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Subject: Re: svn commit: r338829 - head/sys/kern
To: Mateusz Guzik <mjg@FreeBSD.org>, src-committers@freebsd.org,
 svn-src-all@freebsd.org, svn-src-head@freebsd.org
References: <201809201332.w8KDWeX4014010@repo.freebsd.org>
From: Eric van Gyzen <eric@vangyzen.net>
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Date: Thu, 20 Sep 2018 10:13:24 -0500
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On 9/20/18 8:32 AM, Mateusz Guzik wrote:
>    fd: prevent inlining of _fdrop thorough kern_descrip.c
>    
>    fdrop is used in several places in the file and almost never has to call
>    _fdrop. Thus inlining it is a pure waste of space.
>    

> -int
> +int __noinline
>   _fdrop(struct file *fp, struct thread *td)

I wonder if some compilers have an attribute for "cold" versus "hot" 
that would indicate that the function is called seldom versus often.  It 
could influence not only inlining, but also prediction of branches that 
lead to an unconditional call to it.

Eric