From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: John Garry <john.garry@huawei.com>
Cc: jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
linuxarm@huawei.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org, Xiaofei Tan <tanxiaofei@huawei.com>
Subject: Re: [PATCH v2] scsi: hisi_sas: optimise DMA slot memory
Date: Sat, 01 Jul 2017 17:07:22 -0400 [thread overview]
Message-ID: <yq137afx3w5.fsf@oracle.com> (raw)
In-Reply-To: <1498741334-171060-1-git-send-email-john.garry@huawei.com> (John Garry's message of "Thu, 29 Jun 2017 21:02:14 +0800")
John,
> Currently we allocate 3 sets of DMA memories from separate
> pools for each slot. This is inefficient in terms of memory usage
> (buffers are less than 1 page in size, so we lose due to alignment),
> and also time spent in doing 3 allocations + de-allocations per slot,
> instead of 1.
>
> To optimise, combine the 3 DMA buffers into a single buffer from a
> single pool.
Applied to 4.13/scsi-queue. Thank you!
--
Martin K. Petersen Oracle Linux Engineering
WARNING: multiple messages have this Message-ID (diff)
From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: John Garry <john.garry@huawei.com>
Cc: <jejb@linux.vnet.ibm.com>, <martin.petersen@oracle.com>,
<linuxarm@huawei.com>, <linux-scsi@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Xiaofei Tan <tanxiaofei@huawei.com>
Subject: Re: [PATCH v2] scsi: hisi_sas: optimise DMA slot memory
Date: Sat, 01 Jul 2017 17:07:22 -0400 [thread overview]
Message-ID: <yq137afx3w5.fsf@oracle.com> (raw)
In-Reply-To: <1498741334-171060-1-git-send-email-john.garry@huawei.com> (John Garry's message of "Thu, 29 Jun 2017 21:02:14 +0800")
John,
> Currently we allocate 3 sets of DMA memories from separate
> pools for each slot. This is inefficient in terms of memory usage
> (buffers are less than 1 page in size, so we lose due to alignment),
> and also time spent in doing 3 allocations + de-allocations per slot,
> instead of 1.
>
> To optimise, combine the 3 DMA buffers into a single buffer from a
> single pool.
Applied to 4.13/scsi-queue. Thank you!
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2017-07-01 21:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-29 13:02 [PATCH v2] scsi: hisi_sas: optimise DMA slot memory John Garry
2017-06-29 13:02 ` John Garry
2017-07-01 21:07 ` Martin K. Petersen [this message]
2017-07-01 21:07 ` Martin K. Petersen
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