freebsd-skq/sys/amd64/include/pcpu_aux.h
Konstantin Belousov 5e921ff49e amd64: move pcb out of kstack to struct thread.
This saves 320 bytes of the precious stack space.

The only negative aspect of the change I can think of is that the
struct thread increased by 320 bytes obviously, and that 320 bytes are
not swapped out anymore. I believe the freed stack space is much more
important than that.  Also, current struct thread size is 1392 bytes
on amd64, so UMA will allocate two thread structures per (4KB) slab,
which leaves a space for pcb without increasing zone memory use.

Reviewed by:	alc, markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D22138
2019-10-25 20:09:42 +00:00

63 lines
2.2 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 The FreeBSD Foundation
*
* This software was developed by Konstantin Belousov <kib@FreeBSD.org>
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE_PCPU_AUX_H_
#define _MACHINE_PCPU_AUX_H_
#ifndef _KERNEL
#error "Not for userspace"
#endif
#ifndef _SYS_PCPU_H_
#error "Do not include machine/pcpu_aux.h directly"
#endif
/* Required for counters(9) to work on x86. */
_Static_assert(sizeof(struct pcpu) == UMA_PCPU_ALLOC_SIZE, "fix pcpu size");
extern struct pcpu *__pcpu;
extern struct pcpu temp_bsp_pcpu;
static __inline __pure2 struct thread *
__curthread(void)
{
struct thread *td;
__asm("movq %%gs:%P1,%0" : "=r" (td) : "n" (offsetof(struct pcpu,
pc_curthread)));
return (td);
}
#define curthread (__curthread())
#define curpcb (&curthread->td_md.md_pcb)
#endif /* _MACHINE_PCPU_AUX_H_ */