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 Mon, 16 May 2016 19:28:43 +0200 (CEST)
Subject: Re: svn commit: r299933 - in head/sys:
 compat/linuxkpi/common/include/linux sys
To: "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com>
References: <201605160956.u4G9umAT025380@repo.freebsd.org>
 <222500EB-85C1-4FF7-ADB9-0BD71F55D835@gmail.com>
 <308052a8-f574-5725-f6d7-e395956ca78a@selasky.org>
 <4049F31C-6F86-4284-B3A5-8A4640671E43@gmail.com>
Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
From: Hans Petter Selasky <hps@selasky.org>
Message-ID: <d6e1a995-b7dc-1d0c-e923-15bd321e5c3e@selasky.org>
Date: Mon, 16 May 2016 19:32:02 +0200
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On 05/16/16 18:51, Ngie Cooper (yaneurabeya) wrote:
>
>> On May 16, 2016, at 09:47, Hans Petter Selasky <hps@selasky.org> wrote:
>>
>> On 05/16/16 18:31, Ngie Cooper (yaneurabeya) wrote:
>>> Dumb question — couldn’t we run the check without locking Giant, then delete the child, e.g.
>>>
>>> if (bsddev != NULL) {
>>>    mtx_lock(&Giant);
>>>    device_delete_child(device_get_parent(bsddev), bsddev);
>>>    mtx_unlock(&Giant);
>>> }
>>> put_device(dev);
>>
>> I guess so. Does it make a difference for you?
>
> First off, how often does the bsddev == NULL case occur?
>
> If it doesn’t occur often, doing this increases contention on Giant unnecessarily…

In general this piece of code is called very rarely. I'll look into it.

--HPS