From: Frank Rowand <frowand.list@gmail.com>
To: Chintan Pandya <cpandya@codeaurora.org>,
robh+dt@kernel.org, devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH] of: use hash based search in of_find_node_by_phandle
Date: Fri, 26 Jan 2018 13:29:59 -0800 [thread overview]
Message-ID: <c1c21be3-c279-653c-2529-a9cc325865cc@gmail.com> (raw)
In-Reply-To: <2ac0d70d-074d-5eff-77e9-29d1a246a3ef@gmail.com>
On 01/26/18 13:27, Frank Rowand wrote:
> On 01/26/18 00:22, Chintan Pandya wrote:
>>
>>
>> On 1/26/2018 1:24 AM, Frank Rowand wrote:
>>> On 01/25/18 02:14, Chintan Pandya wrote:
>>>> of_find_node_by_phandle() takes a lot of time finding
>>>> right node when your intended device is too right-side
>>>> in the fdt. Reason is, we search each device serially
>>>> from the fdt, starting from left-most to right-most.
>>> Please give me a pointer to the code that is doing
>>> this search.
>>>
>>> -Frank
>> You can refer include/linux/of.h
>>
>> #define for_each_of_allnodes_from(from, dn) \
>> for (dn = __of_find_all_nodes(from); dn; dn = __of_find_all_nodes(dn))
>> #define for_each_of_allnodes(dn) for_each_of_allnodes_from(NULL, dn)
>>
>> where __of_find_all_nodes() does
>>
>> struct device_node *__of_find_all_nodes(struct device_node *prev)
>> {
>> struct device_node *np;
>> if (!prev) {
>> np = of_root;
>> } else if (prev->child) {
>> np = prev->child;
>> } else {
>> /* Walk back up looking for a sibling, or the end of the structure */
>> np = prev;
>> while (np->parent && !np->sibling)
>> np = np->parent;
>> np = np->sibling; /* Might be null at the end of the tree */
>> }
>> return np;
>> }
>>
>
> Let me restate my question.
>
> Can you point me to the driver code that is invoking
> the search?
>
> -Frank
>
And also the .dts devicetree source file that you are seeing
large overhead with.
next prev parent reply other threads:[~2018-01-26 21:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 10:14 [PATCH] of: use hash based search in of_find_node_by_phandle Chintan Pandya
[not found] ` <1516875247-19599-1-git-send-email-cpandya-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2018-01-25 14:50 ` Rob Herring
2018-01-26 7:22 ` Chintan Pandya
2018-01-26 15:21 ` Rob Herring
2018-01-25 19:54 ` Frank Rowand
[not found] ` <5a7793df-725e-608d-778b-cb81fde0cc64-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-01-26 8:22 ` Chintan Pandya
2018-01-26 21:27 ` Frank Rowand
2018-01-26 21:29 ` Frank Rowand [this message]
[not found] ` <c1c21be3-c279-653c-2529-a9cc325865cc-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-01-26 21:34 ` Frank Rowand
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