From: "Sricharan" <sricharan@codeaurora.org>
To: 'Arnd Bergmann' <arnd@arndb.de>
Cc: devicetree@vger.kernel.org, architt@codeaurora.org,
linux-arm-msm@vger.kernel.org, joro@8bytes.org,
iommu@lists.linux-foundation.org, robdclark@gmail.com,
srinivas.kandagatla@linaro.org,
laurent.pinchart@ideasonboard.com, treding@nvidia.com,
robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org,
stepanm@codeaurora.org
Subject: RE: [PATCH V4 6/7] iommu/msm: Use writel_relaxed and add a barrier
Date: Fri, 20 May 2016 16:48:26 +0530 [thread overview]
Message-ID: <001301d1b289$58e56f70$0ab04e50$@codeaurora.org> (raw)
In-Reply-To:
Hi Arnd,
>>
>>If you need the barrier after the write, it probably was already faulty
>>before, because writel only implies a barrier before the store, not
>>after. Of course all the barriers likely made the whole process so
>>slow that you never hit that race in the end.
>
>ya, it could have worked in this way and i never saw a race issue before this.
>The only reason for changing this was to optimise out the additonal barriers
>that were happening. I do not see any issue now as well, only that the writes would
>be faster.
>
I reposted a patch here [1] with comments, i had to delete the
old accessors though as it became unused now.
http://www.spinics.net/lists/arm-kernel/msg505448.html
Regards,
Sricharan
WARNING: multiple messages have this Message-ID (diff)
From: sricharan@codeaurora.org (Sricharan)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V4 6/7] iommu/msm: Use writel_relaxed and add a barrier
Date: Fri, 20 May 2016 16:48:26 +0530 [thread overview]
Message-ID: <001301d1b289$58e56f70$0ab04e50$@codeaurora.org> (raw)
In-Reply-To: 2638968.1a16UdaY62@wuerfel
Hi Arnd,
>>
>>If you need the barrier after the write, it probably was already faulty
>>before, because writel only implies a barrier before the store, not
>>after. Of course all the barriers likely made the whole process so
>>slow that you never hit that race in the end.
>
>ya, it could have worked in this way and i never saw a race issue before this.
>The only reason for changing this was to optimise out the additonal barriers
>that were happening. I do not see any issue now as well, only that the writes would
>be faster.
>
I reposted a patch here [1] with comments, i had to delete the
old accessors though as it became unused now.
http://www.spinics.net/lists/arm-kernel/msg505448.html
Regards,
Sricharan
next prev parent reply other threads:[~2016-05-20 11:18 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-16 6:48 [PATCH V4 0/7] iommu/msm: Add DT adaptation and generic bindings support Sricharan R
2016-05-16 6:48 ` Sricharan R
2016-05-16 6:48 ` [PATCH V4 1/7] iommu/msm: Add DT adaptation Sricharan R
2016-05-16 6:48 ` Sricharan R
[not found] ` <1463381341-30498-1-git-send-email-sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2016-05-16 6:48 ` [PATCH V4 2/7] documentation: iommu: Add bindings for msm,iommu-v0 ip Sricharan R
2016-05-16 6:48 ` [PATCH V4 2/7] documentation: iommu: Add bindings for msm, iommu-v0 ip Sricharan R
[not found] ` <1463381341-30498-3-git-send-email-sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2016-05-16 16:44 ` [PATCH V4 2/7] documentation: iommu: Add bindings for msm,iommu-v0 ip Rob Herring
2016-05-16 16:44 ` Rob Herring
2016-05-18 12:08 ` Sricharan
2016-05-18 12:08 ` [PATCH V4 2/7] documentation: iommu: Add bindings for msm, iommu-v0 ip Sricharan
2016-05-16 6:48 ` [PATCH V4 3/7] iommu/msm: Move the contents from msm_iommu_dev.c to msm_iommu.c Sricharan R
2016-05-16 6:48 ` Sricharan R
2016-05-16 6:48 ` [PATCH V4 4/7] iommu/msm: Add support for generic master bindings Sricharan R
2016-05-16 6:48 ` Sricharan R
2016-05-16 6:48 ` [PATCH V4 5/7] iommu/msm: use generic ARMV7S short descriptor pagetable ops Sricharan R
2016-05-16 6:48 ` Sricharan R
2016-05-16 6:49 ` [PATCH V4 6/7] iommu/msm: Use writel_relaxed and add a barrier Sricharan R
2016-05-16 6:49 ` Sricharan R
2016-05-17 13:52 ` Arnd Bergmann
2016-05-17 13:52 ` Arnd Bergmann
2016-05-18 12:07 ` Sricharan
2016-05-18 12:07 ` Sricharan
2016-05-18 12:15 ` Arnd Bergmann
2016-05-18 12:15 ` Arnd Bergmann
2016-05-18 12:33 ` Sricharan
2016-05-18 12:33 ` Sricharan
2016-05-20 11:18 ` Sricharan [this message]
2016-05-20 11:18 ` Sricharan
2016-05-16 6:49 ` [PATCH V4 7/7] iommu/msm: Remove driver BROKEN Sricharan R
2016-05-16 6:49 ` Sricharan R
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