23 ` Geert Uytterhoeven
2019-06-17 6:54 ` Yoshihiro Shimoda
2019-06-13 10:20 ` [RFC PATCH v6 5/5] mmc: queue: Use bigger segments if IOMMU can merge the segments Yoshihiro Shimoda
2019-06-13 19:58 ` Wolfram Sang
2019-06-17 6:38 ` Yoshihiro Shimoda
2019-06-14 7:24 ` Christoph Hellwig
2019-06-14 10:42 ` Wolfram Sang
2019-06-17 6:46 ` Yoshihiro Shimoda [this message]
2019-06-17 6:53 ` Christoph Hellwig
2019-06-17 7:02 ` Yoshihiro Shimoda
2019-06-13 19:36 ` [RFC PATCH v6 0/5] treewide: improve R-Car SDHI performance Wolfram Sang
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