svn commit: r324609 - head/sys/sys
Svatopluk Kraus
skra at freebsd.org
Fri Oct 13 23:23:16 UTC 2017
MTX_UNOWNED is a flag. You did not change its value from 4 to 0, you
removed it actually. I have very bad feeling about it. But maybe, it's
really possible and in that case, a very good explanation should be
provided.
Svata
On Fri, Oct 13, 2017 at 10:31 PM, Mateusz Guzik <mjg at freebsd.org> wrote:
> Author: mjg
> Date: Fri Oct 13 20:31:56 2017
> New Revision: 324609
> URL: https://svnweb.freebsd.org/changeset/base/324609
>
> Log:
> mtx: change MTX_UNOWNED from 4 to 0
>
> The value is spread all over the kernel and zeroing a register is
> cheaper/shorter than setting it up to an arbitrary value.
>
> Reduces amd64 GENERIC-NODEBUG .text size by 0.4%.
>
> MFC after: 1 week
>
> Modified:
> head/sys/sys/mutex.h
>
> Modified: head/sys/sys/mutex.h
> ==============================================================================
> --- head/sys/sys/mutex.h Fri Oct 13 20:29:35 2017 (r324608)
> +++ head/sys/sys/mutex.h Fri Oct 13 20:31:56 2017 (r324609)
> @@ -65,15 +65,11 @@
> * State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
> * with the exception of MTX_UNOWNED, applies to spin locks.
> */
> +#define MTX_UNOWNED 0x00000000 /* Cookie for free mutex */
> #define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
> #define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
> -#define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
> -#define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_UNOWNED)
> -
> -/*
> - * Value stored in mutex->mtx_lock to denote a destroyed mutex.
> - */
> -#define MTX_DESTROYED (MTX_CONTESTED | MTX_UNOWNED)
> +#define MTX_DESTROYED 0x00000004 /* lock destroyed */
> +#define MTX_FLAGMASK (MTX_RECURSED | MTX_CONTESTED | MTX_DESTROYED)
>
> /*
> * Prototypes
>
More information about the svn-src-all
mailing list