From: Rob Herring <robh@kernel.org>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Grant Likely <glikely@secretlab.ca>
Subject: Re: [PATCH 0/6] Shrinking DT memory usage
Date: Fri, 6 Oct 2017 17:10:22 -0500 [thread overview]
Message-ID: <CAL_JsqLDhf2tx5PHAnY9X3ju42BayVmJ1KONoKFhhbSaxaKGHQ@mail.gmail.com> (raw)
In-Reply-To: <nycvar.YSQ.7.76.1710061726330.1834@knanqh.ubzr>
On Fri, Oct 6, 2017 at 4:30 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> On Thu, 5 Oct 2017, Rob Herring wrote:
>
>> On kernels with a minimal config and a RAM target in the 100s of KB, DT
>> is quite a hog of runtime memory usage. How much is dependent on how many
>> nodes and properties in the DT which have a corresponding struct device_node
>> and struct property in the kernel. Just skipping disabled nodes saves a
>> lot by not creating the device_nodes in the first place[1], but there's
>> more low hanging fruit by making some of the fields in struct property and
>> struct device_node optional. With the changes here, the memory usage goes
>> from 17KB to under 8KB on QEMU's ARM virt machine which is a relatively
>> small DT.
>
> My test case went from 118072 bytes ddown to 21548 bytes with this
> series.
Did that include the changes for FDT skipping status=disabled and to
stop storing the full path of every node? With those 2 alone you said
it dropped to 25K.
> Tested-by: Nicolas Pitre <nico@linaro.org>
Thanks.
Rob
WARNING: multiple messages have this Message-ID (diff)
From: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Nicolas Pitre <nicolas.pitre-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Frank Rowand
<frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Grant Likely <glikely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Subject: Re: [PATCH 0/6] Shrinking DT memory usage
Date: Fri, 6 Oct 2017 17:10:22 -0500 [thread overview]
Message-ID: <CAL_JsqLDhf2tx5PHAnY9X3ju42BayVmJ1KONoKFhhbSaxaKGHQ@mail.gmail.com> (raw)
In-Reply-To: <nycvar.YSQ.7.76.1710061726330.1834-fMhRO7WWcppj+hNMo8g0rg@public.gmane.org>
On Fri, Oct 6, 2017 at 4:30 PM, Nicolas Pitre <nicolas.pitre-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On Thu, 5 Oct 2017, Rob Herring wrote:
>
>> On kernels with a minimal config and a RAM target in the 100s of KB, DT
>> is quite a hog of runtime memory usage. How much is dependent on how many
>> nodes and properties in the DT which have a corresponding struct device_node
>> and struct property in the kernel. Just skipping disabled nodes saves a
>> lot by not creating the device_nodes in the first place[1], but there's
>> more low hanging fruit by making some of the fields in struct property and
>> struct device_node optional. With the changes here, the memory usage goes
>> from 17KB to under 8KB on QEMU's ARM virt machine which is a relatively
>> small DT.
>
> My test case went from 118072 bytes ddown to 21548 bytes with this
> series.
Did that include the changes for FDT skipping status=disabled and to
stop storing the full path of every node? With those 2 alone you said
it dropped to 25K.
> Tested-by: Nicolas Pitre <nico-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Thanks.
Rob
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next prev parent reply other threads:[~2017-10-06 22:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-05 19:44 [PATCH 0/6] Shrinking DT memory usage Rob Herring
2017-10-05 19:44 ` Rob Herring
2017-10-05 19:44 ` [PATCH 1/6] of: fix missing kobject init for !SYSFS && OF_DYNAMIC config Rob Herring
2017-10-05 19:44 ` Rob Herring
2017-10-05 19:44 ` [PATCH 2/6] of: remove struct property.unique_id for FDT Rob Herring
2017-10-06 13:30 ` Grant Likely
2017-10-05 19:44 ` [PATCH 3/6] of: make struct property _flags field configurable Rob Herring
2017-10-05 19:44 ` [PATCH 4/6] of: move kobj_to_device_node() into dynamic.c Rob Herring
2017-10-05 19:44 ` [PATCH 5/6] of: wrap accesses to device_node kobject Rob Herring
2017-10-06 10:09 ` Greg Kroah-Hartman
2017-10-06 10:09 ` Greg Kroah-Hartman
2017-10-05 19:44 ` [PATCH 6/6] of: make kobject and bin_attribute support configurable Rob Herring
2017-10-06 13:55 ` [PATCH 0/6] Shrinking DT memory usage Grant Likely
2017-10-06 21:30 ` Nicolas Pitre
2017-10-06 22:10 ` Rob Herring [this message]
2017-10-06 22:10 ` Rob Herring
2017-10-06 23:24 ` Nicolas Pitre
2017-10-06 23:24 ` Nicolas Pitre
2017-10-07 2:11 ` Frank Rowand
2017-10-07 2:11 ` Frank Rowand
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