From: <Tudor.Ambarus@microchip.com>
To: <vkoul@kernel.org>
Cc: <Ludovic.Desroches@microchip.com>, <richard.genoud@gmail.com>,
<gregkh@linuxfoundation.org>, <jirislaby@kernel.org>,
<Nicolas.Ferre@microchip.com>, <alexandre.belloni@bootlin.com>,
<mripard@kernel.org>, <linux-arm-kernel@lists.infradead.org>,
<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-serial@vger.kernel.org>
Subject: Re: [PATCH v2 08/13] dmaengine: at_xdmac: Move the free desc to the tail of the desc list
Date: Mon, 13 Dec 2021 08:51:25 +0000 [thread overview]
Message-ID: <8523ca32-d36f-6e0b-0115-5e07553396f1@microchip.com> (raw)
In-Reply-To: <Ybb/PV5M1Gi59s7I@matsya>
Hi, Vinod,
On 12/13/21 10:07 AM, Vinod Koul wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> On 25-11-21, 11:00, Tudor Ambarus wrote:
>> So that we don't use the same desc over and over again.
>
> Please use full para in the changelog and not a continuation of the
> patch title!
Ok, will add a better commit description. Here and in other patches where
your comment applies.
>
> and why is wrong with using same desc over and over? Any benefits of not
> doing so?
Not wrong, but if we move the free desc to the tail of the list, then the
sequence of descriptors is more track-able in case of debug. You would
know which descriptor should come next and you could easier catch
concurrency over descriptors for example. I saw virt-dma uses
list_splice_tail_init() as well, I found it a good idea, so I thought to
follow the core driver.
Cheers,
ta
WARNING: multiple messages have this Message-ID (diff)
From: <Tudor.Ambarus@microchip.com>
To: <vkoul@kernel.org>
Cc: alexandre.belloni@bootlin.com, richard.genoud@gmail.com,
gregkh@linuxfoundation.org, mripard@kernel.org,
linux-kernel@vger.kernel.org, Ludovic.Desroches@microchip.com,
linux-serial@vger.kernel.org, dmaengine@vger.kernel.org,
jirislaby@kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 08/13] dmaengine: at_xdmac: Move the free desc to the tail of the desc list
Date: Mon, 13 Dec 2021 08:51:25 +0000 [thread overview]
Message-ID: <8523ca32-d36f-6e0b-0115-5e07553396f1@microchip.com> (raw)
In-Reply-To: <Ybb/PV5M1Gi59s7I@matsya>
Hi, Vinod,
On 12/13/21 10:07 AM, Vinod Koul wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> On 25-11-21, 11:00, Tudor Ambarus wrote:
>> So that we don't use the same desc over and over again.
>
> Please use full para in the changelog and not a continuation of the
> patch title!
Ok, will add a better commit description. Here and in other patches where
your comment applies.
>
> and why is wrong with using same desc over and over? Any benefits of not
> doing so?
Not wrong, but if we move the free desc to the tail of the list, then the
sequence of descriptors is more track-able in case of debug. You would
know which descriptor should come next and you could easier catch
concurrency over descriptors for example. I saw virt-dma uses
list_splice_tail_init() as well, I found it a good idea, so I thought to
follow the core driver.
Cheers,
ta
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next prev parent reply other threads:[~2021-12-13 8:51 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 9:00 [PATCH v2 00/13] dmaengine: at_xdmac: Various fixes Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 01/13] dmaengine: at_xdmac: Don't start transactions at tx_submit level Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 02/13] tty: serial: atmel: Check return code of dmaengine_submit() Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 03/13] tty: serial: atmel: Call dma_async_issue_pending() Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 04/13] dmaengine: at_xdmac: Start transfer for cyclic channels in issue_pending Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 05/13] dmaengine: at_xdmac: Print debug message after realeasing the lock Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 06/13] dmaengine: at_xdmac: Fix concurrency over chan's completed_cookie Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 07/13] dmaengine: at_xdmac: Fix race for the tx desc callback Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 08/13] dmaengine: at_xdmac: Move the free desc to the tail of the desc list Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-12-13 8:07 ` Vinod Koul
2021-12-13 8:07 ` Vinod Koul
2021-12-13 8:51 ` Tudor.Ambarus [this message]
2021-12-13 8:51 ` Tudor.Ambarus
2021-12-13 8:59 ` Vinod Koul
2021-12-13 8:59 ` Vinod Koul
2021-12-13 9:00 ` Vinod Koul
2021-12-13 9:00 ` Vinod Koul
2021-12-13 9:22 ` Tudor.Ambarus
2021-12-13 9:22 ` Tudor.Ambarus
2021-12-13 9:27 ` Tudor.Ambarus
2021-12-13 9:27 ` Tudor.Ambarus
2021-11-25 9:00 ` [PATCH v2 09/13] dmaengine: at_xdmac: Fix concurrency over xfers_list Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 10/13] dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_advance_work() Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 11/13] dmaengine: at_xdmac: Fix lld view setting Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 12/13] dmaengine: at_xdmac: Fix at_xdmac_lld struct definition Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
2021-11-25 9:00 ` [PATCH v2 13/13] dmaengine: at_xdmac: Fix race over irq_status Tudor Ambarus
2021-11-25 9:00 ` Tudor Ambarus
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