freebsd-dev/sys/vm/vm_init.c
Alan Cox 9e4e511499 Change the order in which the file name, arguments, environment, and
shell command are stored in exec*()'s demand-paged string buffer.  For
a "buildworld" on an 8GB amd64 multiprocessor, the new order reduces
the number of global TLB shootdowns by 31%.  It also eliminates about
330k page faults on the kernel address space.

Change exec_shell_imgact() to use "args->begin_argv" consistently as
the start of the argument and environment strings.  Previously, it
would sometimes use "args->buf", which is the start of the overall
buffer, but no longer the start of the argument and environment
strings.  While I'm here, eliminate unnecessary passing of "&length"
to copystr(), where we don't actually care about the length of the
copied string.

Clean up the initialization of the exec map.  In particular, use the
correct size for an entry, and express that size in the same way that
is used when an entry is allocated.  The old size was one page too
large.  (This discrepancy originated in 2004 when I rewrote
exec_map_first_page() to use sf_buf_alloc() instead of the exec map
for mapping the first page of the executable.)

Reviewed by:	kib
2010-07-25 17:43:38 +00:00

214 lines
6.6 KiB
C

/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* from: @(#)vm_init.c 8.1 (Berkeley) 6/11/93
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* Initialize the Virtual Memory subsystem.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/selinfo.h>
#include <sys/imgact.h>
#include <sys/pipe.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>
long physmem;
static int exec_map_entries = 16;
TUNABLE_INT("vm.exec_map_entries", &exec_map_entries);
SYSCTL_INT(_vm, OID_AUTO, exec_map_entries, CTLFLAG_RD, &exec_map_entries, 0,
"Maximum number of simultaneous execs");
/*
* System initialization
*/
static void vm_mem_init(void *);
SYSINIT(vm_mem, SI_SUB_VM, SI_ORDER_FIRST, vm_mem_init, NULL);
/*
* vm_init initializes the virtual memory system.
* This is done only by the first cpu up.
*
* The start and end address of physical memory is passed in.
*/
/* ARGSUSED*/
static void
vm_mem_init(dummy)
void *dummy;
{
/*
* Initializes resident memory structures. From here on, all physical
* memory is accounted for, and we use only virtual addresses.
*/
vm_set_page_size();
virtual_avail = vm_page_startup(virtual_avail);
/*
* Initialize other VM packages
*/
vm_object_init();
vm_map_startup();
kmem_init(virtual_avail, virtual_end);
pmap_init();
vm_pager_init();
}
void
vm_ksubmap_init(struct kva_md_info *kmi)
{
vm_offset_t firstaddr;
caddr_t v;
vm_size_t size = 0;
long physmem_est;
vm_offset_t minaddr;
vm_offset_t maxaddr;
vm_map_t clean_map;
/*
* Allocate space for system data structures.
* The first available kernel virtual address is in "v".
* As pages of kernel virtual memory are allocated, "v" is incremented.
* As pages of memory are allocated and cleared,
* "firstaddr" is incremented.
* An index into the kernel page table corresponding to the
* virtual memory address maintained in "v" is kept in "mapaddr".
*/
/*
* Make two passes. The first pass calculates how much memory is
* needed and allocates it. The second pass assigns virtual
* addresses to the various data structures.
*/
firstaddr = 0;
again:
v = (caddr_t)firstaddr;
v = kern_timeout_callwheel_alloc(v);
/*
* Discount the physical memory larger than the size of kernel_map
* to avoid eating up all of KVA space.
*/
physmem_est = lmin(physmem, btoc(kernel_map->max_offset -
kernel_map->min_offset));
v = kern_vfs_bio_buffer_alloc(v, physmem_est);
/*
* End of first pass, size has been calculated so allocate memory
*/
if (firstaddr == 0) {
size = (vm_size_t)v;
firstaddr = kmem_alloc(kernel_map, round_page(size));
if (firstaddr == 0)
panic("startup: no room for tables");
goto again;
}
/*
* End of second pass, addresses have been assigned
*/
if ((vm_size_t)((char *)v - firstaddr) != size)
panic("startup: table size inconsistency");
clean_map = kmem_suballoc(kernel_map, &kmi->clean_sva, &kmi->clean_eva,
(long)nbuf * BKVASIZE + (long)nswbuf * MAXPHYS, TRUE);
buffer_map = kmem_suballoc(clean_map, &kmi->buffer_sva,
&kmi->buffer_eva, (long)nbuf * BKVASIZE, FALSE);
buffer_map->system_map = 1;
pager_map = kmem_suballoc(clean_map, &kmi->pager_sva, &kmi->pager_eva,
(long)nswbuf * MAXPHYS, FALSE);
pager_map->system_map = 1;
exec_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr,
exec_map_entries * round_page(PATH_MAX + ARG_MAX + MAXSHELLCMDLEN),
FALSE);
pipe_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr, maxpipekva,
FALSE);
/*
* XXX: Mbuf system machine-specific initializations should
* go here, if anywhere.
*/
/*
* Initialize the callouts we just allocated.
*/
kern_timeout_callwheel_init();
}