2006-01-16 23:03:38 -07:00
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/*
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* linux/arch/x86_64/ia32/mm/mmap.c
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*
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* flexible mmap layout support
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*
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* Based on the i386 version which was
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*
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* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*
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* Started by Ingo Molnar <mingo@elte.hu>
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*/
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#include <linux/personality.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-20 14:22:52 -07:00
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#include <linux/sched.h>
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2006-01-16 23:03:38 -07:00
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/*
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* Top of mmap area (just below the process stack).
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*
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* Leave an at least ~128 MB hole.
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*/
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#define MIN_GAP (128*1024*1024)
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#define MAX_GAP (TASK_SIZE/6*5)
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static inline unsigned long mmap_base(struct mm_struct *mm)
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{
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unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
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unsigned long random_factor = 0;
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if (current->flags & PF_RANDOMIZE)
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random_factor = get_random_int() % (1024*1024);
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if (gap < MIN_GAP)
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gap = MIN_GAP;
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else if (gap > MAX_GAP)
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gap = MAX_GAP;
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return PAGE_ALIGN(TASK_SIZE - gap - random_factor);
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}
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/*
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* This function, called very early during the creation of a new
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* process VM image, sets up which VM layout function to use:
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*/
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void ia32_pick_mmap_layout(struct mm_struct *mm)
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{
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/*
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* Fall back to the standard layout if the personality
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* bit is set, or if the expected stack growth is unlimited:
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*/
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if (sysctl_legacy_va_layout ||
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(current->personality & ADDR_COMPAT_LAYOUT) ||
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current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY) {
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mm->mmap_base = TASK_UNMAPPED_BASE;
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mm->get_unmapped_area = arch_get_unmapped_area;
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mm->unmap_area = arch_unmap_area;
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} else {
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mm->mmap_base = mmap_base(mm);
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mm->get_unmapped_area = arch_get_unmapped_area_topdown;
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mm->unmap_area = arch_unmap_area_topdown;
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}
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}
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